240gl Strange noises

[sbward1975]

Hi Guys,

Just got myself a lovely 1990 240gl with 108k and full history,i cant fault it and im really happy with it....but its suffers with 2 strange noises.the first is in the cabin and sounds like a fan sound which gradually gets louder??? the second is underneath the car a squealing noise that happens occasionally when accelerating??? Your help would be greatly appreciated as i want to get this car in pristine condition.....my 5 year old daughter loves it,and has told her friends at school that ive bought a monster truck!!! i feel they may be disapointed when they see it

Many thanks Stuart

[jmz]

maybe the fan sound is the viscous fan? ...or just the engine, I think it has a very unique sound similar to some big 4x4s.

the squeel ...clutch squeel?

[John Sweeney]

Or a worn fan belt could be causing the squealing if it sounds like it might be coming from the front of the car?

[Clifford Pope]

Try and determine the precise circumstances when the noises happen:

Moving/ stationary?
In gear or coasting?
Related to engine speed or road speed?
Clutch in or out, when engaging?
When reving?
Affected by brakes?
Power on or on overrun?
Fan belts OK, not slipping?
Alternator?

240 noises are a devil to pin down, and mine have suffered from most of them over the years. It's often a matter of painstaking elimination of possibilities.

[sbward1975]

Hi Guys

Thanks for the replies,

On further investigation,the squealing noise happens straight after/during some gear changes? the interior noise seems to be coming from behind the centre console and gets gradually louder as i drive....heater blower maybe???

Thanks in advance Stuart

[Clifford Pope]

If it is the heater blower then you can test it when stationary, without the complication of engine/road noises. They are famous for squeaking and squarking, but fixing it is reputed to be the most difficult job on the car.

I find I can sometimes persuade it to be quiet by turning up the speed, then easing down a setting, or by speeding it up slowly. Sometimes it develops over time, and twiddling the speed knob will silence it.


Does the other squealing noise coincide with operating the clutch? If it does it just as you let the clutch bite, it might be the release bearing.
This can be lubricated by pulling back the rubber boot in the flywheel housing where the clutch operating lever projects. Try a well-aimed squirt of aerosol spray lubricant.

[brodgar]

check the engine mountings.

when one has come loose/broke up ( usually passenger side)

than you get disallignment in the whole drive line.

when you change gears-up=== you aplly extra torque .

======================

trolley jack under the engine- one side-- if you can lift the engine without that the chassis moves with it-- you found the problem

[MTerry]

I've also heard that the centre bearing in the driveshaft will squeal when it get worn. That would make sense right after a gear change when torque is reapplied to the driveshaft.

[Clifford Pope]

I agree about the prop centre support bearing making a noise. It can be confused with much more serious axle noise. But I think its distinguishing feature is that it is constant at a given speed. It doesn't transmit torque, just supports a spinning shaft.

As I said, there are dozens of possibilities, and I for one have frequently been fooled into thinking a noise had to be caused by the same thing as caused the last one that sounded the same.
If yours does it as you engage the clutch, try the effect of easing the clutch pedal a bit - does it alter the noise, or is it to do with the other circumstances associated with that, like that particular speed, or gear, or easing off the throttle, or engaging it?
Can you make it do the noise if you ride the clutch?

[mrkawasaki]

Re. squealing (mild and distant sounding - from the passenger footwell area)

Mine makes a similar noise (randomly) when accelerating mildly if I slowly release the clutch pedal in 1st or 2nd. Other times/ways - no noise. Sounds like a 'dry'/please grease me sort of a squeak, not a metal-on-metal noise...!

Other noises:

Constant low pitched electronic whine from the back of the car (saloon) and, usually 3 minutes after driving off, a low plastic 'tick' - like something has warmed up and expanded, from the fuse box area.

Such fun!