noise from under dash

If this helps, I had the exact some problem on my 95 S15 Jimmy 4x4. It turned out to be a leak in the cooling system that introduced air and perhaps even as far as the heater core (I believe that's what's actually making the noise behind the dash). Anyway, I was able to find a leak on the high side of the rad - I threw in a new rad, changed and bled the system fluid and have had zero issues since.

I hope this helps? The worst case scenario would be that the heater core itself is leaking. Is there any moisture on the pass side floor or under hood in same location? Pray it's not the HC - it's not a super fun job to re/re.

Thanks. Andrew.

I think what you just said is exactly what's wrong. I'll start checking mine for some kind of air leak.

Thanks. Yes, mine is Chevy 96 S-10.

Check the message Wierd Sound from JBDragon on 11/08/2007 in this newsgroup; seems to be the same symptoms.

There was a discussion on this very issue on one of the other chevy truck boards. I chimed in because I was experiencing the same thing with the '01 Blazer I bought this past summer.

I made sure that my cooling system was completely full... parked the vehicle on some ramps so the radiator was higher than normal, warmed it up and added Dex-Cool to both the radiator and the overflow tank. Then... and I think this was the thing that clinched it... I installed a NEW radiator cap.

This has cured my problem. Your mileage may vary.

Mark '01 Blazer LT

Good posts. Thanks.

Sorry this has nothing to do with your problem (but maybe it does!).

Friend of mine at work was telling me that she went out to her van to get some stuff and she found a racoon foraging around in there, scared the s*it out of her!!! Maybe you got a squirrel living in there!!!

Hahaha H.