Help Me Diagnose Driveline Noise

Hey Fanatics,
I have been trying to diagnose a oscillating noise from my driveline. I have a 2001 325i Auto and the sound increases proportionally with increasing RPM's. (More RPM's, the faster the repetition of the noise) It happens in P,R,N,D so I doubt it has to do with the wheels or suspension components. For example, when I start the car up, in P, I can hear a ticking noise coming from under the passenger seat side of the car. It is not coming from the front of the engine for certain. In my opinion it could be anything from the rear of the engine all the way to the rear of the car. Transmission is fine. No slips, no gear failures that I know of, and I just got my transmission fluid changed the correct way, with the correct fluids from ZF and etc etc back in July.

What could this be? Hopefully the guibo.

well if its in park and the driveshaft isn't moving I don't see how it could be the guibo??

I guess it wouldn't be then. What could it be then?

Alex is right...driveshaft isn't moving in park.

...and not to argue with you, but it's very hard to figure out where a sound is coming from. If it's definitely not under the hood (you should listen with a stethoscope or hose), then the only other things I can think of is fuel pump. There's nothing else moving when you're in park.

Try filling up the car above 1/2 full and see if that quiets the noise down (if you happen to be low on fuel)...

Originally Posted by dmax

Alex is right...driveshaft isn't moving in park.

...and not to argue with you, but it's very hard to figure out where a sound is coming from. If it's definitely not under the hood (you should listen with a stethoscope or hose), then the only other things I can think of is fuel pump. There's nothing else moving when you're in park.

Try filling up the car above 1/2 full and see if that quiets the noise down (if you happen to be low on fuel)...

3/4 Fuel and 3/4 between lines on the dipstick with BMW 5W-30

Replaced Fuel Pump in August with Siemens VDO

Could be my exhaust leak that I have probably?

It could be an exhaust leak too. Why do you think you 'probably' have one though?

Heat shield possibly. Also check the exhaust bracket that mounts to the trans, sometimes it breaks and rattles against the exhaust

Thanks for all the thoughts guys. I'll check the heat shield. But yes, I have a visible crack on the resonator, causes the exhaust to be hoarse between 1-3 RPMs...saving up for a catback system

If the sound is RMP dependent, meaning if the sound increases in repetition as the RPMs increase then it has to do with engine and engine driven parts. You have to start diagnosing by the process of elimination. Take the bets off and start the car and listen to that same sound that you heard with the belts on. Obviously start the car when its cold so you have a good 10min of safe engine running time before it'll start overheating.

It could also be as simple as an exhaust leak or a loose heat shield.

Originally Posted by Blocked Out

If the sound is RMP dependent, meaning if the sound increases in repetition as the RPMs increase then it has to do with engine and engine driven parts. You have to start diagnosing by the process of elimination. Take the bets off and start the car and listen to that same sound that you heard with the belts on. Obviously start the car when its cold so you have a good 10min of safe engine running time before it'll start overheating.

It could also be as simple as an exhaust leak or a loose heat shield.

Thanks blocked. Always love hearing from you. I respect your always professional advice, and you are one of the only fanatics that I respect to the utmost.

But back to the topic, I have diagnosed it as a exhaust leak. I covered the crack up with some rags and the noise became muffled.

Originally Posted by Sweetness

Thanks blocked. Always love hearing from you. I respect your always professional advice, and you are one of the only fanatics that I respect to the utmost.
But back to the topic, I have diagnosed it as a exhaust leak. I covered the crack up with some rags and the noise became muffled.

someday this could be me

might be the exhaust heat shield that goes over the exhaust manifold. Mine is a bit loose and it starts to "tick" every once inawhile. All you need to do to confirm it is or is not that is to touch it with something to hold it steady.. if noise goes away, that's it. it is on the passenger side of the car too.

Or maybe a leaky exhaust/bolt/exhaust rubbing against one of the heat shields down there?

or could be valve lifter tick

Originally Posted by Sweetness

Thanks blocked. Always love hearing from you. I respect your always professional advice, and you are one of the only fanatics that I respect to the utmost.

But back to the topic, I have diagnosed it as a exhaust leak. I covered the crack up with some rags and the noise became muffled.

I was going to say that as you increase RPM's you're directly increasing the exhaust gasses coming out of the engine, so the two main areas that this points to are engine driven components, and exhaust.. glad you diagnosed it! upgrading exhaust can be expensive, but man, talk about rewarding!!!

Originally Posted by Alex323Ci

someday this could be me

No... you're already there

Originally Posted by ///mpr77

no... You're already there

+1!!!!

Alex is definitely on my list. (And not my block list--I took him off)

One day I'll place my hands underneath Alex's intake manifold and feel around to make sure everythings OK. I'll also touch other parts of the engine bay. If I see any dirt on my hands after an engine rub down, his name gets erased off the list. Same goes for any of the other few on my list.

Anyone else down for an engine rub down? beagle killer?? hip hop boy?

Originally Posted by E46Mango

Alex is definitely on my list. (And not my block list--I took him off)

One day I'll place my hands underneath Alex's intake manifold and feel around to make sure everythings OK. I'll also touch other parts of the engine bay. If I see any dirt on my hands after an engine rub down, his name gets erased off the list. Same goes for any of the other few on my list.

Anyone else down for an engine rub down? beagle killer?? hip hop boy?

Mine can use all the rub it can get, Dmax' too... being on the darkside of the moon and all. Watch out for the "Love Kit" in the trunk though, with items like Gorilla Tape (strong enough for a beagle) rope etc...

"Beware of any man who keeps a Love Kit in his trunk."