Engine: B5244: Vibration

[kymg]

G'day all,

I have had a vibration in my engine that occurs when the engine runs at at about 1000 - 1200 RPM. The engines sounds find when the car is started cold in the morning but as it warms up the vibration occurs.

I had thought it was the serpentine belt tensioner and so I replaced that (noting that it is not as easy as it seems in the movies). I started the car from cold again and the vibration reappeared.

I have tried to locate the vibration using my favourite screwdriver held against the engine and my ear to no avail. So I am at a loss.

Any help appreciated.

Cheers

Kym

[Georgeandkira]

A higher speed "buzz" or a shake?
Engine mounts?

[kymg]

Hi,

The vibration occurs when the car is warming up from cold at idle. As the rev drop from 1400 - 1500 to idle speed it vibrates at about 1000 - 1200. Usually around 1100. If I rev the car the vibration goes away.

It is not a constant vibration but rather one that has a frequency - every two to three seconds - much like an engine 'hunting' i.e. It is cyclical. The engine does hunt a bit also and does not sound smooth.

When I rolled the tensioner before it came off it felt rattly hence the removal although now it is off it doesn't feel quite as bad.

It has me flummoxed I must say because I do not like a noisy engine and it worries that something could go wrong.

I will scream to myself now. It is most frustrating.

Cheers

[Georgeandkira]

This is a "shot from the hip" (a cowboy shooting reference which pre-excuses me for missing).

Since the sound has a "hunting rhythm" to it I suggest addressing any maintenance operation which can initiate hunting like giving the ETM a clean if necessary.

Since it's not an intolerable effect you have time to see if adding Techron concentrate (or one which contains PEA) to your fuel will help. Add this stuff before a stint of local driving.

Which engine do you have? Neglected plugs? Turbocharged?--check seating and condition of air/vacuum handling hoses.

If you have spark plugs try removing them and doing a compression check. It's easy to do.

[kymg]

Thanks georgeandkira,

Spark plugs - genuine replaced about twelve months ago.

I am inclined to head towards the ETM option. The car does about 18,000km per year with approximately 75 - 80% town running. That may be contributing to the problem

Have read that ETMs are an issue. Now I will have to investigate the method of cleaning. I do not know what the concentrate that you speak of is. I will investigate that too. Who are the manufacturers of it. It may not be available in Australia.

Thanks again. Have a good one.


Kym

[mirelay]

Have you solved it? Mine S60, 2.4l non turbo does the same? After this short period of vibration, it settles, but a very light sound starts, which I thought is the timing belt tensioner.

[oragex]

Production year?

The throttle body butterfly valve may be dirty, or there may be a sensor issue somewhere. I'd also recommend keeping in the trunk a spare ignition coil and tools to replace it if it happens to fail while on the road.

[mirelay]

Mine is 2001, the throttle is repaired by Actronis with Sacer hardware (I bought the car like this and didn't know in the beginning). It also has strange rpm behaviour, but I will ask in another thread.

[ukdido]

Worth to check harmonic balancer -crankshaft pulley..

[petey]

Is the a/c clutch operation not cyclic? Turn the HVAC completely off and see then?