What is this noise?

[Palmetto]

I picked my first Z3 up today. It's a 2.8 in Palmetto Green. I had to drive 100 miles home in this storm and took it easy. Half way back I stopped for fuel, and noticed a whining that increases/decreases with the engine speed. It definitely didn't make this sound on the test drive before I bought it, and also when I set off after picking it up. When I got home, I left it for an hour and then drove over to my friends, about three miles away. It didn't make the sound when I set off and it only started when I was near his house.

It sounds like a supercharger. I'm guessing it's something pulley or alternator related, although one suggestion may be that it needs a power steering fluid change. There's no noise coming from the steering when you turn the week.

What do you reckon?

Oh, and here's my car.

 

[spurs fan in a coupe]

No idea what the noise is, but car looks beautiful

 

[t-tony]

Most likely part of the auxiliary drive belt system. On my Z3 it was the belt tensioner bearings, new tensioner is about £65 ish. If it is that you ought to be looking at a cooling system refresh. What miles has the car done and is there any history of this type of repairs being done?

Tony.

ps. Unlikely to be power steering issue. You can check the fluid for level but it would only likely become noisy is fluid had leaked out.

 

[Palmetto]

What miles has the car done and is there any history of this type of repairs being done.

It's done 104,000. I'll have to check through the history. I'm convinced he said it had a new water pump and thermostat, but I may be getting mixed up with another I looked at.

 

[Chrisr1949]

Hi and a big welcome from Southport, yeah I had this and it was the belt tensioner. There's probably a pelican parts.com video on how to do it. They're a remarkably helpful site in the US for DIY repairs.

 

[Sean d]

Does it have AC, I had exactly the same on a 2.8 that I have just sold, turn the AC off and sound dissapears

 

[andyglym]

Looks great

 

[Palmetto]

I had this and it was the belt tensioner. There's probably a pelican parts.com video on how to do it.

Cheers Chris. I know Pelican Parts (we also have an E36) so I'll take a look.

Regarding the cooling system. It's had a new thermostat and various hoses in the last couple of years.

 

[Palmetto]

Does it have AC, I had exactly the same on a 2.8 that I have just sold, turn the AC off and sound dissapears

No AC.

 

[t-tony]

The AC would affect the belt tensioner noise by the loading it takes to drive the compressor. You would be advised by many on here to check also the plastic cooling fan for any signs of cracking at all as these are well known for shattering with ages and often taking out the radiator with them.

Tony.

 

[Palmetto]

Now, this may be where you all laugh at me. I have taken a video of the noise. When I first heard it, it was a lot louder than this, and I thought it was a wheel bearing whining or something. It's never been as loud since. It does seem quite quiet on the video. In the cabin it is louder.

https://www.youtube.com/embed/pkIYKg6rWSc

Turn it up. It kicks in at 2500 rpm. You're probably all going to say, that's the normal sound of an M52B28TU, and if that's the case, I've probably been driving four pots for too long.

 

[Scooblitz]

Possible viscous fan? Sounds similar to mine.

 

[Nodzed]

I'd check the viscous coupling first.

 

[Palmetto]

I'd check the viscous coupling first.

Yep! That's it. It's in the garage today for a service and water pump. He reckons it's the viscous coupling too.