Coolant leak under the exhaust manifold! Help!

[xfreemanx]

Coolant leak under the exhaust manifold! Help!

My car is a 94 Corolla Gli. I had coolant leaks before and have fixed them (worn out drain plug gasket - fixed with teflon, leaking water pump - replaced). Recently, I changed the coolant on the car. After a few days of regular use, I almost got an overheat. Checked the radiator and it was almost dry. I checked for leaks in the radiator, hoses, water pump. Didn't find any there. I took a peek under the engine and discovered that the leak was coming from under the exhaust manifold. Its not exactly on the manifold connection. The leak was coming from two small circular "caps" (1 inch diameter) on the engine block? What are these for? How can I fix the leak? Should I just clean the caps and put hi temp epoxy on it? How can i DIY repair this, is there a kit?

Thanks.

[tashirosgt]

I think the caps you describe are called "freeze plugs". They are thin and can be removed and installed in your engine block with hand tools, if you have room to get to them. The standard removal technique is to use hammer and a screwdriver or punch into them an knock them "askew". They bend and are pushed to one side in the hole where they fit. Then they are pulled out. A new plug is coated with a sealant ( I don't know a brand name, but someone at an auto parts store could tell you). Then it is hammered in the hole. You can use a dowel or something that hits evenly along the rim of the plug.

You might not have room to do these operations. If that is the case you (or your mechanic) will have to take enough things off to get at them. Also there is a slight chance that in attempting to remove them you might hammer them so the fall inside the engine block out of sight. I have never had a leaking freeze plug. If they slightly popped out of the holes, you could try to tap them back in. Perhaps some other forum member has tried repair rather than replace.

[JohnO356]

I've changed a lot of freeze plugs and never had one fall inside the water jacket. If you're worried about that I guess you could drill a hole in the plug and pry it out with a screwdriver. Also, I have never used a sealant. The best thing I've found for driving the new plug in is a socket very close to the diameter of the plug. The purpose of a freeze plug is to protect the block should your coolant freeze (a very real possibility in your area, LOL). The plugs pop out to relieve the pressure that builds up when the coolant freezes.

They also make a plug like the lid on a thermos bottle. Easy to put in, but should only be used as a temporary fix.

[Flashmn]

Freeze plugs are there due to the casting process of the block, so the reason for them is dual. They have screw in freezeplugs, that work like a rubber plug, you put it in and then twist the nut to tighten them securely and they work pretty well too.

[cuzman]

AS far as im aware a (freeze plug) welch plug in australia is only ther due to the casting process....
Idont reconment drilling them as you will get metal shavings in ya cooling system with can affect the pump and also jam the thermostat...only a possibilty but thought i might bring it up..
ANy bodie got a pick of a freeze plug....as im currious lol