DW42
My 1990 240 sedan has what I think is a little belt noise on the AC compressor/PAS side. I thought it would disappear with a belt change and new accessory bushings, but it's still there. While it sounds like a slightly slipping belt, the pattern of when it makes the noise is not like any loose or old belt problem that I know -- it starts up in the morning without the noise, then when it's been running more than 5 minutes the noise begins. This has been an occasional winter problem for 5 years -- especially after driving on the M1 for a few exits, but now it's both louder and happens more often. If I drive it a lot in a day it will eventually go away, but is back the next day. I'm thinking it may be a bad bushing in the AC compressor or PS pump pulley, and am planning to drive it without the PS belt for a little bit to see if that cures it. But I may be missing something obvious, so any ideas are very welcome...
Also -- am I nuts to try driving a 240 even for a short while without the power steering?
familyman
Well, it will be heavy without the belt. So depends on your arms, lol. I would over-inflate the tyres to reduce friction (say 45psi), and park the car out on the road before removing the belt - and facing back already TOWARDS your home/driveway without too many turns, just in case.
But an easier way might be to carry a squirter bottle with some water. i.e. You're indicating it does it after running a while - which is when the belt has had time to warm up. So if it IS just the belt, get out when it makes the noise, start spraying cold water around. If it changes/stops you know it's the belt itself. If it doesn't change then maybe think about belt removal. But I'd go another step before that and squirt some CRC "electrolube" into bearing areas - or maybe silicon spray before getting tools out and removing belts. (Don't get silicon spray on the belt obviously. It could start slipping.)
DW42
Yesterday I tried spraying CRC belt grip on the belts. Even with the little straw it wasn't a very tidy process. When I fired up the engine the noise was much worse for a bit, then it went back to how it was. But I'll try hitting the bearing areas with silicon spray and see what happens.
carnut222
How's the belt alignment - could be mounting bushings. Also sometimes the power steering pumps are noisy...
jamesinc
Bushings or other alignment issue probably. 240 will drive fine without power steering, you'll mostly inly notice it when reverse parking. I don't think there's much of a need to over inflate the tyres
nickm
balancer slipping?
Common on b230 is the harmonic balancer outter moving on the inner.
familyman
Over-inflating tyres might be overkill. I had a 240 heading for scrap that was getting more difficult to start and move around the yard. It's tyres were down a bit. Man alive, what a struggle it was to turn the wheel so it could be dragged onto a car trailer straight. Maybe it was the combination of low tyres and being parked on dirt. Only other experience without PS was years ago with an XD falcon on a farm. Not sure what the fault was, but no PS. It was the most effort I've ever had to put in to turn a car.
240
I'd be interested to see if you get this sorted.
My 240 has a noisy AC belt as well, although unlike yours it is always noisy, not intermittent.
It sounds like a sort of loud papery sound.
If I spray silicon spray on the belt, the noise goes away for about 15 seconds and then comes back.
The belt was very slightly loose, I adjusted it and it's now a tiny bit better but not much.
I was going to just replace the belt but after reading your post I'm not so sure it''ll fix it.
Thoughts anyone?
DW42
Thanks for the replies. I'll certainly have a look at the harmonic balancer. One thing that I have neglected is the condition of the pulleys. The surfaces that contact the belt are quite shiny on the AC pulley, and the PS pump pulley just looks dirty. I'll clean and very lightly sand these.
Vee_Que
Worn pulleys will cause this. Seen it many times on trucks in particular.
Ex850R
As Alex says, pulleys wear out and these cars are old...
DW42
I just removed the PS belt and the noise was still the same. Next I removed the AC belt and the noise was gone. The pulleys both spin freely and without noise, but the AC pulley is shiny -- suspicious? I'm leaning towards either there being a problem with the alignment of the AC pulley, or the harmonic balancer. Not sure about the harmonic balancer theory though, as my understanding is that if it was slipping the timing would now be off. The engine runs fine. I may give up and take it to the experts (I'm lucky to live relatively close to Stevensons Automotive in Nerang).
nickm
No... your timing does not move if the balancer is slipping.
It is only if you have a timing light on it will show incorrect. Or trying to install a slipping balancer.
It is a very common problem.
Take a marker and mark across both sections and run the car with belts on.
DW42
Will do this at the weekend.
DW42
I marked across the sections and the marks stay lined up. This leaves the AC pulley as the likely culprit. Strange since it spins so freely without the belt attached. I cleaned and sanded to slightly roughen the surfaces on the AC pulley, but it made no difference to the noise. I think what I'll do is get an AC compressor from the wreckers and get it rebuilt, then swap it over. I don't think there's too much chance of finding a good compressor at the wreckers.
DW42
Update on the belt squeal saga: I bought a brand new Sanden AC compressor for 300 dollars and installed it today. No more squeal. It's booked in for a new dryer and a gas next Tuesday. The Sanden compressor is different from the original Diesel-Kiki, but fit fine.
The sedan has been out of use for a while: I can hear another noise now there's no squealing -- it's whining. I'll top up the diff and check the ATF.