As others may know I recently replaced all the accessory belts on the 928. I was hoping that the belt change would help some but it didn't.

Anyhow, do all 928's have a lot of noise? Is it normal? I am comparing it to my VW (daily) and my memory of the Ford. I know I should be comparing it to other 928's but I haven't thought about it at the GTG's and for that matter I didn't have things squared away at the last one. I have had a couple of others listen but I am not sure they agreed that it was loud.

Maybe it is just dry bearings on the accessories as they are getting up there in age. I know that Jason bought a new alternator cause he felt he was having charging problems and it was whining but I wouldn't say whine as much as whuuring.

Thanks, I know another crazy question from yours truly.

Michael

 

You could have tried putting one belt on at a time until you identified the noisy culprit. Certainly the AC pulley bearing is known to fail. I've replaced a couple on other peoples' cars. The rest of the pulleys run directly off shafts. The component itself (power steering pump, air pump, alternator) has the bearings. Any one of these are known to get noisy too. You could try the hose to ear trick to try to localize the noise, although loose hoses and rotating belts don't mix well together, Anyway, the belt themselves should not be noisy. Most likely one of the components or the AC pulley bearing is on the way out. Now that you have all the belts on, try removing them one at a time.

 

Bill,

IMO it was noisy, not ear wrenching, but audible sitting at an intersection w/windows down, before the AC pulley although it has added to the chorus now since installed.

As to pulling them I may as I do need to get back in there to re-tension them in a few miles. Not in a big hurry as I don't put a lot of miles on it.

Michael

 

Try Bill's suggestion... Also, belts loosen up a bit after they've been run in, and may need to be re-tensioned.

 

I have had two 928's one 84 model and this 89s4. The culprit on my 89 is the air pump. For ****es and giggles Dusted the intake of the air pump with graphite then with wd-40 and it made the car quiet for about 4 days then the noise came back......Cant wait for an x-pipe and new cats to rid my self of the freakin air pump

 

I went ahead and recorded what I am listening to. This is from infront of the car w/the hood open.

The file is 850k so it may take a few for the dial-up users. Right click and choose "save" or "save as":

http://members.rennlist.com/michaela...Recording1.wav

I think that it is more noticeable in the recording after I give it a bit of throttle and then let it return to idle.

Michael

 

As Loaded found, the air pump is famous for getting noisy. Mine must have injested something other than air a while back and it started making noise. However, it went away and the pump still happily pumps.

Also, be sure it is the accessories and not something under the timing belt covers, if you know what I mean. I'll listen to the clip, but it's more important where it's coming from.

 

Sounds like a noisy bearing to me. Just be sure it's not the water pump or a tensioner pulley bearing!

 

Sounds a little like my 90GT.
I cut the airpump belt since an X is going in.
Silenced things a bit, but still has a noice which is not belt related.
(i think)
Bill, can you replace the AC pulley bearing with the compressor and lines still hooked up in the car?
My waterpump and all rollers have just been replaced so they should not be the culprit.

/Peter

 

Thanks guys, before I bought it the TB/WP were replaced but I will have to read back and figure out if the tensioners and rollers were replaced as well. I doubt that I even have 1500 miles on the car since those were replaced but it has been about 6months. I know, adjustment time.

Michael

 

Peter:

Yes, the AC bearing can be done with the compressor mounted. Loosen the bolt on the pulley and remove. Pay attention to shim washer position. Pound the old bearing out of the pulley - it is usually peened in place, so grind off the peens before pounding. Pound the new one in. You could freeze the bearing to make it easier, but using a large socket to drive the bearing in (or a vice to squeeze it in) works fine on its own. Reassemble. I can get you the bearing numbers later.

 

Michael,
Use a mechanic's stethescope, a LARGE screwdriver with the handle pressed to your ear to localize the noise while the car is running. It needs to be long enough to reach the pulleys, water pump and oil pump areas without putting you in danger of the fans.

 

I guess at this point the message is clear that your engine is making too much noise. No one came right out with it, but having listened to your recording I can tell you that something is not right. My '79 is nowhere near that loud.

 

Okie doke. Thanks guys, PM'd the RL'r that did the TB and WP, hopefully he will reply and let me know if he did the rollers and tensioners when he was in there.

Michael

 

Michael,
Whether or not he did the rollers you should not make any assumptions. It's possible that new bearings could be improperly installed or could fail prematurely. If I were you I'd assume the tensioner bearings, water pump and oil pump bearings are bad until I'd satisfied myself otherwise. Any other cause is non critical.