Coolant Leak - Intermittent - 2002 4.3L Safari

[oneilldm]

I thought I had a water pump issue so I bought a new one and prepared to put it in.

I started to take things apart but got stuck when I couldn't find a spanner wrench to get the fan off. I decided to go ahead and flush the system in the mean time.

Before I drained out the Prestone Flush solution... I noticed it quit leaking. Hmmm...

So... I went ahead and finished flushing the system, refilled it with coolant, and decided to do a little more homework.

Since then, I noticed that it seems to leak when I run the AC. It's not condensation... it is dripping under the middle front of the engine... where you would expect a water pump leak, and it has coolant in it.

Anyone else seen this problem?

Thanks

[2002Safari]

My 2002 Safari is doing the same thing. It appears to be an intake manifold gasket issue.

I put a radiator pressure tester on it, pumped to 15 lb, in a couple minutes it dropped to 14 lb. Looked under the van and saw nothing. Pumped back to 15 lb and started to see a couple drips. I put the van on ramp so I could get a closer look. I could see antifreeze where the head meets the block at the rear of the engine. My thoughts were head gasket. I pulled all spark plugs for a compression test with plugs removed and fond 160 lb on all cylinders. Head gasket must be good, so I now need to look else where. The van is on a slight slope front uphill. My next move will be removing doghouse for further checking. I'll put radiator pressure tester on to see if I can more accurately locate the leaking. My expectations are either a hose cracked or intake manifold gasket asking for permanent retirement.

I placed an exhaustive how-to on replacing intake manifold gasket at viewtopic.php?f=4&t=6171

[oneilldm]

Thanks for the reply! GM's are famous for gasket problems due to their DexCool coolant.

Now... I may have a water pump leak... but I'll look for the Intake Manifold leak first. I hate to go to all the trouble just to find out I fixed the wrong thing!!!

Something I noticed about a year ago... my van started taking a couple of tries to start the engine. I replaced the fuel pump a few years ago and the filter is fairly new so I didn't think that was the problem. I noticed I was loosing some coolant and it occurred to me that it could be going into the intake manifold.

Often times these vehicles have the same problems so it's good to hear others experiences.

Thanks again!