Hi there I have a 1998 chevy k1500 4wd with towing package, and I have a coolant leak somewhere on the backside of the engine that can not locate. There is no oil in the coolant or coolant in the oil, does anybody have any clues what the problem could be?

 

Most likely it is a external intake leak

 

The thing that has me confused is that it only does it when it is in the cooldown process, and as far as i can tell it doesnt do it when it is running.

 

if you are having to add coolant from time to time, you have a leak.

I never saw any coolant leaking from my 2000 model 350 engine, the coolant was leaking into the intake manifold gaskets. If not corrected it will get worse and can ruin your engine.

 

It could also be a soft plug on the back of the engine. I had one leaking on my 350, and it was behind the bellhousing, and I had to pull the motor to fix it. It was a MAJOR pita.

 

I have the same problem with leaking on my 98 350. The coolent drips off of the bellhousing very slow. Could you explain more about the (soft plug)? What is a soft plug? Seems to loose water on cool down also.
Thanks

 

check throughly around the intake manifold, as this was a very common issue with the 97-98 350's particularly around the top rear of the engine.

EDIT: also check the quick disconnect for the heater hose as that is also a very common leak area

 

Get a peice of card board and put under the vehicle when you park it. This will tell you if you have an external leak and the general area it is in. Then with a good light and a mirror you might locate it. It would be good if you could put a pressure tester on the system. If you dont see anything outside my bet would be manifold gaskets. These engines are famous for leaking there. The "soft plugs" are welch plugs (sometimes called freeze plugs) they plug the holes used to remove the sand when the block is cast.

 

I think he is refering to a freeze plug. There is one on the back of the engine and there are i believe 2 on each side of the engine. they are brass plugs about the size of a silver dollar. If the one on the back of the engine is leaking you have to pull the engine out to fix it.

 

Thanks everyone. I used the cardboard and it is dripping off the bellhousing. Will a pressure test locate the leak?
Oh its a 1998 w/70,000 miles