leaky core plug (frost plug)

[Flanders 46]

Two core plugs on the pass side of the engine (one above starter, the other next to the engine mount) are seeping coolant. I don't like the small puddles under the car because of them :)

 

Any easy way to replace them without taking the motor out? The one above the starter is accessible with the starter out, although I'm not sure how much leverage I'd have to punch it in and replace it.

 

Any other alternatives?

[Big Secz 26]

I assume by "core plugs" you mean freeze plugs? You may have better luck just taking some RTV sealant and putting around the edges of the plugs. Also there is a threaded plug that sits back by the starter. This is a coolant drain plug back by the starter, there is one on the passenger side and driver's side. You may want to check this plug to see if it's leaking. If it is, you will probably have to pull it out, just unscrews using a socket, and put some teflon tape on it and reinstall it. But if it's just a freeze plug, I would try tapping it in a little more and sealing the edges with RTV.

[Mister69 10]

I had a couple small frost plug leaks after installing my engine. I dreaded the thought of pulling it out again just to fix something like that. Instead I went to the GM dealer and picked up a package of "Cooling System Seal Tabs". I crushed up one in a glass of water and poured the mix into my radiator. Took the car out for run and the leaks were gone and that was 3 years ago. You add so little of this material that there's no chance of plugging anything up.

 

Give it try.

[Flanders 46]

thanks for the tip -- I'm now debating pulling the engine anyway, but if I don't pull it I'll see if I can find something like that!

[69gmachine 15]

I assume by "core plugs" you mean freeze plugs?

 

Call it a pet peave, but Flanders is absolutely correct in calling it a core plug! The holes are there to allow the casting sand core to be removed from the water jacket after the block has been cast. They are then machined and plugged to seal the water jacket. You should never rely on them to pop out when the coolant freezes, as often times the block will crack first.

[Big Secz 26]

Call it a pet peave, but Flanders is absolutely correct in calling it a core plug!

 

 

Sorry that my using the term "freeze plug" makes your skin crawl. But freeze plug, frost plug and core plug all mean the same thing. Every professional resource that I have read (magazines, books, shop manuals, etc.) more commonly refer to them as "freeze plugs". Perhaps your choice of which term to use can be influenced by geographic location. To each their own.

[Flanders 46]

:) my mechanics class waaaaaay back in high school called them core plugs, so I was always a bit confused when I kept reading articles that mentioned "frost plugs". We all know what I'm trying to talk about, so it's all good!

 

I'm hesitant to try and tap them in a bit more, just because I don't want to make the leak any worse. Two of them are right over the motor mounts so this is one more reason to pull the engine out before winter.

[LoneWolf2U 136]

If your going to remove the engine, then get a full expansion plug kit and replace them all at that time.

If one is seeping, it will not be too long before another one starts.

[Flanders 46]

adding a picture to this thread too. I love pictures :)

 

Very leaky core plugs! A new set of steel ones is in the mail.

 

 

[CandyAppleRed 10]

It'll take a couple of tubes of RTV to stop those leaks!

[Max Power 74]

Technically, they are core plugs.

 

And I would never recommend using sealer on any leaking core plug. They leak because they are rotting out from the inside. Only fix is replacement, and if you can get a camera in there, you can punch them out.

 

If you punch in on one side, usually the other side will come out far enough to get a pliers on there and pull them out all the way.

[Flanders 46]

yessir! That's what I'm doing with the engine out :D