Why is my car over heating?

Over Heating CarRecently on a trip to mountains to go hiking, I was traveling with a few friends in a caravan of three vehicles.  About 10 minutes before the trail head, I looked in my rear view mirror and noticed there was now only 1 car behind me instead of two.  We made it to the trail head, and waited assuming our friends had stopped for a quick photo shoot, or maybe a bathroom break.  In the pass we’d stopped in to hike, no one had any cell phone service so we had trouble reaching our friends after it had been a surprisingly long time without their arrival.  We decided to send out a search car and when they didn’t return either, our last car headed back as well.  We found the rest of our group parked on the side of the road with the hood open looking very frustrated and cold.  Their car had over heated due to cooling system problems that left them stuck with a bill for a 100 mile tow truck ride.  The worst part about the breakdown was it was entirely preventable if the owner of the vehicle had taken action a little sooner.

If your car is overheating on a regular basis it’s very important for you to get the problem fixed right away so you don’t get stranded miles from home and stuck with an expensive tow bill.  The engine in your vehicle is also designed to operate under a very specific set of parameters.  One of the parameters is the operating temperature.  Even if the temperature gauge doesn’t reach the top, you can still be doing permanent damage to your engine costing you more money in repairs and possibly damaging your engine past the ability to repair.  In order to diagnose your overheating problems, lets look at all the possible reasons a car might over heat:

Possible causes of overheating:

  • Clogged radiator (internally or externally)
  • Broken thermostat
  • Clogged or fowled coolant passages
  • Improper air/fuel mixture or ignition timing
  • Low coolant

If your vehicle has an externally clogged radiator, you can usually see it from the front of your vehicle.  Look behind the grill or bumper for the fins of the radiator.  If there are leaves, dirt or debris blocking air from flowing over the fins of your radiator it can cause your car to overheat.  Removing the blockage either by washing or brushing away the debris can solve your over heating problem.  You have to be extremely careful while removing external blockage from the radiator to avoid both damaging the delicate radiator fins and from injuring your hands on the sharp edges.  You can check for internal radiator clogs by opening the radiator cap when the car is cool.  Check the fluid and the radiator for a brown color, or suspended contaminates in the coolant.  If you have an infrared thermometer, you can also check the temperatures at different points in the radiator while the car is running and warm.  They should drop uniformly as coolant travels from the top hose of the radiator diagonally to the bottom hose.  If there are places where the temperature is the same, or drops significantly, you probably have an internal clog.  The best thing to do in this case is a full cooling system flush using BlueDevil Radiator Flush to clean out the clog and add fresh coolant to your clean system.  You can purchase BlueDevil Radiator Flush here.

Overheating ProblemsA broken thermostat can also cause your car to overheat.  The thermostat in your engine controls the flow of coolant.  When the engine is cold, the coolant is allowed to circulate through the engine block and the heater core in your car, but not the radiator.  As the coolant reaches operating temperature, the thermostat opens to allow some of the coolant to flow through the radiator and be cooled.  This keeps the coolant in your engine at a specific temperature designed for best operation.  If the thermostat breaks, it can stick shut.  This will keep the coolant from ever entering the radiator and your engine to overheat.  You can check this by checking the temperature of the upper radiator hose.  If it is hot near the radiator after you have driven your car then coolant is flowing through it.  If it is still cold you may have a broken thermostat and should remove the thermostat and test it.  Be careful when checking the upper radiator hose temperature as it could be hot enough to burn.  A thermometer is best for this check.

Why is my car overheatingYou can check for clogged or fowled coolant passages in the same way you would check for an internal radiator clog and also solve that problem by using BlueDevil Radiator Flush.

An improper air fuel mixture can also cause on overheating condition.  A lean condition during combustion will cause a hotter than usual combustion process producing excess heat and possible overheating.  Similarly, late ignition timing can cause excess heat in the combustion process.  If your car is carbureted try adjusting the carburetor to run another step or two rich.  Fuel injected cars rarely run lean, but you may consider checking your fuel system components like the filter, injectors and O2 sensor.  If your car is old enough to have a distributor you can check and adjust your ignition timing to factory specifications, but even on older cars this problem rarely exists.

