Stimpy

I replaced my rear motor mount yesterday, and I'm noticing some vibration and noise I hadn't noticed before.

A brief history on the car: '99 I bought used with 90K. I replaced timing belt, timing belt pulley, timing belt idler pulley, timing belt auto tensioner, water pump, serpentine belt, and side motor mount last year at the same time at 138K. I replaced the front motor mount and tranny mounts a couple years ago.

I had noticed the "clunk" when shifting into reverse last year, figured it was time for a new rear mount. This morning I started the car and it sounds like it has a low whine to it that I have never heard before. Pedals vibrate, and the engine is a lot rougher when starting. At first I thought it had to do with the new mount being fresh and me just being used to a worn mount. But I couldn't get past the whine/vibration. Lifted the hood to check things out and I see some gray smoke coming from the left side of the engine around the P/S, alternator, serpentine belt area.

After shutting it off, I let it sit for a few minutes and started again to diagnose. Alternator seems to give off the most vibration/noise and seems to be the source of smoke, but I can't be sure because I don't want to spend more time than necessary diagnosing while potentially burning something up.

Suggestions? I made sure to support the engine with a jack when replacing the mount to make sure the weight of an unsupported engine wasn't going to affect other components, so I doubt I broke something that way.

My gut tells me something's up with the tension of the belt on the alternator, and somehow the new mount has the tension is such a way that it's putting a lot more pressure on the alternator than before. Time to replace serpentine belt auto tensioner?

victus1

The mount connects between the engine and the frame....so it wouldn't affect the tension of any belts. Perhaps you moved or shifted something out of place while lying on top of the engine to change out the rear mount?
As for the vibrations....what brand of rear mount did you get? Is it hydraulic? Did you install the rubber damper/isolator on top of it? Did you connect the vacuum line to the mount?

Stimpy

It's a beck/arnley mount, vacuum assisted and properly installed with the damper and vacuum line.

victus1

Try to diagnose it in steps. If the smoke is coming from the power steering area, then remove both the power steering and a/c belts....start the engine and see if the problem persists. This is easy to do. Just make sure you don't overtighten the ps belt during install.
If the problem went away, then add one belt at a time until you reproduce it.

Stimpy

Ok both belts removed today.

Sounds like the whine is coming from alternator belt. It wasn't whining when both belts were off or when just the P/S belt was on.

I replaced the serpentine belt tensioner today because it needed to be replaced anyway and I figured it couldn't hurt me rule out possible failed parts. Didn't help with the whining but it was worth a shot.

So, components on the serpentine belt to check on leaves me with the alternator and the A/C compressor. I haven't had any problems with the A/C or alternator…ideas on how to figure out what's causing the whine?

victus1

It's good that you replaced the tensioner. I replaced mine too. Hope you got a new ps and a/c belt as well. Try using a pipe on the a/c and then alternator to amplify the sound and try to listen on the other end which one is making the whine. This is how mechanics usually isolate sounds. Also try turning on the a/c from the controls to engage the clutch and see if the whine changes. But with the a/c off, nothing is spinning internally, so the only whine I can imagine from the a/c would be from the spinning bearings on the pulley....so it may be unlikely to come from the a/c.

Stimpy

well I took a deep look inside the alternator to see if there was anything obvious like broken parts or uneven wear. Brushes still look like they have some life left in them. I stitched it all back up and the whine doesn't seem too bad now. No smoke that I could see after the engine was nice and warm.

Speaking of smoke, I think it could be a small pool of P/S fluid on the block...cooking off as it gets hot. Apparently I have a small P/S pump leak -- that would explain the slow leak down the front of my engine block. Yet another repair to do!

So for now I'm going to conclude that I'm just being extra sensitive since the new motor mount. As far as I can tell, everything is in working order, so I will keep an eye on it over the coming weeks and report back. Thanks for your help Victus.

3.2TLc

Take care of that PS leak, before it causes problems with the pump.

victus1

Perhaps you have that common O-ring leak from the ps hose. Do a search for details on how to replace the O-ring. You need to get the special one from the dealer.