Help: Strange noise from the engine bay - The Unofficial BMW M5 Messageboard (m5board.com)

tiger740 · 29th April 2009, 03:35

Hello,

While I was driving, my car developed a strange noise in the engine compartment - it sounded as if something was very loose (lots of parts cranking or banging against each other) and as if the entire front end was about to fall apart. The car is now significantly slower and makes very loud cooling fan noise at the same time as if I am driving a tank.

There was no check engine light and the coolant temperature remained neutral.

If I remember correctly, this happened on the day when I first turned on the A/C.

Any help would be appreciated.

tiger740 · 29th April 2009, 06:46

Anyone, please?

jrhaile · 29th April 2009, 07:08

fan clutch? Did you even open the hood? Anything look broken? Low oil? Oil in your coolant or anything? Go run any codes? Spark plug(s) backed out?

Need some more info dude...

tiger740 · 29th April 2009, 07:16

I have opened the hood and looked around, but nothing I could tell. I just changed oil two weeks ago. What is fan clutch?

jrhaile · 29th April 2009, 07:18

Quote:

Originally Posted by tiger740

I have opened the hood and looked around, but nothing I could tell. I just changed oil two weeks ago. What is fan clutch?

Open your hood and look down.. there is a big fan blade which is attached to the fan clutch which is bolted onto the waterpump pulley. Spin that fan and see if all of the blades are still in tact. Report back.

If it was a backed out spark plug I would imagine a SES light of some sort so I doubt that's it.

jrhaile · 29th April 2009, 07:20

Also can you rev the car while it's not moving and hear the noise? Where is it coming from? An obvious thing upfront that can cause loud noises is a vanos breaking but I've never heard of it just breaking while driving. A timing chain snapping would cause some major issues as well that I would imagine would stop the engine all together

Possible chain tensioner allowing the chain to slap the block would be my next guess.

Tho///a5 · 29th April 2009, 07:21

it was probably a bat living in the AC unit. It was probably trying to escape but was chopped to bits on exit by the fan. haha jk

good luck man sounds like it might be internal, but i'm sure it's something small.

tiger740 · 29th April 2009, 07:25

Thanks so much. The car is significantly underpowered and slow, let alone the discerning noise it makes. I will check it to the shop tomorrow. I hope that it's something small - no check engine light whatsoever...

jrhaile · 29th April 2009, 07:28

Quote:

Originally Posted by tiger740

Thanks so much. The car is significantly underpowered and slow, let alone the discerning noise it makes. I will check it to the shop tomorrow. I hope that it's something small - no check engine light whatsoever...

The fact that you get no SES light makes me think it isn't something too big but you just never know. I would seriously consider having it towed though just to make sure.

Report back with your findings...

tiger740 · 11th May 2009, 05:42

So, I went to a BMW mechanic several days ago and the only faulty items that they found were aux. waterpump (code stored in the computer) and leaky power steering line. They said that they could not replicate the problem. I had them replace both, but did not solve this problem. It's still there all the time when the car is hot.

Just to be specific, when my car is fully warmed up and hot, there is a strange creaking, rattling noise coming from the engine compartment while driving.

- The noise does not become louder or softer depending on the RPM

- The noise is there even on a smooth road

- Only comes out when the engine is hot (no check engine light, coolant / engine temperature perfectly in the middle)

I am still so confused. Anyone had the similar problem?