engine/belt noise?


norteno
11-27-2011, 08:32 PM
I have a 98 century limited. It has 165,000 miles on it. It sat in the garage for about a year and it starts and runs, idles, accelerates just fine but now has a fairly loud mid-pitched metallic scraping or scratching sound when idling and accelerating. It is NOT a high pitched squeeling or sreeching and not a low-pitched grind or growl either. It did not have this sound before. The belt does not have any cracks or tears and seems fine. I noticed some rust on the pully surfaces on power steering pump, and belt tensioner. It is minimal on PS pump pully but substantial rust on belt tensioner pully. Could this cause a noise like this? I loosened belt and spun all pullies and they all seemed smooth and not wobbly or binding. I thought maybe tensioner or maybe water pump but I ran the car for a good 45 minutes and did not notice any leaks or strange smells or movements. Heat comes out good, alternator charges, steering does not whine or stick. I cannot pinpoint exactly where sound comes from but definitely around where belt goes through these components. I sprayed some belt conditioner on it but had no effect at all. Any ideas anyone?? How do you check these things?:banghead::confused:

Tech II
11-27-2011, 11:00 PM
First, turn the A/C on, when the clutch engages, see if the noise goes away/changes.....if it's not the clutch, remove the belt and rev the engine and see if the noise goes away...

brcidd
11-28-2011, 10:25 AM
Sounds just like a/c compressor clutch scrapping sound from here...As stated- see if noise quits when a/c is on and clutch is spinning....if so then do a search for "V5 clutch drag" there is probably corrosion behind drive plate, not allowing proper air gap- look for metallic particles on clutch face to confirm..clutch can be adjusted to solve issue.

norteno
11-29-2011, 09:31 AM
thanks for the quick response guys. I won't be able to work on vehicle until weekend but definitely will do what you guys suggested. Come to think of it, I did notice some metallic particles around AC compressor and some are magnetized to it's pully. I thought they were maybe from shavings from when i just drilled out ball joint rivets but then again, I noticed the sound before I even did the ball joint work. Thanks again and I'll update this weekend. I really like diagnosing car problems instead of just throwing parts, and money, into it and this site is great!! If it is in fact the AC compressor, could I just install a shorter belt and bypass compressor until I get it replaced or adjusted next spring?

brcidd
11-29-2011, 09:58 AM
Here is what is probably going on.....

V5 clutch drag (http://www.autoacforum.com/messageview.cfm?catid=20&threadid=18819)

norteno
12-08-2011, 05:33 AM
thanks. that sounds like what it is. I haven't tried anything yet but been doing a lot of reading about v5 adjustment. What I understand, I have to loan the proper tools, loosen nut or bolt that holds clutch plate on, then use the clutch puller to move clutch out away from pully to proper air gap (.020) using feeler gauge. Sounds pretty straight forward and I think I can do it from inside engine compartment and wheel well. My question is, the instructions/diagrams I found mention some "clutch hub spacers" that allow for proper air gap. Do these need to be added or removed to maintain proper air gap or do I just re-tighten the clutch back on once I have pulled it away from pully the proper gap and avoid having to pull clutch completely off to access these spacers behind it? It doesn't say in the instructions I found. Thanks again!!

brcidd
12-08-2011, 09:09 AM
The V-5 is different from most- it does NOT have clutch shims or spacers...you can pull the clutch out- and not worry- it is a press fit- designed that way- it will stay in place forever after you move it out....the nut on the shaft does NOT hold the clutch down- it is there to make sure the key stays in- (it bottoms out on end of shaft, not clutch hub) later models quit using the nut to save money.

As a matter of fact, you need not even loosen the nut to move that clutch hub out .020". (1/4 to 1/2 turn of puller)

I've done several this way- just make sure you use the clutch remover tool properly and only thread into clutch..NOT to shaft to remove....this is the most common mistake- trying to thread into both at once. The only time you thread onto the shaft to install clutch.

You make want to clean the corrosion off clutch hub threads with a pick tool first, and add some PB blaster on threads.

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