Hi I have a 91 LE with 141.5k miles. I noticed recently after I turn off the car I get a rhythmicc noise. Sometimes it happens 5 seconds after the car has been turned off. I'm not sure how to describe the noise. It definitely has a rhythm/pattern to the noise. It slowly winds down and then stops after 5 - 10 seconds.

It sort of sounds like there is something moving in a circular fashion (kind of like a dryer drum) and there is something that brush or slides every half second or so. I haven't been able to isolate exactly where it'* coming from. It'* coming from under the hood obviously.

At first I thought it might have been a spun bearing, but I'm not experiencing any knocks. So it probably isn't that. But that was the first thing that came to mind when I heard the noise. Like I said the odd thing is that the car is off.

The other thing I noticed is that the car has recently started to "huff." After about 30min - 1hr of driving, it goes away. I thought it might be loose belts, but they seem fine. I'm not sure if the two things are related.

I'm sorry for the lack of description/words. I'm actually half way decent with cars. Obviously, I've hit a section that I don't know

TIA

You don't have "Spinners" on that car do you???

It might have something to do with the Cooling Fan(*). While the car is in PARK, and the engine and A/C ON, open your hood and see if you hear that noise around the fan area. Or, when the engine is OFF, try spinning the fan(*) to see if you hear that "noise".

mine did this too. it was the cooling fans. if you activate the diagnostic mode on your car, the fans should com on. if that is your sound, its all good! i dont think it would be a spun bearing. i dont think it would take that long to wind down would it?

Nah and if somehow it did you'd surely know when driving it. I'd go with the fans too.

You can also test this by shorting the A and B terminals on the ALDL connector. Just because the fans are running, doesn't necessarly mean they are the problem. Plus you will hear it from in the car, so you will know for sure. But I have never had the fans continue running after the car shut off.. so I am skeptical of that being the issue here.


-justin

You are correct in that the electric cooling fans in late model GM cars turn off as soon as the engines are turned off. But with some manufactures back in the 70'* and 80'*, the electric fans did NOT turn off when the engine was off UNTIL the water temp reached somewhere below 190 degrees. This led to a lot of people to think that the car was still running after it was off. This was really evident in the summer time when walking thru the shopping mall parking lot.

I'm not suggesting they're actually running when he turns it off, but the only thing that stops them is friction and you've gotta wait for that. Also, there are a lot of things under the hood that can make noise but not many that'll make a "rhythm/pattern" and "wind down" after 5-10 seconds. Also I doubt a solenoid or stepper motor would sound like "there is something moving in a circular fashion" with "something that brush or slides every half second or so." I'm not saying its definately the fans because following a noise description from someone on the internet is hit and miss at best...but it sure matches up pretty well..

I guess from here the best suggestion would be for him to drive the car as he normally does then ask a friend to shut it off while he has his head under the hood. That should answer a lot.

The shorting the A and B terminals [the procedure to extract codes], will turn both low and high speed fans on.


-justin

Thanks for the replies! I haven't been able to reproduce it yet. I'm going to try the short method. Where and what is the ALDL? I will research this later when I get a chance, but feel free to post it if you like

Thanks everyone!

[quote="Black Mammoth"]Thanks for the replies! I haven't been able to reproduce it yet. I'm going to try the short method. Where and what is the ALDL? I will research this later when I get a chance, but feel free to post it if you like

Thanks everyone![/quote

ALDL is right under the driver side steering colum