Key on ACC position, weird noise from behind the dash..

[Dylan JZ]

At first I thought this may be a heater core related, but AFAIK my valve has been closed since day one of owning the car, and the solenoid is not connected (no heat either obviously).

What I want to know is what this strange noise is.. it only occurs when the key is in that position and maybe a few seconds after start up (goes away after like 15 secs on ACC). It sounds sort of like burping/gurgling air noise, and only happens when the car is cold, like in the morning for instance. My floor is not wet at all, my windshield doesn't fog on start up, no coolant smell inside, and I haven't noticed anything else odd. I am losing a tiny bit of coolant over a long period, but it's been that way forever because the twins burn it. I have read to not really worry about it, that it is most likely just air in the system (if it's related to that at all), but I ask because I thought most if not all of the things folks talk about are when the engine is running versus not.

Ideas?

 

[jetjock]

Could be a climate control servo. They tend to go open loop with age and begin to chatter. If changing the temp set point to something other than where it's normally kept helps than that's likely the problem. Hopefully not as they're neither cheap nor easy to replace.

 

[Dylan JZ]

Interesting. I read elsewhere that it may be something along those lines since the ACC specific would tend toward something electronic.

I'll take that advice and see what happens, at which point Ill report back. Thank you, JJ.

 

[Dylan JZ]

well, it did it again, only this time it did it after the car had been on and driving around for about 45mins.. I played with the temp buttons and cycling on and off, and tapping the gas with no noticeable change in the noise.

I did however feel exactly where it's coming from. I grabbed the black block in the pic and the noise/vibration is coming from directly above it.. I still don't believe this is coolant system related, and to the touch it feels mechanical in nature, so is that the general area for the solenoid or something else that would cause this?


(looking up under the center of the dash from the passenger side floor)