P J Moran

I have carefully monitored my new engine for leaks and have found two coolant leaks. One is around the water pump bolts. I can fix that by pulling them and reinstalling them with silicone on the threads (right?). The other is at the very front of the passenger side cylinder head. It's making a fair mess, and I want to stop it.

I am running Edelbrock heads on a GM short block. I used Fel-Pro head gaskets (with the copper ring for aluminum heads) and (at least thought) carefully torqued all of the bolts in the proper sequence to the correct torque. I also decided to use the new Dex Cool anti-freeze and distilled water.

I seem to recall a post from Vader that indicated that this stuff is more prone to leaking. This might be supporting evidence, but a well built engine shouldn't leak, right? What I'm wondering now is:
1) Should I try some of that "leak stopper" stuff you pour into the radiator? If so, do you recommend any particular brand? If not, why not?
2) Should I switch back to "regular" antifreeze? Does that have any chance of sealing the leak?

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'87 IROC 5.7l TPI - original owner!

Ed Maher

No, for leaks like that you want to fix it right. I only use stop leak for *minor* radiator leaks, and then only when i'm too poor to get a fresh radiator.
It might not be the head leaking, it could be the intake at that corner. I'm not saying it isn't the head, but when you start taking it apart, be careful and you'll be able to tell if it is coming from the intake gasket or not.
Also keep in mind that if is leaking like that outside the engine, it could leak inside as well, and antifreeze in your oil = no more engine.
...ed

scoob8000

well i prefer not to use leak stoppers, but if it is a must, use the prestone stuff in the clear bottle with the black goo inside.. it along with the liquid it water pump lube and the pellets clog up the bigger leaks...

FJK

Relative to Dex Cool coolant, you may have read something into Vader's comments. Dex Cool can deteriorate gaskets that are not designed for that type of coolant. This would be more of a long term effect. Since it sounds like you have a new engine, you have leaks for reasons other than the type of coolant. The one by the cylinder head could be the intake manifold gasket leaking by the water passage. Why not clean all surfaces & pressurize the cooling system to determine the exact source of the leak.
Regards, FJK

P J Moran

Ed,
There's no water in the oil, so I'm "lucky" so far.

FJK,
Good idea, but how do you suggest pressurizing the system? You can't poke around on a hot engine, and by the looks of the stains, the coolant is evaporating quickly as it leaks so you wouldn't be able to see any wet spots.

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'87 IROC 5.7l TPI - original owner!

scoob8000

use a rad pressure tester, you can get one at most parts stores or sometimes borrow one.. essentially all it is a little hand pump with a hose that runs to a special rad cap with a gauge, pump it up to specs, watch for leaks, and watch for rpessure drop..