2002 S40 1.9d turbo engine "clacking"

[GazHill1987]

Hi all,

I apologise if this isn't quite the right place to post this, I've used the search option but I can't find anything specific that's related to my problem. I figured I'd ask the experts on here.

My dad's S40 is making what I can only describe as a fairly audible "clacking" noise coming from the engine, similar in sound to a snooker/pool ball hitting another ball but with a metallic hint. The car has done roughly 160k miles and it's always sounded typically diesel-ish, but it's never made a noise as noticeable as this. The turbo sounds alright but to be fair I haven't heard a bad turbo before.

He's taken it to the local mechanic who said that he thinks it could be the camshaft creating the noise, apparently he used one of those stethoscopes. I've had a bit of mechanical experience with cars so I said I'd have a listen.

After listening to the engine for a while I thought perhaps it needed some oil, I checked the dipstick with the correct procedure and found it to be on minimum so I topped it up to about half way between minimum and maximum - the engine carried on making the same noise.

I then took off the camshaft cover and examined the cam lobes themselves, they looked well lubricated and I couldn't see any signs of wear or interference with anything (in case they were catching.) I tried moving the camshaft itself and examined the bearing housings but everything seemed secure with no cause for concern. The tappet buckets seemed fine as well from what I could see.

I put the cam cover back on and started the engine again, feeling where the issue was coming from, I could feel it feintly on the cover but I could feel it more further down underneath the injectors.

I had a listen around the back of the engine and it sounded more noticeable from that position, whether that's because there's less stuff to get in the way which dampens the sound or what I'm not sure, but I was thinking perhaps it was the end bearings wearing, piston slap or something like that, it's very metallic sounding.

The trouble is he's afraid to use it now, and he doesn't want to spend £400 getting the cam done when it's not forced to be that.


Maybe you get a million of these, if that's the case then I'm sorry, but if you have any ideas or simple checks for us to perform then they'd be much appreciated. Thank you for your time.

[gatos]

Any chance of a recording of the noise? Sounds really baffling

[Baffler]

When was the cam belt last replaced? If the tension on the belt has become slack it may have slipped a tooth, throwing the timing out. Unfortunately, these are interference engines so if it has slipped you may have done some irreversible damage.

[GazHill1987]

It sounds exactly like this when he revs it in the video, but it's constant, it increases and decreases in tempo in relation to the revs. Hear the sort of metallic clacking sound when he revs it in the video?

+ YouTube Video

I know the engine is different in the video but it sounds exactly like that.

[skyship007]

It sounds like a diesel does if the oil is too thin due to fuel contamination or the use of the wrong viscosity oil. What type and viscosity of oil are you using and when was it last changed??

[GazHill1987]

Bizarrely it's fixed itself now :S. I wonder if the oil top up helped it? He said he's going to change the oil and put some fuel engine flush through it.


Thanks for the replies everyone

[skyship007]

Originally Posted by GazHill1987

Bizarrely it's fixed itself now :S. I wonder if the oil top up helped it? He said he's going to change the oil and put some fuel engine flush through it.
Thanks for the replies everyone

Be carefull flushing the engine because if you use something too effective it can easily damage something. The only safe product in my opinion is the standard Liqui Moly flush that is added just before the oil change. The engine is then left to idle for 10 minutes before the oil is drained.
Make sure you use a good quality 5/40 and a real Volvo oil filter. If the oil is sludgy it is safer to do a double oil change to clean out the engine rather than play around with engine flush additives, if you use a good full synthetic it will clean the engine anyway over the new few oil changes.