somnoboy

'92 LS. After my timing belt change (done at 90K at a dealership), my A/C, when turned on, seems to make a louder, sort of labored, whining sound. Could this be some sort of misalignment? Serious? The A/C still seems to work fine, but I'm just worried if I'm putting some sort of stress/strain on the belt assembly.

steve2006

Hi,
As far as I know the AC compressor is not disturbed during a TB replacement, the only thing that is removed is the serpentine belt which amongst other things drives the compressor.
Was the serpentine belt replaced at the same time? If not has it been refitted the opposite way around from it's original direction,this may cause noise due to belt wear patterns.
If the belt was replaced is it the correct one?
The belt is auto tensioned although very tight there should be a little movement in the tensioner.

somnoboy

Hi Steve. I have no idea if the serpentine belt was replaced. I'm thinking of taking it to a different Lexus dealer to have them look at the thing again. The dealer that did the Timing belt replacement is, in retrospect, pretty dodgy. I don't go there anymore.

Perhaps someone else has an idea on this?

bornpeace

i will check serpentine belt before making any other call. "Somnoboy" is correct TB got nothing to do with AC compressor. if ur hand, take the belt out and put it back and align correctly, follow the diagram under the hood beside the grill.

bornpeace

I meant to say "steve2006" and not "somnoboy"

somnoboy

Ok. I'll give that a try before calling a dealer. Thanks for the helpful response.

somnoboy

Hi guys. I just checked the serpentine belt and I visually verified that the belt is installed according to the diagram under the hood.

What's next?

deanshark

What steve2006 is saying about the serp belt is that it may have been put on backwards from the way it was. (Flipped front and back) Although it is routed right the wear marks that were in the back are now in the front, and vise versa. When I did my TB I did take off the AC compressor, I think it was just to get to another bolt or something. What you should do is look under your hood and have somebody turn on the AC and listen to where the whining noise is coming from, you should be able to pinpoint it from there.

Kansas

An automotive stethoscope is the best way I've found to pinpoint noise sources but be very careful using one under the hood with a running engine. These things cost only a few bucks at auto parts stores.

somnoboy

Thanks Dean and Kansas. I'll have a looksie (or listen) and I'll post the results. Thanks.

somnoboy

A few things:

1. After running the engine with hood open, the sound only appears when a/c is on, and to my totally untrained ear, it sounds like it is coming from the a/c compresser wheel (which I assume is the highest (closest to your face when looking down) wheel in the serpentine belt assembly.

2. I checked the parts list on the invoice from the timing belt change, and there does not appear to be any mention of a serpentine belt. Just a timing belt and water pump (and associated bits).

3. Is there any way for me to visually tell if the serpentine belt was put on backwards? Someone mentioned wear marks?

4. If it is the case that the serpentine belt is backwards, is there any way for me (a novice) to easily take off and reinstall the existing serpentine belt? (Preferably without tools?) If not, I do have access to a local mechanic nearby, who, while certainly not a Lexus expert, can probably perform this if this is simple and I give him informed instructions.

5. So long as the A/C is off, am I correct in assuming that whatever misalignment there is in the serpentine belt is not straining/stressing the engine in any way?

Thanks in advance to everyone who has been chiming in on this. You guys are a great help, especially to a non-expert like me.

bornpeace

"Somnoboy" i am not sure abt 92 LS but if i am right the AC compressor is on the bottom driver side and not the way you describe, which means it wont be close to your face unless you take radiator and fan out and drop ur head in. The highest pulley when you open the hood will be the steering pump pulley(passenger side) and little pulley under the radiator hose (toward center of the engine)
If you take the engine undercover the close to ur face pulley will be AC compressor(driver side), crankshaft(middle), and alternator(pass. side). Just above(between) the crankshaft and and alternator will be the tensioner pulley.
serpentine belt has two sides; one is flat(outside) and the inside is lines(tooth like). Make sure the lines on the belt are aligned with the lines on compressor, steering, crankshaft, alt, and the little pulley. The flat side should be pulling tensioner and fan clutch pulleys.
To remove the belt u will need i think 12mm or 14mm wrench(not sure) put the wrench on the tensioner pulley bolt, dont open just push the wrench down and the belt should come right off. When the belt is off, try to rotate the tensioner pulley and any other pulley that can rotate and listen to the noise, it may not be your compressor. Inspect your belt too. Follow the diagram to but the belt back. Turning A/C on put a lot of tension on the belt, if one of your pulleys are bad they will make noise.

somnoboy

Ok, let me have a look and noodle over that detailed post. Thanks bornpeace.

somnoboy

Could it be that after 9,000 miles, the serpentine belt has "broken in"?

I just drove around in the car for a while, cycling the A/C on and off. Driving it now, the sound from the A/C doesn't sound all that loud at all, at least, not from inside the car with the windows rolled up. I remember that immediately after the timing belt change at 90K, the A/C was definitely making a belt-related sound. I didn't have time to deal with it then, so I thought I'd look into it now, 9,000 miles later. But now, everything seems fine, more or less.

Assuming that the serpentine belt was reinstalled backwards, could it be now that 9,000 miles later, after the belt has "broken-in" and reseated, that everything is now as it should be? I believe that the serpentine belt is the original one, installed on the car at the factory in 1992.

Even if the belt has in fact reseated, should I replace it on my own because of its age?

deanshark

If the serp belt still looks good (no rips or cracks) I wouldn't change it. If it looks old and brittle, then yes, change it. Things like this don't usually fix themselves, they usually get worse, but if it seems to be OK now, I would wait till your next oil change, explain to them the sounds you had and have them take a look at it, assuming you don't do your own oil change that is.