750I sounds like a diesel engine at idle

My 2007 750I with 94K miles (still under CPO warranty) sounds like a diesel engine when it's idling. It's really noticeable when you are sitting in the drive through lane or standing outside in front of the car. The dealer has replaced the water pump, and most every pulley and accessory on the front of the engine and the noise is still there. I didn't think the late model V-8's had vanos or timing chain problems but now I'm not so sure. Anyone have any ideas, and do you think this is something that they will fix under warranty?

Alternator is a POS and should be checked.

Yeah these alternators are known to sound like motors losing their bottom ends.. Also heard the AC compressor can sound the same and vacuum pump can sound like top end ticking..

Originally Posted by cmpcpro

Yeah these alternators are known to sound like motors losing their bottom ends.. Also heard the AC compressor can sound the same and vacuum pump can sound like top end ticking..

Yep, my alt started ticking, really it sounded like a rod hitting the top of the head......scares me every time I start the car and hear a new noise. I now find myself with the air off and I sit there for a good 5 min just to listen to the engine. Lol.

Good luck.

Do you think this is something that the CPO warranty will cover if it's just click clacking noisily but working fine otherwise?

Originally Posted by Ltmax

Do you think this is something that the CPO warranty will cover if it's just click clacking noisily but working fine otherwise?

Depends on the dealer, they already know there is a problem, I would have left the car there untill it was fixed correctly. You paid for the CPO.

That's what I thought, it's a shame as it's been in the shop half a dozen times over the past 3 months getting leak after leak fixed including valve cover gaskets, alternator seal, cooling system, timing cover gaskets and a bunch more (nearly $4k in warranty work). Pretty sad for only 94k miles.

Originally Posted by Ltmax

That's what I thought, it's a shame as it's been in the shop half a dozen times over the past 3 months getting leak after leak fixed including valve cover gaskets, alternator seal, cooling system, timing cover gaskets and a bunch more (nearly $4k in warranty work). Pretty sad for only 94k miles.

Don't think about it that way, it's just that these cars are expected to last and they need to be babied all the time. Most every owner knows what they have and won't expect less than the ultimate breaking machine.

I spent 6g out of pocket this last year.

Well maybe she's doing me a favor and getting most of the common failures out of the way during the last 4 months of my warranty period.....

Thank goodness I've got 30 years experience turning wrenches as it seems like it'll be put to good use on my 750 next year. God knows my 540I seems to enjoy some type of attention almost monthly, but at least most of the problems on that one aren't that hard to fix. Not sure the 7 series is going to be as easy to keep in tip top shape....

would you have an idea what it might be on my car or where i can turn to ask these questions. I recently put on new rims to my 745li 22" and now when i hit bout 45-50 mph my steering wheels jerks a little and it seems to be coming from the front right driver wheel? any clues? Preciate you.

Well for one you are in someone elses completely unrelated posting.. If this was a post related to your problem and was old and abandoned it would another story.. anyway you either have a bad tire bent wheel unbalanced unit or a non hub centric setup

Originally Posted by cmpcpro

Well for one you are in someone elses completely unrelated posting.. If this was a post related to your problem and was old and abandoned it would another story.. anyway you either have a bad tire bent wheel unbalanced unit or a non hub centric setup

+1 He sounds desperate hehe

He's already created a post and got several responses...I don't get it. If he does a search there's a ton of threads regarding that issue, I had that same issue again things to check were already suggested.

Well after three trips to the dealer to fix the obnoxious diesel engine noise coming from the front of the engine and always getting the "could not duplicate" no action taken response, I took the serpentine belts off today and spun all the accessories on the front of the engine and just like several of you called it, the alternator bearings are bad.

I'm pretty glad that I did it to, because while I was troubleshooting the noise I found a pretty good oil leak on the vacuum pump, and a leak on the power steering rack that need to be fixed as well.

Looks like my last 3 weeks of CPO warranty will be very helpful.

Thanks for the tips.

Awesome.!

Dealer swapped out the noisy alternator, leaking vacuum pump, and found/fixed transmission mechatronic seal leak today. Runs nice and quiet once again (finally).