I just started to notice this in the extreme weather that we are having - below freezing temperatures, so it could be just the cold weather.

What is happening - I hear this whistling/whinning noise at specific RPM's. 2800 and 3600. At any other revs it's not doing anything. It doesn't matter if the car is moving or not.

In terms of performance there is no difference. I have several suspicions:

- timing belt tensioner - they only have 50k miles on them, but it's been 7 years since the last change.
- alternator - I recently changed the battery in the car - would that have anything to do with it?
- vacuum leak - where from though???

I guess I'll have to wait for the weather to warm up a little bit and see if it's still doing it. But is there anything else I can check? It almost sounds like a supercharger whine.

 

Excuse me for what seems like a dopey suggestion, but you could try turning off your heater/defroster fan and see if the noise disappears. My blower motor started making intermittent noise with the colder weather — sort of a whining hum that had me worried at first that it was some engine melt down.

 

I tried turning everything electric off - no effect.

 

Turbo, non-turbo?

 

1994 non-turbo, automatic. 165,000 miles. Timing belt last changed at 120k.

 

Whistle only at 2800 rpm and 3600 rpm specifically? Not in between? It does it when Gear selector is in D or N or P?

 

Not in between. It does it at 2800, stops at 3000, and starts again at 3600, stops after that.

I tried it both in P and D.

 

You are sure it is not the radio? Have you tried to pull any codes?

 

I haven't pulled any codes yet. Like I said, there is no impact on performance, car drives as usual.

I don't think the radio can create a whistling noise in the engine bay.

 

I don't think this is vacuum related. Timing Belt tensioner and alternator -- they don't do anything specific at those set rpms and nothing in between. You should try to pull codes, including the A1 socket (transmission).

 

I looked over the engine bay today. The only thing that was slightly outside of normal was the transmission fluid level. After 15 minutes of driving it's only at the MIN mark on the HOT side. But that should be quite normal for the winter.

I have a day off work tomorrow so I'll have some time to do more checking. Anything else I should check?

 

Put some more fluid in the transm, and see if the whining goes away. But do pull codes from A1, A2, A3 and A7.

 

The only error codes came from the ABS, A3
-312
-211
-212
-213
-214

As far as I know these are jsut the ABS sensors. The ABS is working fine, I don't know why it's giving me the codes.

 

They seem to all be related to gunk-ed wheel sensors.

No codes on A1, A2, A3 and A7? Whining noise still there after adding transm fluid??

 

Nope. no other codes. I haven't added fluid yet, and I'm worried about adding it. When it's warm it goes right to the top of the HOT mark. Only when it's cold, like now, the fluid level looks low.

(as for color - it is pink, I had it flushed 6 months ago)

 

You're confusing me -- earlier today you said that after driving for 15 minutes, transm fluid was at the Min mark of HOT. No?

If the fluid is at the top mark, of course, don't add more.

Pink color is good. Did the fluid smell burnt?

 

It's not burnt. What I meant was - when the weather is warm (70degrees) the transmission fluid is right at the top mark of the hot side.

But now, when it is 20 degrees outside, the fluid level is not even reaching the minimum mark on the hot side. I don't even bother looking at the Cold side of the stick.

 

Outside / ambient temperature is irrelevant in checking Transm fluid level. The only thing that counts is that you should measure it after driving for a period of time, stop, let the car idle, and go through all the shifts, then put the selector to P and walk outside and check the level. That's the reading you should report back.

Next thing I would do I would start driving and listen for that whistling/whining sound in relationships to shifts: 1 to 2, 2 to 3, 3 to 4, and 4 to TC lock-up (this is when rpm drop). Let us know at which shift-points you hear the whining/whistling.

 

Ok I will try that. But I have a feeling the sound is coming from the other side of the engine, where all the belts are...I may be wrong though.

 

That to me sounds like a bearing whine. Since you have the noise whether you are in P or D, it cannot be related to wheel bearings or axles, or anything that doesn't move when you are still (P).

You said that you hear the noise at a very set /narrow specific rmp: 2800 - 3000, and 3600 even. In no other rpms. Belts, i.e. bearings on all belt driven things would whine at much wider range of RPM.

Try to read the noise in relationship to specific shifts. If you can tomorrow get under the car and make sure that transm wiring harnesses are not loose/corroded.