96 5.7 Vortec external coolant leak. Help please.

The heater lines go into the firewall just above this area. Another possibility is the intake gasket at the rear of the head. They always seem to go on these engines. My 94 Suburban did this. For weeks I was finding coolant dripping down the oil filer area onto the ground trying to figure out where it was coming from

How many miles are on the truck? If near 100K, it is probably the intake manifold gaskets. The base material of the gasket is plastic, and after many hours of heat it breaks down. The water runs off the back of the head, and off either the starter, oil filter or torque converter cover. Been there, done that, got that t-shirt. Mine leaked for a long time, then finally blew out the top of the gasket. I think it is leaking again because it smells like anti-freeze again. There goes a Saturday.

Thank you both for the help, it has 136,000 mi. When it thaws this morning I will go and check again, I initially ruled this out because the top of the motor is so clean, Would a pressure check identify this area (intake man) of leaking?

It should.

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Top of the motor, i.e. intake manifold, will be clean most of the time. It will leak between the manifold and the cylinder head, and run down the back of the head, along the top of the block and down to ground. If its the left bank it will run down the oil filter housing, if the right bank the starter will be wet. There are two other possibilities, I believe there is a small freeze plug on the back of the cylinder head, and there is also one behind and slightly above the starter. Chevy small blocks are not noted for eating freeze plugs, but it is still a possibility that cant be over looked. A mirror will be needed to get an good eye ball on the back of the head. Usually the manifold will stop or slow as the engine warms up, the manifold expanding as it gets hot. If the volume is as large as you suggest, and there is no coolant in the oil(if the manifold gasket gets bad enough it will leak into the oil galley as well) it may be a freeze plug. Also if it has been leaking any length of time, the coolant can groove the manifold (erosion happens to metal too, especially soft ones like aluminum) be prepared to replace the manifold as well.

Whitelightning

Thank you

One other thing, the new gasket set will also have new upper plennum seal that seals the two halves of the manifold. Unless you are having performance problems, don't use it, as the new gasket will probably leak. This is because the plastic half has adjusted to it's current position and gasket, and won't really fit again once it is removed. Buy an extra tube of the silicon "gasket in a tube" and save a trip back to the parts store.

phinq

Thanks, it's a blizzard and I found a reputable shop in town that for $400 the will replace the manifold and rocker cover gaskets, replace the quick disconnects and check the cooling system, we'll see how it goes and what the final cost is. I'll keep you guys posted for anyone in northern Ut.