Engine Noise! - The Unofficial BMW M5 Messageboard (m5board.com)

T Bone · 2nd March 2008, 23:01

I am getting a rattling / humm at idle. Enough that even my girlfriend thinks my car is a diesel. I have never heard this before and I haven't driven the car for a month until today.

The sound appears to be originating from the top of the cylinder heads towards the front.

Is this normal?

Venom77 · 3rd March 2008, 09:37

Mine makes a weird rattle sometimes as well... usually when the weather changes from hot to cold, goes away after warmup but its very noticeable outside of the usual rumbling diesel sounding startup...

I've not figured it out yet though, sorry...

unfoundhorsepower · 3rd March 2008, 14:37

OUTOWE.....Vanos???

6speed · 3rd March 2008, 15:25

I drove mine on Saturday for the first time in two months and had a similar noise but went away after driving a few minutes. My power streering was also kind of funky as I needed both hands to turn the car for the first turns. I guess she doesn't like to hibernate too much.....

Cheers ///

T Bone · 3rd March 2008, 18:04

Quote:

Originally Posted by 6speed

I drove mine on Saturday for the first time in two months and had a similar noise but went away after driving a few minutes. My power streering was also kind of funky as I needed both hands to turn the car for the first turns. I guess she doesn't like to hibernate too much.....

Cheers ///

Thanks everyone for responding..... I did a deep search after posting and it seems to be consistent with Vanos noise.

These things need to be driven constantly!!!

My appointment is Wednesday and hopefully they will purge the system.

A dark part of me wanted a new engine

Barry Lausch · 3rd March 2008, 18:49

Air entrainment in the vanos high pressure oil loop.........as you've discovered it will purge itself with use.

T Bone · 3rd March 2008, 19:19

Quote:

Originally Posted by Barry Lausch

Air entrainment in the vanos high pressure oil loop.........as you've discovered it will purge itself with use.

Thanks Barry for the info here and in the other thread.

NB · 3rd March 2008, 23:10

It could also be the Vanos Solenoid Valve, having mine replaced, after hearing what sounds like a chain on one of the plastic covers at the front of the engine where the vanos stuff is located.

I'm guessing many vanos issues will have that sound.

Also one of the parts is on back order to Germany, so I'm guessing that I'm not the only M5 to have had this issue with the vanos solenoid valve in the UK.

T Bone · 3rd March 2008, 23:16

Quote:

Originally Posted by NB

It could also be the Vanos Solenoid Valve, having mine replaced, after hearing what sounds like a chain on one of the plastic covers at the front of the engine where the vanos stuff is located.

I'm guessing many vanos issues will have that sound.

Also one of the parts is on back order to Germany, so I'm guessing that I'm not the only M5 to have had this issue with the vanos solenoid valve in the UK.

Thanks....it doesn't seem to affect power. Is there any potential for damage from driving on the street? On the track?

Cylinder Head · 3rd March 2008, 23:27

Normal, my car ticks away like a diesel always. Most unsexy idle in history. Good thing 8k rpms make up for it.

NB · 3rd March 2008, 23:37

Quote:

Originally Posted by T Bone

Thanks....it doesn't seem to affect power. Is there any potential for damage from driving on the street? On the track?

My sound comes and goes, generally, I'll drive to the shops, say 2 miles, I'll go round the shops get back into the car and this is when I hear it, only at idle or very light throttle, once warm it is fine.

The head tech at the dealer said if it was air it would happen more frequently. He mentioned a few different things that it could be, but he needed to check it out to be sure.

When they located the problem they did tell me it was safe to drive my car and there was no chance of damage to the engine.

My car feels as strong as ever, if not stronger thanks to the BMC and RPI scoops

...

Barry Lausch · 4th March 2008, 03:19

Vanos air entraimment has a sound all its own. I bet the tech a cheeseburger it wasn't air when it manifested itself in my 07 because it sounded metallic in nature and caused a vibration in the fore valve cover. (area where the vanos gear set lurks) I lost the bet. There is a bleed-off valve located in the sump near the vanos oil pump which provides for air attenuation in the system......when it's up and running