The most likely cause of an engine overheating is a low coolant level.  Your cooling system has many connections and components that are susceptible to failure even under normal conditions.  There are multiple gaskets, hoses and seals that may fail in the cooling system causing a leak.  If you notice puddles of coolant on the ground, you most likely have an external coolant leak from a hose or the radiator.  If you notice coolant inside your car, you likely have a broken heater core.  If you notice white smoke coming from your exhaust, or bubbles in your coolant overflow tank, it is possible that you have a leaking head gasket.  For any of these leaks you can use BlueDevil Pour-N-Go or BlueDevil Head Gasket Sealer to seal the leak.  BlueDevil products are guaranteed to seal your leak permanently and have no particulate matter to clog or fowl any components in your cooling system. 

BlueDevil Pour-N-Go Head Gasket Sealer

You can purchase BlueDevil Pour-N-Go here and BlueDevil Head Gasket Sealer here.

You can also purchase all of the guaranteed BlueDevil products at your local auto parts stores:

  • O’Reilly Auto Parts
  • Autozone
  • Pep Boy’s
  • CarQuest Auto Parts
  • Advance Auto Parts
  • Bennett Auto Supply
  • Prime Automotive
  • NAPA

70 responses to “Why is my car over heating?

  1. My 2000 Cadillac Deville overheated before the 50 minute Bluedevil process time, so is there anything that can be done now? The longest It’d run before overheating was 39 min. Any suggestions besides to save the car would be greatly appreciated!

    1. It sounds like your leak may be a little larger than what BlueDevil is intended to repair. Please contact our claims department 888.863.0426 (option 1) so that we may assist you in getting a refund.

        1. Gel-

          The BlueDevil Head Gasket Sealer does not contain any solid or particulate matter in the product, so it is non-clogging. As long as you are using it as intended, you wouldn’t have any issues.

          Thank you!

          -BDP

  2. My engine is a QD32 and it has been giving warning of high temperature and we have replaced the cylinder head gasket and cleaned the radiator including replacing the radiator cap but it still has that problem, Kindly advise.

    1. Moffat-

      There are a number of reasons your vehicle could be overheating. It could be a defective fan switch, fan clutch, clogged or restricted cores, or heavy scale and sediment deposits within your cooling system.

      At this point we recommend having your vehicle looked at by a Nissan specialist so that you can have a better idea on what exactly you are dealing with. Once you are able to pinpoint the cause of the overheating you will have a much better idea on how to solve the problem.

      -BDP

  3. my 1990 Pontiac grand prix is constantly overheating after short, brief drives. I just bought it from someone who has it in a garage for 2 years. but it was in fairly good condition. Could it be overheating just because it hasn’t been driven in awhile, or what i really think it is the thermostat could be broken. But the gauge inside of the car is still telling me that it is getting hot. If it is that, where would that be located and how would i replace it? could i just take it to autozone and ask them to help me with it? Looking for a quick cheep fix, because this is my first car. I have someone who will help me install it, all i need to know is what could be wrong with it

    1. Rain-

      There are a multitude of possible reasons the vehicle may be overheating. Because the car has been sitting for awhile you may want to take it in to a certified mechanic to truly diagnose the current problem or problems at hand.

      Thank You!

      -BDP

  4. I replaced the water pump and thermostat in my 96 grand prix still runs hot,my top hose be hot and the bottom hose cool. But my Radiator Be real hot?

    1. Joe-

      It sounds like you may be having a restriction of flow. We recommend first checking that the thermostat is functioning properly; if not, you should replace it.

      If you are still having these issues after the thermostat has been replaced then we recommend running a bottle of the BlueDevil Radiator Flush through your system to remove any antifreeze build up or other restrictions from your cooling system.

      Thank You!

      -BDP

  5. I have a 1999 z28 camero with v8 engine. My low coolant light comes on but the radiator and the coolant tank are both full. The car runs at a constant 210 degrees. It takes about 8-10 minutes for the light to go on but then it stays on.

    1. Terri,

      Thanks for your question about your 99 Camaro. It sounds like you have a bad coolant level sensor. Your radiator should have a sensor just below the radiator cap on the back of your radiator that measures the coolant level there. These sensors are known for going bad, and usually act like you are describing and come on after a few minutes of driving. Try replacing the sensor and seeing if your low coolant light stays off.

        1. Alejandro-

          Thank you for asking about your Chevy Impala. Based on your description, it is tough to say exactly why your vehicle is overheating. If you are hearing the fans come on, you may have a restriction in the cooling system or there may be a build up of pressure in the system. We recommend taking the vehicle to a certified ASE mechanic and having it properly diagnosed.

