All,

My son's 95 850 Turbo has developed a noise that I could use some advice on. The noise is sort of a low pitched whine/moaning sound that seems to be coming from the rear end. The rub is that it only occurs after the vehicle has been sitting overnight or longer, and it only lasts for about 2-3 blocks then goes away. It will not come back again until the car has been sitting overnight, then it moans for about 2-3 blocks and goes away. It does seem to be speed related as it changes pitch a bit as you speed up.

Car runs smoothly, no vibrations, and it is quiet as a church mouse after the first few blocks. I thought rear wheel bearing, but I am not sure as the noise goes away.

I'll try and check today to see if it makes the nosie if the brakes are applied.

Any advice greatly appreciated.

Glenn

 

My guess would be calpier hanging up

 

BINGO!!!

I was a sticky caliper. I took apart the rear wheels, cleaned and adjusted the parking brakes, took the brake pads off, greased the calipers and the slide pins, put it all together again, and it is quiet as a church mouse.

Many thanks,

Glenn

 

Ok, I spoke too soon. Noise is back even after greasing rear calipers. Actually I did some more investigating and it sounds like the noise is coming from the right front or right center of the car.

It is a loud groaning sound that occurs only when first moving the car after it has been sitting for a few hours or more. It only occurs when moving forward at 15-25 miles per hour and only when gently accelerating. Additionally it only lasts for about 1/4 to 1/2 mile and then completely disappears until the next cold start.

Today when it did it, I put the car in neutral and revved the motor a few times. It kept making the sound, but it seemed only at certain RPMS. I then put it back in gear and accelerated briskly and the sound went away. I returned to accelerating gently and the sound came back. If I took my foot completely off the accelerator and coasted there was no sound until I gentyly accelerated again.

Since it seems to only occur at gentle acceleration after sitting cold, seems to be RPM dependant, and seems to be coming from under the right/center of the car, and then goes away after about 1/4 mile or so, I'm thinking some weird exhaust resonance that goes away once the exhaust system warms up.

Any ideas on what to check? I'm going to grease the front calipers just in case, but I'm puzzled,

Glenn

 

How many miles on the car? If more then 150K, it could be tensioner or idler pulley.

 

Car has 173K on it, but the timing belt, timing belt tensioner, timing belt pulleys, serpentine belt, serpentine belt tensioner and serpentine belt pulleys, along with the water pump were all changed less than 1500 miles ago.

Glenn

 

Try adding some belt dressing....I know it says don't apply to serpentine belts, but a little won't hurt....see if that makes the noise go away. Could be a bad belt, tensioner, or...

 

put the car on a ramp and check out the exhaust system for any loose/missing grommets or mounts. It's possible for different noises to resonate at different RPM's throughout the exhaust.

Is the car an automatic or manual, If manual you could have a throw out bearing problem or something like that in the clutch for the tranny.

-Mike

 

Tired the belt dressing, but it still did it this morning. I'm going to put it on ramps for an oil change this weekend, so I will check the exhaust system end to end. Oh yes, the car is an automatic

Glenn