I took off my oil cap and noticed a yellowich type foamy substance and what looks like water inside of the oil filler neck.I called the dealer and they said to keep an eye on it. I cleaned up the area and about 2 weeks later the stuff showed up again. I have a 2002 Tahoe 5.3 and I have not encountered this with it. Has anyone else ever experince this and what do you think this is?Thanks

 

Seems to be pretty normal condensation. Most of us experience it in the winter..I wouldnt worry about it, but do keep your eye on the coolant level.

 

I agree if you have a 160 stat and take short trips in the cooler winter weather you might see this.

 

i had a similar situation with a pontiac montana and i discovered the yellowy foam when the valves start clacking. it was in fact coolant leaking into the enigine oil.

 

sounds like the intake manifold gasket is leaking. I had the something on my wife’s grand AM. see if the coolant is a little greasy felling.

 

There is no water path to the intake manifold on LS engines.

 

i agree with CrazyBosnian sounds like condensation. an aluminum block produces more condenstion than the iron block that bein the reason your tahoe does not have the same problem.