Hi everybody

I'm driving a XFR '11. I bought it a couple of weeks ago. The car has now approx. 120'000 km. At the mileage of 100'000 km the chain and its tensioners plus all 4 VVT-Units were exchanged. Furthermore the SC coupler isolator has been exchanged.

I noticed a clacking noise after engine start at idle rpm (warm start). If I do a cold start of the engine the clacking noise isn't there (maybe because idle rpm is a bit higher comparing to a warm start). Strange is that after doing a warm start and increasing the rpm for a couple of seconds and the engine speed goes back to approx. 600 rpm again the noise goes away. In the video (link below) I recorded that behavior.
I tried to locate the noise with a stethoscope but everything sounds pretty normal to me (belt tensioners, VVT's, Supercharger, chain housing etc.) Only thing that was quite noisy (in my opinion) was the high-pressure fuel pipeline but the frequency wasn't the same as the clacking noise. So don't think it has something to do with that.


At the moment I suspect something with the oil resp. oil pressure because it behaves differently depending on the engine temperature even though no oil pressure warning occurs. I'm not sure what kind of oil that has been used at the last oil change. Probably in a next step I'm going to exchange the oil with the recommended Castrol 5W20 just to rule that assumption out.

Does somebody has ever heard about this kind of noise?

Thx in advance for every help.

 

Have you tried removing the accessory drive and supercharger belts to see if the noise changes or disappears?

 

Thanks for your reply. No didn't remove the belts yet. Will do that right after the oil change in case nothing has changed.

 

Unrelated, but it sounds like there's a slight knock on idle, although it could be exhaust I guess. Good idea to remove the belts to rule out anything else. I can hear the clacking noise, it sounds like maybe half the frequency of the HP fuel pipe, so maybe it's one of the two pumps has gone bad? There's an official program in the SDD software, as well as in some aftermarket code readers like my Autel, that allow you to disable the fuel pumps in turn at idle (since one pump can provide enough fuel for idle, providing you don't rev it) to rule out this issue.

 

Sounds to me like your s/c coupler is worn. You can buy a much more improved version of this on eBay for next to nothing - fitting it, required the s/c cover to be removed and then the snout must be removed from the supercharger - this little thing sits between the snout and the supercharger.
There are videos on YouTube on how to do the job yourself.
https://www.ebay.com/itm/Supercharge...YAAOSwEGVevH-G

 

Today I changed the oil but unfortunately nothing has changed. I will remove the belts as recommended in a next step in order to rule the auxiliaries out.

But honestly... I augur ill. I really think the oil pressure is too low at idle. But can't verify it because there are 2 special tools required for measuring it.

 

Did you ever figure this out?

 

My engine started sounding somewhat similar to this after replacing all of the cooling plastics and supercharger coupler and oil. Car runs fine but the noise makes me feel like something is wrong.

does anyone know what it could be?

I also have to 5.0 sc

 

Hi all
Some good news from my side - problem is gone. The only problem is that I don't really know what the root cause was. I kinda got used to the clacking noise after a while that's why I didn't realize it's gone.
Following things have been done until I realized that the noise is gone:

1. Changed motor oil (Castrol 5W20)
2. Exchanged AC compressor (because it was not cooling anymore)
3. Changed motor oil (Castrol 5W20) and used the Wynn's Motor Oil Cleaner*

*Add 325 ml of Wynn's Oil System Cleaner to the engine oil (3 to 6 liters) BEFORE changing the oil. Let the engine idle for 20 minutes. Stop the engine and change the oil and filter immediately.