jykchin

I have an 99 Grand Cherokee. On our last skiing trip, I turned on the car,and heard something that sounded like a spit ball shooting out of t compressor. Since then, it's been overheating and the interior vents wont change. Any advice?

upritexj

that sounds like 3 probs. any coolant leaks? a/c work? i assume you meant a/c compressor. i don't remember if the GC's use vacuum to control the mode doors but if they do check vacuum lines near firewall. vents usually default to defrost pos.

jykchin

Nope. no coolant leaks. no a/c work done. i was just trying to get the sound across....like a pressurized tube shooting off. And yes, the default is to the defrost [pos.

upritexj

gotcha, so r your vents in default pos? is it overheating all the time or only at a stop? if u have a mech fan maybe the clutch is bad and doesn' let the fan move enuf air at idle to keep your eng cool. wat eng. u got? your vents air vacuum operated hear any hissing noises indicating a vacuum leak.

Jeepin01

Check the water pump fan blades. My Xj overheated twice due to bad, worn down fan blades in the water pump.