Rattle / tapping / clicking at 1500-2000 rpm

[andy m]

Hello all.

I have a 96 850 T5 with 157000 on the clock.

I am currently getting rattle / tapping / clicking at 1500 - 2000 rpm. Once it hits 2000 rpm it goes.

It is more noticable under load than reving the engine on the spot.

Engine temp makes no difference.

Any ideas would be appreciated.

Thanks in advance.

Andy.

[andy m]

Hello,

Have been listening to the noise today. I would best describe it as a ticking. Seems strange it only occurs between 1500 and 2000 rpm.

It is louder when you put your boot down compared to gentle acceleration.

Cant hear it with the window open but only when the window closed as if noise is coming from behind the engine.

Could it be a leak in the exaust manifold??

Any ideas please .

Cheers,

Andy.

[deathrider311271]

could be your cat

[andy m]

How , why, when ................. Sounds expensive.?

Cheers.

Andy.

[ozmorgan]

I don't know about the cat, it may well cause clicking. However to me it sounds dead on like a bit of stretch/lack of tension in the cambelt or potentially a hydraulic tappet has failed.

I've had the same problem over the last few weeks and am in the process of finding out whether the above issues are to blame. Certainly, several more experience mechanics than me have all agreed it sounds like tappet trouble. Key symptom, more noticable under load then idling - if it was the cat it would probably occur regardless. Under load there is more torque going through the camshafts and so it gets louder.

I'll keep you posted as to whether those are the culprits on mine.

N.B, there are additives you can stick in the oil to flush out anything blocking up a tappet. Speak to any experienced local indy for the best products to use. Personally, I'd replace all the tappets and be good for another 150,000 miles.

[andy m]

Hello all,

Took the car to my local Volvo specialist. They had a quick look and noticed that the bush on the top engine mount is split. They suspect that when the engine is under a lot or torque at low revs it is moving too much causing the noise from somewhere.

Does this sound plausable or migh I be looking at something else?

Have got it booked in, will let you know of the outcome.

Cheers.

[ShadeTek]

What is probably happening is at certain revs you hit a resonant frequency of the engine, causing it to vibrate back and forward enough to have metal hitting metal at the bush.

[andy m]

Hello all,

Car went in to the local Volvo specialists. They changed the split bush on the top engine mount and the noise has gone.

Just as they thought.

Happy again.

Cheers,

Andy.