          Thank you!

          -BDP

  6. 02 Subaru after a complete head gasket job it overheated often. The Mech did bad job. Oil spiting out or radiator. A new Mech used Blue devil sealer has fixed all that.
    Now on long drives hot days it over heats again. How can we flush the radiator ?

  7. My 2005 gmc envoy xl has a problem:temp guage got over 200+ degrees, over 3/4 till hot area, pulled to a stop, let engine cool down, opened radiator cap, coolent full to top, very green, ran it for 5 minutes, guage went to halfway/ normal, but didn’t drive it, what could be the problem??

    1. Hume-

      Thanks for your question about your 2005 Envoy. Great job pulling over and stopping when the temperature gauge got too high! If your coolant is full the problem most likely stemmed from your thermostat or your cooling fans. Try letting your car idle up to temperature and seeing if the fans kick on before the temperature gauges goes up. If the fans are working properly then you most likely just need a new thermostat to help keep things cool.

      -BDP

  8. I have a 2001 Pt Cruiser and it runs hot but if I turn on the heater it cools down but now even that isnt doing anything. I changed the thermostat and that helped for a bit but it is doing that again. I have coolant in the car and everything and it is also in the overflow tank. How do I tell if my cores in my radiator are clogged or if my water pump is still working properly???

    1. Kelli-

      If you were getting heat in your Pt Cruiser, then your water pump is most likely working properly and the heater core is not clogged. You may have some other restriction in your cooling system causing the vehicle to overheat. We recommend having your cooling system flushed and see if that solves the issue. If not, you may want to have the vehicle looked at by an ASE certified mechanic.

      Thank you!

      -BDP

  9. My car was leaking so I had the water pump replaced. But now my car is still over heating and it’s now leaking from the top of my coolant tank. Do you think it may be clogged?

    1. Gabrielle-

      It is possible that there is an air bubble stuck in the system. You may refer to your owners manual on how to bleed the cooling system so that you may burp the system.

      The other possibility would be that you are getting combustion/exhaust gases in the cooling system due to a leak. This can be tested in using a Block-Dye Tester.

      Thank You!

      -BDP

  10. 3 month’s ago i blew my head gaskets, radiator and fuel injections were fixed. Cost me 2,000 🙁 but I’ve had it for a month now, i notice something was squeaking couldn’t tell where it was coming from, figured maybe my brakes where going out. The nexti went to work came home then 2 hours later, I went to gas station which is right around the corner from my house. As i was pulling in I seen how my temperature gauge was in the middle and went quickly to hot so i went ahead and parked my truck. It was really steamy popped hood and notice steam was really coming from around fan belt area…..So my thoughts are maybe that squeaking sound was from my belt???? Im not sure any opinions on why my truck started overheating once again, when i thought it was done taken cared of????

    1. Brenda,

      Thanks for your question about your truck. It sounds like you simply had a water pump go bad. If your water pumped started to go bad it could have started leaking around the pump shaft seal. If that was the case it would have gotten your belts wet which would have caused them to squeak like you described. Try removing the fan belts and seeing if your water pump pulley is loose and you can move it at all. If you can, replacing your water pump should get you back on the road!

      Thanks again!
      -BD Auto Pro

  11. my car overheated today. I immediately turn the heat on and the temp went straight to normal. What could this be? I just got a brand new radiator 2 months ago.

    1. Jessica-

      Your vehicle can overheat for a number of different reasons. Based on your description, it is hard to pinpoint what the reason is but, you could have a defective fan switch or a defective fan clutch. We recommend bringing your vehicle to a certified ASE mechanic and getting a proper diagnosis.

      Thank you!

      -BDP

  12. i have an 03 cadillac cts overheating issues i found that i had oil in the water so i flushed the radiator & cleaned the hoses put in a radiator cleaning liquid & then flushed it again & added blue devil & it still over smokes overheats & turns off

    1. Ira-

      The BlueDevil Head Gasket Sealer is intended for coolant/water leaks only. Unfortunately, we do not manufacture a product for when oil is getting into the radiator. Feel free to contact our technical support line at 888-863-0426 with any other questions.

      Thank you!

