Odd noise from front end/engine...

[luvmy02impala]

Hello,

I was driving my 90 Dakota home the other night, and I heard a wired noise from the engine.front end. The truck has 78k miles, 4cyl, 5spd setup.

I would say it kind of sounded like a fan belt shreak. I replace the fan belt less than 1k miles ago. There is only 1 belt, from the crank pulley to the alternator. I don't know if it was the alternator, because the interior dash lights and headlight did not dim or get bright everytime I pressed/released gas pedal.

When I heard the noise, I put the truck into neutral and hit the gas a few times. The engine was still running and the noise did not change as the engine rev'd & recovered. I put the truck back into gear and the noise was still there. I was going about 40/50 mph, then it happened again at 65 mph.

I think it stopped when I tapped the brakes. It was cold out, so I thought it was something weather related, but now I do not know. It was not consistenly going, it was on/off again for about 20 minutes, then went away for a bit.

Could a brake shoe/caliper be frozen against the rotor? The front wheels did not appear to be hotter than normal. What about the rotor bearings?

The truck has not been pushed on the highway in a while (just got the truck a few months ago). But it was used on a normal basis, both city & highway driving.

Any suggestions? Maybe I could look for something to fix myself. It is not a daily driver, so I have the time to pull it apart and investigate. I am thinking it is not engine/trans related. Hmmm, what about rear pumpkin?

-TL

[rhandwor]

I would remove the belt and spin the idler pulley by hand. If rough or it makes get a new one. Auto Zone sells dayco idler pulleys. I would also check the alternator bearings for noise or roughness.

[luvmy02impala]

It it was belt related, wouldn't the sound been affected when I dropped it to neutral and hit the gas pedal a few times? There was no change in sound when the gas pedal was pressed and released.

-Tom

[rhandwor]

Bearing noise usually changes depending on the speed. You can jack up one side at a time remove the caliper and tie it up. Then spin the wheel by hand a bad wheel bearing will feel rough and make a noise. If 4wd put it on jack stands and remove both front calipers. Run it in 4wd and you should be able to hear it. You just have to try a few things until you find the problem.
The front brakes can make noise also. It might take you an hour or two until you find the problem. If you have a dry front wheel bearing you maybe able to repack them.

[luvmy02impala]

As it got colder, the squeal got louder and more constant. I believe now it is the wheel bearings (it is a 2wd extended cab). I know they were replaced about 2 years ago when brakes were done (rotors cut at that time, not replaced) by previous owner (my uncle). Truck did not get much use after that.

Should I changes the bearings, or just have them repacked? Isn't there both inner and outer bearings per front wheel?

Thanks for all help.

-Tom

[rhandwor]

Depending on the funds available I would install new ones if you have money otherwise remove them and clean them. Replace any rough bearings then repack and install them.

[luvmy02impala]

Had it repaired. The bearings were shot, since the grease dried up. The inner sleave of one of the bearings froze to the spindle on one side. The pins in the bearing were shaved and worn. The spindle only had minor damage. The shop was able to smooth the spindle and put new bearing on with no lateral movement with the new bearings on the spindle.

They investigated the brakes since could have been a wear tab rubbing. But it was the bearings.

-Tom