240 General: Rough and Noisy

[iluscombe]

Hi all,

Recently I have begun to notice more and more just how noisy my car seems to be. All the other volvos I've had (and notice in the street) seem to have that nice smooth metallic sound as it runs/goes along but mine just doesnt seem like that.

Mine seems to sound coarse and rough when accelerating but is reasonably quiet at idle. The car is an 88 240 GLT with 150k on it and an auto gearbox.
I know it might just be a case of a worn engine but I was wondering if anyone could suggest anything that I could check.

Look forward to hearing your replies.

Thanks

Ian

[Clifford Pope]

For a start, try and distinguish between fundamental engine mechanical noise, like valve gear, piston slap, bearing knock, etc, and noise from peripherals.

Things I'd look at are:

alternator brushes
water pump
creaky old fan belts
timing belt roller
steering pump or belt
excessive valve clerarance, or worn or corroded adjusting shims
leaking exhaust
old exhaust pipe corroded thin, or joints moving or not supported properly
air intake leaks
viscous fan coupling failing, causing constant fan noise
propshaft centre bearing noise
air gap at gearlever boot

Some of these can be eliminated by temporarily disconnecting belts, or squirting with WD40.

Is it related to engine speed, or road speed?

[iluscombe]

Thanks clifford I will do some investigation tomorrow as I have a day off. I have a feeling it will be combination of everything.

I have the exhaust manifold gaskets so will replace them so I can rule them out of the equation.

I look forward to getting the car sounding as good as they usually do.

Ian

[Clifford Pope]

Good luck, Ian.
You may with luck find it is nothing too serious, or just, as you say, a combination of several things.
I have often found that minor maladjustments can cause a disproportional loss of power, smoothness, or increase in noise. Also any irregularity in running, eg one cylinder with a less than perfect plug, seems to magnify any faults. So it would be worth checking that plugs, leads, coil, distributor, injectors, flame trap, throttle body, idle air valve, etc etc etc are all tip top.
I suppose too you ought to check the compressions. Even if all good, too much variation can cause roughness.
Finally, and it may be a psychological effect, a new timing belt and an oil change seem to make a car feel better.

[Checkpoint Charlie]

Hi Ian,
Squeaky belts is a problem often caused by worn rubber support bushings in the alternator. Some Volvos have them in the power steering pump but my 85 245 GLT definitely does not. After replacing the alternator rubber bushes which were definitely off centre after 100,000 miles and 18 years of use I found I needed to slacken off the bolts which held the power steering pump and use the slack in the bolt holes to align the pulley so that if one put a straight edge across the face of the pulley it would be in line with the crank pulley. Originally mine was at an angle so the belt was bearing more on one side of the pulley which was one of the causes of the squeaks from there.

I would second the comment about the fan clutch as the fan makes a lot of noise when it is clutched in so would sound rough pulling away.

When you say it sounds rough do you mean it sounds rough from inside the car or when you are standing there and it drives away form you?

Small exhaust blows/leaks at the silencer joints are a problem sometimes which add to the noise.
Regards,
Charlie

[xasm]

Originally Posted by Checkpoint Charlie

Hi Ian,
I would second the comment about the fan clutch as the fan makes a lot of noise when it is clutched in so would sound rough pulling away.

I think my 240 has the same issue. It sounds like a bus when I'm starting from rest. Usually occurs after I've been driving on the highway for a while, but lately it's been happening more and more. Often goes away after I've been in 3rd gear for a minute or two. I think I should check my fan as well, but I'm not quite sure how.

How is this issue diagnosed?

Cheers,
Tim