It appears that my upper intake is leaking. The first one failed at 102,000 miles and now with 202,000 it is time to replace it again. The strange thing is that I can't actually see the coolant leaking out of anywhere. I can see that it has been collecting on the lower manifold, but I can’t see where it’* been coming from. It doesn’t seem to be burning coolant like it did the first time, so no big white clouds of smoke from the exhaust. I had to add some coolant to the reservoir, so I think I’ll work on it this weekend before it causes more problems. Does anyone have experience with the aftermarket intakes, or other advice about this problem?

Thanks

aftermarket is a improve desigin from the stock one so it will prevent it from happening again

I just replaced the intake on mine

although not as bad as yours judging by the picture...

I replaced mine with a Dorman off ebay... so far so good, but its only been a little while

Take your car to a trusted shop, have them run a cooling system pressure test.
You'll see where it'* coming out... judging by the location, I'd have to guess the intake gasket is at fault. if it was the typical intake failure you wouldn't be loosing it like that outside.

Is there anything in the oil? milky filmy? exhaust smell sweet?

I also noticed you have green coolant... drain that out and make sure it'* dexcool
You don't want anything to rust prematurely

fwiw - the gm replacement *is* improved over the stock ones, and you shouldn't experience any problems with them... i think the general concensous lands the revised manifolds working into the system in 99 - so i think there'* a good chance that in 5 years the bad ones have been removed from the system

matt

Any idea of what the casting date is on the revised manifolds? My 99 is stamped 1/XX/99. No leaks yet; still nervous though!

The casting date on mine is 12/98. I just picked up a Dorman aftermarket unit at Checker Auto Parts for $149 . Once I have it all apart, I'll take some pictures and post them. It should be a pretty easy job if I rember right.

My 96 had a leak exactly like yours. I installed stant cap and 1/3 bottle of
Bars leaks and it has been dry ever since.
Bought a replacement 01 gm manifold off ebay as insurance.
If it leaks again its out of there.

i don't think much of anyone is completely sure when the change went into effect. i suppose i could always ask the aulity manager over at flint. hmmm...

i'll see if i can find out...

matt

Go with the Dorman intake. No question about that one, and it'* alot cheaper.