Loud noice coming from engine block when cold?!

Hi,

I have had my 645 a couple of weeks now.
Yesterday morning I noticed some very weird noise coming from the engine itself (it seems).
It's a loud almost metallic noise and doesn't follow the engine when revving. It goes on for about a minute and then disappears. What can this be?

A mechanic told me that this car has an exhaust fan that goes on when the engine is cold. Can this be it? Is it loud or is it barely noticable?

It might be noise coming from the valvetronic system trying to sync, or could be coming from the secondary air system. Both only run when the engine is cold, they run around 1 minute then shutdown.

So I shouldn't be worried then? I actually left the car at the shop today so they can check if there's something wrong.

I bought the car a couple of weeks ago and I don't think I've heard the sound/noise before when I start the car (although I'm not 100% sure).

These engines make some noise that you can here with the hood open, but you should not hear much noise in the car. Carbon buildup will also cause noise when the engine is cold. If you put a couple of bottles of Techron in the fuel tank, it should help clean out the system. It's hard to tell what your noise is, without being there.


Good Luck!

I uploaded a video of the symptom:


Note that after 0:25 the sound disappears and it's a significant decrease in the volume.

Wow. That is some noise and goes away at 0:25. The engine was still running after that right?
It's really hard to tell from a recording what the issue could be. I would definately have it looked at.

That don't sound good. Possibly something going on with the secondary air pump system. Have it looked at!

Originally Posted by TxTaz

Wow. That is some noise and goes away at 0:25. The engine was still running after that right?
It's really hard to tell from a recording what the issue could be. I would definately have it looked at.

Yes the engine is still running. As I said earlier I left the car at the dealer today to have it looked at, will report back on what they find.

Originally Posted by HerbP

That don't sound good. Possibly something going on with the secondary air pump system. Have it looked at!

What does the secondary pump system do?

All it does is mix air flow & exhaust while cold, to meet emission standards for the EPA guru's. After listening to it with a better internet connection, it might be a water pump or alternator bearing going out. You have a problem that needs to be addressed!

Good Luck!

Wow, a video is worth more than a thousand words in this case. That is loud! The one good thing is the mechanic should have no problems pinpointing the source.

I have never heard anything like that before so I am not even going to attempt to guess what it is.

Originally Posted by HerbP

All it does is mix air flow & exhaust while cold, to meet emission standards for the EPA guru's. After listening to it with a better internet connection, it might be a water pump or alternator bearing going out. You have a problem that needs to be addressed!

Good Luck!

Well, I really don't think that it has anything to do with neither the water pump or the alternator. You can hear that when the sound disappears, it's almost like something is spinning down and also from what I can hear it doesn't come from that area of the engine.

Originally Posted by Yorgi

Wow, a video is worth more than a thousand words in this case. That is loud! The one good thing is the mechanic should have no problems pinpointing the source.

I have never heard anything like that before so I am not even going to attempt to guess what it is.

I'll let you guys know what the mechanic finds! hopefully nothing too expensive...

I got the car back from the dealer today.

Apparently it was a valve in the secondary air pump system that didn't open and close properly. He disconnected the air pump and the sound disappeared. I will go back to the dealer to have the part changed once they receive it in stock, but since it doesn't affect anything else but the emissions the first couple of minutes I really couldn''t care less (thinking about skipping the replacement valve and just leave it as it is)

Take a look at this diagram. The pump is $344 and the air valve is $95.
I'm sure it beats the dealer price if you can wait for it.

Originally Posted by TxTaz

Take a look at this diagram......

Hey Taz, how do you get that diagram version of the parts at Tischer? I have not figured that one out.

Originally Posted by TxTaz

Take a look at this diagram. The pump is $344 and the air valve is $95.
I'm sure it beats the dealer price if you can wait for it.

Thanks, but I'm not sure it will be that much cheaper since I live in Sweden. Except the shipping fee I have to pay 25% import tax from the US (stupid EU rules )

Originally Posted by jacobsweden

Thanks, but I'm not sure it will be that much cheaper since I live in Sweden. Except the shipping fee I have to pay 25% import tax from the US (stupid EU rules )

OK for you EU guys try here.

Originally Posted by Yorgi

Hey Taz, how do you get that diagram version of the parts at Tischer? I have not figured that one out.

Uhhhmmm, I dunno. I just clicked a few buttons and there it was.

Go here and click the view illustration button.

edit
OK, scratch that. Links to their component pages fail to work but to the specific diagram does.

Sounds like a defective muffler bearing!

Originally Posted by Dynamicfigure

Sounds like a defective muffler bearing!

If you read my other post I have already been told by the mechanic that it had something to do with the valve for the secondary air pump system

Originally Posted by jacobsweden

I got the car back from the dealer today.

Apparently it was a valve in the secondary air pump system that didn't open and close properly. He disconnected the air pump and the sound disappeared. I will go back to the dealer to have the part changed once they receive it in stock, but since it doesn't affect anything else but the emissions the first couple of minutes I really couldn''t care less (thinking about skipping the replacement valve and just leave it as it is)

......
hi read ur post i think i have the same problem with my car. any chance of sending me the video that u uploaded if u still have it . as everytime i click on it it says the video no longer excist .
if you know longa have the video if i upload my video to you. do u think yourl still remember what the noise was like.
thanks dan

my normal email addres is simpkin.dan.ds@gmail.com
if you could contact me threw this it would be easier thanks