[Xtremektm]

Engine make a strange noise, sound like an old ford 350. Is like a tapping noise that disappear when remove the belt. The crankshaft damper, water pump and belt tensioner are new. I suspect maybe the power steering pump is bad but never saw a ps pump make that kind of noise.
Any advice please.

[Yozh]

Hard to judge, but that close to the engine it sounds normal. Do you get excessive noise inside the car and with the hood closed.

[GreekboyD]

I'm assuming this is your first diesel?

[demon]

compared to my old diesel jetta the BMW D is QUIET!

[sukutash]

Sounds like it should. Hard to tell with recorded audio though.

[Hoooper]

I guess Im the only one that things it sounds weird. Its too fast to be the normal engine clatter I think. Plus if it goes away when you remove the belt its not engine noise anyway. Sounds like its coming from the passenger side. I would suggest removing the intake tube that runs over the radiator and taking a closer look while its running.

Also, pull the oil cap while its running and see if it gets louder. I dont think its the vacuum pump noise (and shouldnt be if it goes away with the belt) but who knows

[kiel_dafo_kenyg_as]

I think it's the vacuum pump. Remove the oil cap. Does it match what you hear and does it get louder?

[dumalei]

I have this same noise too when I stop at a light or sth but not very loud. I thought its normal.

[Xtremektm]

Yes i thinking maybe be the vaccum pump is going bad but does not get louder when remove the cap, only get quiet when remove the belt. For that reason dont think the noise is normal. Since the water pump and belt tensioner are new the only option is a bad ps pump.

[dumalei]

Is it something that we can replace ourselves?

[Hoooper]

Its probably not the vacuum pump if the noise isnt louder with the oil cap off and it does go away with the belt removed. If you pull off that intake tube across the top it should be easy to pinpoint the sound. No harm in running it after removing that tube if youre concerned, the air still goes through the filter.

[dumalei]

Is it okay to keep it like that until sth goes wrong (SES lights comes up or sth)then we will know what need to be fixed?

[Xtremektm]

Yes i remove the intakes tube but cant find where the noise is comming. Went to different independent shop and just spend money on parts and labor but car still the same. First one told me that the water pump was making the noise, change it for an original and nothing. Then other shop told me that the belt tensioner, change it and nothing. Now only have three option, ps pump, alternator or idle pulley. Alternator and idler pulley wont make that kind of noise when go bad, only option is the ps pump but is almost 500 dls to change it without knowing that this is going to fix the problem.

[Hoooper]

Originally Posted by dumalei

Is it okay to keep it like that until sth goes wrong (SES lights comes up or sth)then we will know what need to be fixed?

well you should check yours on your own and go through the steps to figure our where the sound is coming from, but if its the PS pump you probably wont get a light until it fails and only if it locks up and sheds the belt. I would guess you would know something is wrong well before you get a light.

[Hoooper]

Originally Posted by Xtremektm

Yes i remove the intakes tube but cant find where the noise is comming. Went to different independent shop and just spend money on parts and labor but car still the same. First one told me that the water pump was making the noise, change it for an original and nothing. Then other shop told me that the belt tensioner, change it and nothing. Now only have three option, ps pump, alternator or idle pulley. Alternator and idler pulley wont make that kind of noise when go bad, only option is the ps pump but is almost 500 dls to change it without knowing that this is going to fix the problem.

I dont know what the belt routing looks like, but would it be possible to use a shorter belt and bypass the power steering? Assorted belts only cost about $20 at the parts store, that would be a fairly cheap diagnosis. The shops should have been using a stethoscope, pretty easy to tell when using one.

[Xtremektm]

Originally Posted by Hoooper

I dont know what the belt routing looks like, but would it be possible to use a shorter belt and bypass the power steering? Assorted belts only cost about $20 at the parts store, that would be a fairly cheap diagnosis. The shops should have been using a stethoscope, pretty easy to tell when using one.

Yes, shorter belt is a good idea to bypass the PS. I will try this, just need to buy a tool to remove the a/c belt.

[Yozh]

Originally Posted by whiteblue

I think it's the vacuum pump. Remove the oil cap. Does it match what you hear and does it get louder?

Shouldn't your brakes be affected if the vacuum pump is going bad?

[glitdi]

take a really long screwdriver or some type of prybar, and hold against various rotating housings such as the vacuum pump and power steering etc. hold the plastic handle end to you ear and you can isolate where the sound is coming from.
Sounds more like timing related start of injection than rotating noise, could be due to load on the alternator, could be the engine compensating for poor fuel or fuel temps etc.
Good luck!

[BB_cuda]

Originally Posted by glitdi

take a really long screwdriver or some type of prybar, and hold against various rotating housings such as the vacuum pump and power steering etc. hold the plastic handle end to you ear and you can isolate where the sound is coming from.
Sounds more like timing related start of injection than rotating noise, could be due to load on the alternator, could be the engine compensating for poor fuel or fuel temps etc.
Good luck!

I've watched my dad use a cut off broom stick. Stethoscope at auto zone was around $15 if i recall. I used it to listen to differential that sounded like a cement truck. I also listened to outboard axle bearings and they sounded fine. Valuable tool that will get future use.

Don't know if any other 335D folks live near you but a side by side comparison would be interesting since the microphone may be real sensitive. We can't tell what a normal sounding engine would be like on your phone. Sort of a reference to compare to.

[toy_soldier]

Did you figure out where the noise came from? My 335d just started to develop the exact same noise. It goes away if i let the car idle for 5 minutes in the morning.

[Goboro100]

Originally Posted by Hoooper

Its probably not the vacuum pump if the noise isnt louder with the oil cap off and it does go away with the belt removed. If you pull off that intake tube across the top it should be easy to pinpoint the sound. No harm in running it after removing that tube if youre concerned, the air still goes through the filter.

Hooper I have this small noise I’m getting. It’s basically a very light tick at idle. Inside the car you can’t hear anything. No CEL lights on. Car runs strong and pulls like a train. While idling if you ignore the light ticking sound it’s perfect. I will open oil cap to see if it gets louder tomorrow. I hope it’s not oil pump. Or timing chain. 84k miles. Engine oil is fresh and car is maintained well recently tuned but sound was there prior has not progressed. Bellt and pulleys are original. Water pump, power steering and others all are original. Some say vacuum pump... I wanna diagnose this ASAP should I get one of those ear doctor things?

[Nadir Point]

I'm at 134k miles with the original belts/pulleys/etc. Don't fix it if it ain't broke.