      -BDP

  13. When i firsr start driving my 1998 Lincoln Town Car the heat guage goes to the line before the H then the car idle and the temp guage goes back to normal and stay there.but i notice water on the passenger side floor. What could the problems be

    1. Corey,

      Thanks for your question about your Lincoln Town Car. It sounds like your thermostat is sticking shut first thing in the morning causing your car to overheat before the thermostat opens and allows coolant flow to your radiator. This overheating is also causing an excessively high pressure in your cooling system which would cause your heater core to leak which is why you get coolant on the passenger floor.

      Our recommendation would be to change your thermostat first and see if that stops your overheating and your leak. If the leak continues you may need to replace your heater core as well.

      Thanks again for your question!
      -BD Auto Pro

  14. Range Rover owner here. I recently purchased BlueDevil PourNGo. After doing so I realized my radiator was clogged externally with dirt and grime. After cleaning with a soap sprayer and water, inside and out. I reattached the rad. Truck ran well. One day later, bubbles from the overflow tank and overheating as well as white smoke from tailpipe and left side exhaust manifold…?????? Anything I can do before I go buying a new engine. I.E. gasket was previously changed along with water pump and thermostat.

    1. JustRain-

      We would recommend using the BlueDevil Head Gasket Sealer for your Range Rover. Based on your description, it sounds like your vehicle may be getting combustion/exhaust gases blowing into the cooling system and creating pressure. To give yourself the best overall chance of BlueDevil working successfully, in addition to the directions, you should remove the spark plug from the cylinder with the leak; this will be the spark plug from the cylinder with a low compression reading. If you are not sure which one that is, you may pull all of the spark plugs and will sometimes notice one will have a white-crystal-like substance on it and/or may look dirty; this is the plug you should pull. Leave that plug out for the 50 minute idle in order to relieve the pressure from building up and thus allowing the product to seal properly.

      Thank you!

      -BDP

  15. I have a 2003 Kia Sorento my car started overheating i had a mechanic look at my car and he told me it was my water pump so i had the water pump replaced along with the timing belt on my car this happened back in February 2014 and everything was fine. Well my car started overheating again on September 24, 2015 hadn’t had any problems with overheating since i had my water pump replaced in 2014 it just out of the blue started overheating again i don’t recall hearing the fan come on but my kids and i had to pull over and wait for the car to cool down then i had a family member come & help us since we were only 5min. from home they checked the overflow to see if there was any water/coolant in the tank and once it cooled down i drove on home and it started to overheat as we pulled in the driveway can you please give me any idea about what may have caused my car to overheat again.

    1. Crystal-

      There are a number of different reasons as to why your vehicle would overheat. Based on your description, it could be that you have a defective fan switch or a defective fan clutch. We recommend having the vehicle looked at by an ASE certified mechanic for a proper diagnosis.

      Thank you!

      -BDP

  16. I have a 2002 Chevy Chevrolet she has been overheating while i drive for a shorty distance( 3 or 4 miles) I’m good with antifreeze no visible leaks but the coolant light blinks on & off but like i said i have full tank of antifreeze, what can be causing her to overheat?

    1. Sara-

      Your Chevy could be overheating for a few different reasons. If you are not noticing a loss of coolant and your fans are coming on and working properly, it’s possible you have clog or a restriction in the cooling system. We recommend having the cooling system flushed and hopefully that alleviates the overheating. If not, you may want to bring the vehicle to a certified ASE mechanic for a further diagnosis.

      Thank you!

      -BDP

  17. 2005 Ford freestyle temp gauge shows hot after driving for a short distance then goes back to normal and then no other problems. Changed the water pump last year thermostat and radiator last week and same problem but if I let the car warm up that doesn’t happen

    1. G,

      Thanks for your question about your Ford Freestyle. It sounds like your thermostat is slow to open for some reason. You could try performing a coolant flush to make sure there are not clogs or blockages in your system. Use BlueDevil Radiator Flush (available here: http://store.gobdp.com/radiator-flush-00204/) to clean out your cooling system. Also, make sure your coolant is topped off and all the bubbles are removed from your system. If there is an air bubble trapped at your thermostat it could be causing the slow opening.

      Thanks again for your question!
      -BD Auto Pro

  18. My girl was driving the car this morning and my car is a 2001 grand am and she noticed a little of light smoke coming from under the hood so she looked at heat stick and she said it was going past normal alittle bit and then she said when she drive it would go back to normal. Plz help me on this so i can fix this before it gets to be somthing bigger.

