I am new to this site and so far have not found a thread that matches my problem, so I apologise now if this is repeating something already out there.
I have a 2000 (X reg) S80, 2.4 automatic. After about 8 - 10 miles it develops a whine from the engine that is more pronounced and high pitched at idle or very low speeds. There is no change in pitch and appears to disappear at speed. (Maybe just me being as little hard of hearing). It also appears to cause the engine to fluctuate wildly at idle between 500 and 2500 rpm. The engine emmission light is also now on. It was in the repair shop just a few days ago and the mechanic suggested it could be excessive crankcase pressure. There are no messages on the trip computer. Any ideas about cleaning out hoses etc?????
I do have a recording of the noise but not sure how to post it!
Thanks for any help
Showman6677

 

Hi Showmann and welcome to the forum.

The first thing I would check is the last time the timing belt and rollers there were replaced. It may be causing the noise if a roller is about to fail and toss the belt.

An irratic idle can be caused by a massive vacuum leak or a MAF problem. Are there any codes?

 

RSPI, thanks for the welcome.
There are no codes, and as a matter of interest, with the weather being around minus 4c last week the noise did not develop.
I have only had this car for a few weeks, but as far as I can tell the belt was changed about 5 - 7000 miles ago.
The erratic idle only seems to occur at the same time as the noise, otherwise it runs and drives smoothly.
Regards

 

Perhaps power steering fluid is low.

 

mine did the same thing......it is the throttle body ! noticable whining at idle..cannot hear it when driving..... not sure why or how?..mine does it after engine is warmed up...so far has not affected performance. just my 2 cents

 

Thanks for that mrybar.
I did notice that removing the oil filler cap when the noise develops, although causing the idle to get very lumpy because of the sealed system, the noise disappears, suggesting a definate breather problem.
if I get a chance next week, I think I will strip out the top end and clean out all the breathers.
Regards

 

I had a XC70 that had excessive crankcase pressure due to a blocked PCV oil trap. It built so much pressure that it actually blew out the main seals and the camshaft seal as well as pushing oil in to the turbo. I'm not sure if the 2.4's have the same trap, but if they do, you will need to change that and the lines going to it. It sits low on the front of the block under the intake manifold. It's just a plastic box with some inlets on the side and inlets that go in to the block. If this gets impacted with goop and sludge, it will cause your crankcase to build pressure fast. You need to fix this before you take out your seals. As I recall, the parts weren't all that expensive, even from the dealer. You will want to pull the intake manifold to make it easier.

 

bcpape, thank you.

That does sound more like it.

I am presently in the process of packing, as we are moving house in a few weeks time.

Looks like my first job is to get this sorted before it causes any further damage.

I will keep you posted on how it turns out.

Thanks again

Showman6677

 

got smoke coming out of your dipstick?

sounds to me the odd idle is being caused by a bad check valve, but it wouldn't explain the noise. A plugged PCV has a certain odor to it and very easy to spot in most cases. a throttle body problem would throw a code, but not necessarily throw the light.