How to Stop a Freeze Plug Leak

leaking freeze plug, engine blockHaving a freeze plug leak is pretty rare on cars today.  That’s because there is no movement of your freeze plugs and they are a metal seal rather than a rubber gasket or o-ring.  When an engine is built the freeze plugs are hammered into the plug and as they slide in the metal bends conforming to the freeze plug hole creating a really good seal.  Even though they are one of the best seals on your engine, it is possible to have a freeze plug leak.

In this article, we’re going to talk through everything you ever wanted to know about freeze plugs!

How to Stop a Freeze Plug Leak?

Like any leak, you can replace it or use a stop leak.  Due to the location of freeze plugs and the difficulty of installing them replacing them with a new metal freeze plug often isn’t an option.  Some manufacturers make rubber expandable freeze plugs but we don’t recommend using them as they often protrude into the cooling jacket creating a hot spot and usually don’t hold up very long leaving you with a leak again.  If you’re looking for a stop leak, BlueDevil Pour-N-Go Head Gasket Sealer is the right one for the job.  BlueDevil Pour-N-Go head gasket sealer is a nonparticulate sealer that won’t damage or adhere to anything else in your system except the leak point.  It’s permanent and guaranteed.

Why does your engine have freeze plugs?

Freeze plugs are installed to hopefully protect your engine block in case your antifreeze isn’t properly mixed.  If you don’t have adequate freeze protection the freezing water in your cooling jacket can exert over 100,000 PSI on your engine block which is more than enough to crack cast iron or aluminum.  A cracked block makes your engine just about useless as they are extremely difficult to repair.

Can I replace a freeze plug while my engine is in my car?

As we discussed earlier, most likely not.  First of all, even a leaking freeze plug is very difficult to get out of your engine block due to the tight seal.  The freeze plug will probably need to be drilled or cut out which can damage your engine block if you’re not careful.  Once you get the old one out your need to pound the new one in.  It takes a lot of force to press a freeze plug into a block so you need a straight shot, a big hammer, and a lot of patience.  Usually, having a good enough friend that is willing to hold while you hammer is a requirement as well.

Can I drive with a bad freeze plug?

If you have no other option, you may be able to drive with a bad freeze plug.  Freeze plugs rarely fall out or fail completely so they cause slow leaks.  As long as you keep your engine coolant full and your engine never gets hot, you could limp your car along with a leaking freeze plug although we never recommend it.  It’s messy and at any point could leak to your engine overheating.

You can pick up BlueDevil Radiator Pour-N-Go Head Gasket Sealer of your local auto parts stores like:

  • AutoZone
  • Advance Auto Parts
  • CarQuest Auto Parts
  • NAPA Auto Parts
  • O’Reilly Auto Parts
  • Pep Boys
  • Canadian Tire
  • Walmart