    1. Bryan,

      Thanks for your question about your Grand Am. It sounds like you’ve got a coolant leak causing the smoke and a low coolant level which is causing some overheating. When your car is cold, check around the engine to see if you can figure out where the leak is so you can decide how to fix it. If a hose is cracked or leaking, simply replace that hose. Otherwise, you can use BlueDevil Radiator and Block Sealer or Head Gasket Sealer to seal the leak depending where it is coming from.

      Thanks again for your question!
      -BD Auto Pro

  19. I have a 2003 jeep grand Cherokee that overheats pretty much as soon as I start the car but there is plenty of coolant in the reservoir. The engine also sounds like it’s jumping around… I’m stumped and need suggestions

    1. Anthony,

      Thanks for your question about your Jeep. If you’re also losing coolant, that could be a good indication that you’ve got a blown head gasket. That would cause the overheating and cause whatever cylinder is leaking to misfire causing the jumping. Try checking for other symptoms of a blown head gasket like white smoke from the exhaust, milky oil or bubbles in your radiator.

      If you don’t’ have a blown head gasket it could also be that your timing is way off, in this case, it would be extremely retarded probably, or if our thermostat is stuck shut.

      Thanks again for your question!
      BD Auto Pro

  20. My van is over heating. I replaced the thermo and sensor still over heating. Fans kick on I have heat then lose it all. No leaks other then violent purging from resovuor. Radiator is full. No smoke out of exhaust. What else would stop circulation to engine?

    1. Simon-

      Based on your description, it sounds like your vehicle may be getting combustion/exhaust gases blowing into the cooling system and creating pressure. We would recommend using BlueDevil Head Gasket Sealer to help remedy the problem. To give yourself the best overall chance of BlueDevil working successfully, in addition to the directions, you should remove the spark plug from the cylinder with the leak; this will be the spark plug from the cylinder with a low compression reading. If you are not sure which one that is, you may pull all of the spark plugs and will sometimes notice one will have a white-crystal-like substance on it and/or may look dirty; this is the plug you should pull. Leave that plug out for the 50 minute idle in order to relieve the pressure from building up and thus allowing the product to seal properly.

      Feel free to contact us at 888-863-0426 with any questions.

      Thanks!

      -BDP

  21. I have a 2000 saturn. It does fine while om driving but if I sit still for to long at a red light or leave my car cranked at home running to long, it gets to ablut the halfway point and starts to smoke around where you put the coolant. It did this for the first time about a week ago and leaked all the coolant out. So I bought and changed the thermostat and refilled it. Bought a new motor for my fan, my fan still isnt turning i dont think and its still running hot when I sit to long. Please help me!!

    1. Sahra,

      It does sound like a problem with your cooling fans. If they aren’t coming on after a minute or 2 of idling then that would cause your car to overheat. Since you’ve already replaced the fan motor you can try checking the fan relay as well as your the temperature sensor that turns your fan on. If the relay and sensor are in good conditioning then you may have a wiring problem somewhere in between. For a quick read on tracking down electrical problems, check out our article about that here. https://www.gobdp.com/blog/diagnosing-electrical-problems/.

      Thanks for your question!
      -BD Auto Pro

    1. Charles-

      Please contact our tech support team at 888-863-0426 so that we can get a little more detail into the situation and hopefully be able to help you get the problem remedied.

      Thank you!

      -BDP

  22. I have a 90 Subaru, mildly blown head gasket, with the thermostat housing in the lower radiator hose. As such, I’m not seeing how this product (white label) is going to circulate when added to a cold engine, even when poured slowly. I’m perfectly willing to remove remove my thermostat prior to adding this product–Should I? I’ve seen a number of posts elsewhere claiming the their thermostat became clogged and I’d like to have the maximum possible chance of success. (I did not get the yellow label version as I’m in Alaska in sub-zero temps and running pure water would be an expensive disaster.)

    1. Tom-

      Yes, based on the cooling system setup we do recommend removing the thermostat prior to adding BlueDevil; this will help ensure the system is free flowing.

      Feel free to contact us at 888-863-0426 with any further questions.

      Thank you!

      -BDP

  23. I have a Lexus GS300 and the resolver bubbles over I replaced the radiator thermostat and a they told me it was the head gaskets and I was wondering if blue devil would help this problem

    1. Joseph-

      Based on your description, we would recommend using the BlueDevil Head Gasket Sealer. It sounds like the vehicle may be getting combustion/exhaust gases blowing into the cooling system and creating pressure. To give yourself the best overall chance of BlueDevil working successfully, in addition to the directions, you should remove the spark plug from the cylinder with the leak; this will be the spark plug from the cylinder with the low compression reading. If you are not sure which one that is, you may pull all of the spark plugs and will notice one will have a white-crystal-like substance on it and/or may look dirty; this is the plug you should pull. Leave that plug out for the 50 minute idle in order to relieve the pressure from building up and thus allowing the product to seal properly.

