Ghost in the engine?

[MikeyH]

Firstly, I absolutely love my Z4 so much that the wife keeps telling me to shut up going on about it or she’s leaving home . However I know that Halloween :evil: is just around the corner but I have noticed a strange ghostly whhooooooo sound when I accelerate through the gears or sit still and gently rev the engine. I’ve read quite a few threads with talk of whining, has anyone found out what it is or is it a feature of the 2.2i engine?

 

[PDJ]

few threads with talk of whining

Leave your wife at home

 

[MikeyH]

few threads with talk of whining

Leave your wife at home

nice one

 

[buzyg]

few threads with talk of whining

Leave your wife at home

Or at least let her sit in the car, not sat in the engine bay. You could damage something that is clearly precious to you. :wink:

 

[enuff_zed]

Have you checked the small concertina'd pipe on the inlet to the throttle body.
I had exactly the same kind of noise on the 3.0i I just brought home and found a hole in it.

 

[MikeyH]

Have you checked the small concertina'd pipe on the inlet to the throttle body.
I had exactly the same kind of noise on the 3.0i I just brought home and found a hole in it.

Thank you I will have a look today

 

[MikeyH]

I still have this noise and checked the concertina pipe and it was new. With the roof down it’s not as noticeable so have forgotten about it but yesterday I moved the car out of the driveway with roof up to unload luggage from my wife’s car and it was very noticeable. Quite loud. Could this be a pulley or drive belt, the water pump was changed by a previous owner. Has anyone who has this noise found out what it is. Would a K and N air filter be the problem? Thanks in advance.

 

[enuff_zed]

Can you get your wife to rev the engine while you have your head under the bonnet. Be helpful if you knew what area the noise was coming from.

 

[patriot66]

Some oil filter elements can make a peculiar loud noise. I did an oil change a few years back and used a K&N oil filter that made a right racket. Never had an issue since with Mann or Mahle filters

 

[MikeyH]

Thank you enuff_zed and patriot66 for your replies, got the wife to rev the engine, although she got a bit carried away with it and had to ask her to calm down a bit, and the sound seems to be coming from the alternator area. The previous owner before the one that sold me the car had replaced the water pump but not the alternator. Could it be this do you think? This is the m54 2.2 engine by the way.

 

[enuff_zed]

Possibly the alternator, but there are also a couple of idler and tension pulleys in there which could be the issue, and hopefully a lot cheaper!
Can try carefully aiming a squirt of WD40 at the top idler pulley and see if it quietens down. Try to avoid covering the belt though.

 

[MikeyH]

Thank you enuff_zed, I give it a go tomorrow.

 

[BumpyZ4]

Some oil filter elements can make a peculiar loud noise. I did an oil change a few years back and used a K&N oil filter that made a right racket. Never had an issue since with Mann or Mahle filters

Agreed. Check the oil filter for collapsed pleats. They will make a hell of a whining noise.

 

[MikeyH]

Okay, I have carefully squirted some wd40 around the pulley at the top where the sound seems to come from but no difference. It's more of a whoooing noise like wind blowing through an open door or window rather than a whining noise.

 

[patriot66]

Get a decent oil filter and change it. Dead easy. If its stops whoooing then happy days. If not, are you able to jack up the front/drive it on ramps ? You can then remove the undertray and get much better access to the belts and all pulleys etc. You can pop the dust covers off the tensioners/idlers and locally spray some WD40/GT85 etc in each bearing and see if it quietens any. Alternatively, remove both belts and start the engine for a minute. If silent then it's definitely something on the main v-belt. You can then examine each bearing including waterpump and alternator in turn for roughness, play and wear etc. This is my M54 2.5i but your 2.2i will be the same

A = Air Con belt tensioner
B = Waterpump pulley
C = Alternator pulley
D = Upper idler pulley
E = Lower idler pulley
F = Tensioner pulley

 

[MikeyH]

Thank you patriot66, I’m afraid that is a beyond my skill. But from your photo it definitely looks like one or more of those.

 

[Z4Mariner]

MikeyH -

Patriot66 mentions a key thing for your testing: The WD40/GT85 might not get past the pulley dust covers very easily, so remove if possible.

Another way to test is to remove the belt and spin idler pulley (if present) and the tensioner pulley by hand - if they spin freely, there's not enough grease, and if they wobble the bearing is finished. A common issue for many older BMW's - the plastic pulleys are not always replaced when the belt is changed out .

 

[paddy wright]

Just to be sure you checked the right pipe for the split you did check the one circled below, it comes off the intake boot in to the engine from the air box, known to split?

 

[MikeyH]

Thank you z4 mariner, it’s looking more like a job for the garage. PaddyWright, that’s not the one I’ve been looking at, it was a bigger one. I will have a look later. Many thanks for all your help guys

 

[paddy wright]

Check this tread to show you where the split will be and if so how to swop over for a new one https://z4-forum.com/forum/viewtopic.php?f=3&t=5592&p=1037799#p1037799