creaking noise in front suspension when a/c has been on for a long time

[Drifter33]

This is my first post, but I've been reading for a couple of years. So a big thank you to everyone for the information I have gained here.

So i have a strange situation. In my 2001 740il with about 90k miles, if I run the a/c on high for a long time I get a squeaking/creaking in the front suspension. It stops when the car stops and increases as the speed increases rolling away from a stop. So I think it is in a wheel bearing or something. I looked under
the hood thinking I would see something all frozen up, but couldn't see anything. I think the sound is on the front right side.

I googled this problem a bunch and couldn't find anything. Thanks for any help you can offer.

[racer2086]

Very hard to diagnose with what you describe. Does it change with the car speed or the engine RPM? When the A/C systems are low on refrigerant, the compressors tend to whine or moan. This is most audible at idle or low rpm. This is why I asked my question.

[Drifter33]

yes, the sound corresponds to speed. slower creaking when going slower and faster when moving faster. So I don't think it is really the a/c unit compressor or belts. just very strange.

[racer2086]

It may be that running the A/C on high for a while gives time for some heat soak. In which case it could be a control arm, center link, or bearing. You may need to have someone walk alongside the car while you roll slowly to see if the noise can be localized.

[tomquic]

Hi .. my money is on the centre link in the steering. This is a common problem with a 'creaking' after running for a while .. esp as the E38 is no longer a 'spring chicken'. We've had lots of similar issues in the Uk on the E38 ... have a look on www.the7seriesregister.co.uk and also Timms excellent website with a host of fixes for range of things ... http://meeknet.co.uk/E38/Index.htm Good luck .

ps - if you do end up having to replace the centrelink , its also worth doing the idler arms at the same time ..

[ebida3]

You sure it's not the AC belt? Spray wd-40 on it. See if it changes pitch or stops completely.

Check engine light (CEL) means 'Cost Estimate Large'

[ebida3]

You sure it's not the AC belt? Spray wd-40 on it. See if it changes pitch or stops completely.
It may be the clutch on the AC compressor going bad. Shut the AC once it starts. If it goes away you have a clutch or belt issue.
The belt turns all the time. Once you turn on the AC the compressor loads the belt. If the belt is marginal it will howl. The compressor on the other hand just turns while the AC switch is on.

Check engine light (CEL) means 'Cost Estimate Large'

Check engine light (CEL) means 'Cost Estimate Large'

[Drifter33]

Hi .. my money is on the centre link in the steering. This is a common problem with a 'creaking' after running for a while .. esp as the E38 is no longer a 'spring chicken'. We've had lots of similar issues in the Uk on the E38 ... have a look on www.the7seriesregister.co.uk and also Timms excellent website with a host of fixes for range of things ... http://meeknet.co.uk/E38/Index.htm Good luck .

ps - if you do end up having to replace the centrelink , its also worth doing the idler arms at the same time ..

Thanks to all for the info. I'm also just beginning to develop the dreaded shimmy at 50mph, so all of these suggestions make some sense. I hadn't considered that everything could be heating up. I rarely drive the car in the winter so any long drives are in the summer with the air on. I've had the car since 2003 and have really enjoyed it.

[gaspump]

My car has the same creaking sound after driving a bit. Its the center link. Changing it this week. Also my mechanic says it shoud end the 50mph shimmy so common on these cars.

[ebida3]

gaspump, you have this creaking only with the AC on?

Check engine light (CEL) means 'Cost Estimate Large'

[gaspump]

No a/c on, it creaks all the time. Strange that your's does it with the a/c. But it sure sounds like we have the same problem. I'll ask my man tomorrow when I'm there. Cheers

[ebida3]

AC clutch or belt.

Check engine light (CEL) means 'Cost Estimate Large'

[chrisn7]

Hi .. my money is on the centre link in the steering. This is a common problem with a 'creaking' after running for a while .. esp as the E38 is no longer a 'spring chicken'. We've had lots of similar issues in the Uk on the E38 ... have a look on www.the7seriesregister.co.uk and also Timms excellent website with a host of fixes for range of things ... http://meeknet.co.uk/E38/Index.htm Good luck .

ps - if you do end up having to replace the centrelink , its also worth doing the idler arms at the same time ..

Exactly as Tom says - had this, replaced centre link, problem solved. Apparently its due to the grease in the ball joints drying out from engine heat, but manifests itself either as the car warms up or ambient temp is high

[Drifter33]

Exactly as Tom says - had this, replaced centre link, problem solved. Apparently its due to the grease in the ball joints drying out from engine heat, but manifests itself either as the car warms up or ambient temp is high

Thanks to everyone for the help. The heat related issue with the center link makes perfect sense. I only drive this car in the summer and where I live it is hot in the summer so the A/C is on so I mistakenly thought it was a/c related. Got it. Thanks again!

[ebida3]

So when you drive and it's hot and you turn off the AC the noise continues, correct?

Check engine light (CEL) means 'Cost Estimate Large'

[Drifter33]

So when you drive and it's hot and you turn off the AC the noise continues, correct?

Check engine light (CEL) means 'Cost Estimate Large'

yes, it continues until the car sits overnight. thanks for the help.

[ebida3]

Not actually related

Check engine light (CEL) means 'Cost Estimate Large'

[ebida3]

Air conditioning related

Check engine light (CEL) means 'Cost Estimate Large'

[ebida3]

Not AC related

Check engine light (CEL) means 'Cost Estimate Large'

[ebida3]

Sorry darn spell check.

Check engine light (CEL) means 'Cost Estimate Large'