      Thank you!

      -BDP

  24. I have a 2005 Cadillac CTS that I was driving and it overheated today. I let it cool down and when I put water in it there is water leaking from under the car. What could it be? ?

    1. Jennifer-

      It is possible that you have a blown head gasket or some other part of your cooling system is leaking. Please contact our tech support team at 888-863-0426 so that we may get a better understanding as to what is possibly going on with your Cadillac. This will allow us to recommend the appropriate product for getting the vehicle fixed.

      Our regular office hours are Monday – Friday, 8:00 AM – 5:00 PM Eastern Standard Time.

      Thank you!

      -BDP

  25. I have a 2001 Dodge Caravan. The radiator and thermostat were replaced 6 months ago. Just last week the coil was replaced. The same day I got the van back from having the coil replaced it started overheating. I drove it all day with no issues but in the evening after being on the highway for about 20 minutes it was overheating (redlining). I quickly pulled over turned the heat on full blast and waited for it to cool down before turning around and heading home. The next day I drove 4 hours with no issues at all.. 2 days later overheating again.. The day after that no problems. Top rad hose was warm, but not hot to the touch, coolant was full, and fans are running. Any thoughts on what might be causing it to overheat so randomly?

    1. Brenda,

      Thanks for your question about your Dodge Caravan. Based on how intermitent your overheating problem is it sounds more like your thermostat is causing the problem. Even though you just ad it replaced 6 months ago, sometimes even a slight overheating can damage a thermostat so that could be why the problem is continuing. You may also take your Caravan back to the place that replaced the coil and see if they can think of anything they might have changed or damaged that would cause the over heating.

      Thanks again for your question!
      -BD Auto Pro

  26. Yes I have a 2006 Ford Mustang.. I just got a new water pump but I see water leaking around the thermostat and it’s running hot.. Do I need a new thermostat? When I accelerate on the gas I have it all the way to the floor and and won’t go but 40 mph what’s the problem?

    1. Shamdria,

      Thanks for your question about your Mustang. Often times it is smart to replace your thermostat when you replace your water pump simply so you don’t have to drain your coolant twice and because the thermostat is an inexpensive item to replace but can really help keep your car safe. The fact that your car won’t go above 40 MPH no matter how hard you push the gas sounds like an indication of further problems. This could indicate your car is still in limp mode from the last problem you had, could indicate that a sensor was left unplugged during the water pump replacement or could indicate you have bigger problems like a blown head gasket.

      We would recommend taking your car back to the mechanic who replaced the water pump and see if any of the problems you’re having could be due to the water pump replacement and to help you know if you need a new thermostat as well, or if you have bigger problems lurking.

      Thanks again for you question!
      -BD Auto Pro

  27. Hello I have a 2006 Chevrolet trailblazer 5.3 engine. My truck overheats the upper radiator hose gets hot but I can open the radiator cap while it’s hot which is very strange because I know it’s supposed to be pressurized when over heated. It will overheat to about two hundred twenty then back to two hundred ten n keep cylinder back n forth like that while I have the ac on.what do you think it is that is causing it to over heat? Also the hot coolant light does come on along with the check engine light…

    1. Llyod,

      Thanks for your question about your Trailblazer. If you can open the radiator cap while your car is hot without getting coolant shooting then your coolant level must be very low. If your cooling system was full of hot pressurized coolant it would shoot out when you opened the radiator cap. That would also cause the overheating and your temperature gauge to fluctuate as your described. Our recommendation would be to fill your radiator and burp your system to remove the air, then fill your coolant overflow tank as well. If you’ve driven while your temperature gauge is high you may also consider changing your thermostat as it may be damaged.

      Thanks again for your question!
      -BD Auto Pro

  28. I have an 2006 Chrysler 300c with the HDMI engine. Last week it started over heating. I added 50/50 coolant. I can’t get to the radiator cap so I filled the over flow tank to the full mark. Seamed to help till yesterday. It over heated again this time almost to the red zone. I parked the car noticed a drip and a hissing noise from the passenger side between the front of the car and the tire. Could this be a hose issue.

    1. Deborah-

      Thank you for asking about your Chrysler 300C. It is very possible that the vehicle is starting to overheat due to a hose not being properly connected. The hissing noise you are hearing may be that the hose is not on tight enough. We recommend making sure the hose is reconnected properly, which should take care of the issue. If the vehicle continues to overheat after that, you may want to bring the vehicle to a certified ASE mechanic to have it properly diagnosed.

      Hope this helps!

      -BDP

  29. My 2004 ford explorer is running hot every time you turn the ac on and sometimes the ac does not have to be on. It usually does it on very hot days but I have changed the thermostat and the cap and flushed it out externally but it is still running hot any suggestions?

    1. Jasmin-

      Thank you for asking about your Ford Explorer. Your vehicle can over heat for a number of different reasons. Being that you have just replaced the thermostat and radiator cap, and had the cooling system flushed, the next thing you may want to check is if the water pump is circulating properly. Depending on the age of the vehicle and whether the water pump has ever been replaced, poor circulation of water/coolant would cause the vehicle to overheat. If you are still having an over heating issue, you may want to bring the vehicle to a certified ASE mechanic and have it properly diagnosed.

      Thank you!

      -BDP

  30. Hi I have a 96 Toyota camry and ive recently replaced my radiator because it had a Crack along the top and for a while that resolved my overheating problems then it recently came back to overheating so I changed my radiator cap and replaced the sensor and thermostat. Fan comes but does little help . Car temp returns to normal when I Rev the engine and have the heater on but as soon as I cut the cold air on and the a/c it immediately starts to overheat. When I look under the hood there is alot of steam blowing out from the reservoir overflow tube. Any help and or suggestions on how to fix this issue would be greatly appreciated. Thanks.

    1. David-

      We do recommend using BlueDevil Head Gasket Sealer for your Toyota.

      It sounds like the vehicle may be getting combustion/exhaust gases blowing into the cooling system and creating pressure. To give yourself the best overall chance of BlueDevil working successfully, in addition to the directions, you should remove the spark plug from the cylinder with the leak; this will be the spark plug from the cylinder with the low compression reading. If you are not sure which one that is, you may pull all of the spark plugs and will notice one will have a white-crystal-like substance on it and/or may look dirty; this is the plug you should pull. Leave that plug out for the 50 minute idle in order to relieve the pressure from building up and thus allowing the product to seal properly. Be sure to follow the guidelines for the proper amount to use.

      Thank you!

      -BDP

  31. I have a 2002 Pontiac Aztec. For about the last two and a half weeks, my car has started overheating. The first time, it had been fine all day, and I got in to go home, and turned on the heat, I felt air, but no heat. About twenty miles down the road, my alarm went off. Pulled over, and the coolant overflow resouirvor was boiling out water. A guy stopped and told me it probably got clogged, a flush would probably fix the problem, so I had it flushed, and it was fine a few days. Turned on the heat, overheated in minutes. Took it back, was told an air pocket, and it was running, heat full blast, with no problems. Next day overheated again, didn’t even turn the heat on. Took it back, this time told cap not holding pressure, replaced. Two days ago I used the defrost, no problem. Today sounds bad, indicator needle going up, I only live two miles from work. Looks like reservoir is very full and lots of sizzling popping sounds from radiator. Never saw steam at any time. Thinking after reading all these comments, I should have the thermostate checked. Any ideas?

    1. Sarah-

      Thank you for asking about your Pontiac Aztec. It is possible that you are getting combustion/exhaust gases pumping back into the cooling system.  You can use a “Block Dye Tester” to confirm whether or not that is the case.
      BlueDevil Head Gasket Sealer will still work if your vehicle is getting combustion/exhaust gases blowing into the cooling system and creating pressure.  To give yourself the best overall chance of BlueDevil working successfully, in addition to the directions, you should remove the spark plug from the cylinder with the leak; this will be the spark plug from the cylinder with the low compression reading.  If you are not sure which one that is, you may pull all of the spark plugs and will notice one will have a white-crystal-like substance on it and/or may look dirty; this is the plug you should pull.  Leave that plug out for the 50 minute idle in order to relieve the pressure from building up and thus allowing the product to seal properly.  Be sure to follow the guidelines for the proper amount to use based on the size of your cooling system.
      Feel free to contact our technical support line at 888-863-0426 with any other questions.

      Thank you!

      -BDP

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