C250 TD Noisy cold start

[Griz]

Hello everybody.
I`m new to MB`s I really love this car and I love the smooth engine`s powerful and querky sound. (sounds like an inline six with attitude?) Its done 125,000 mile`s and I`ve had it for 3000 miles, It`s got a full service history, although I`m not keen on 12`000 to 14,000 mile service intervals! The other day I had the lid up to check the engine oil first thing in the morning and I started the engine to warm it up before going out and I noticed a noise at the front of the engine (timing chest area) it lasted for about 90 ish seconds then suddenly stopped. Since then I always cold start with the bonnet up and it always makes the same noise? It sound a bit like regular timing chain rattle as though the chain tensioner is`nt working, but there is no noise from the tappets so oil pressure must be ok. IS IT ME ? Am I being paranoid or is there something I should know ?

Thanks for any advice you may have. Griz

 

[Ellsy Tanners]

It could be the belt tensioner or the damper for the belt tensioner, press down on the damper and see if the noise goes.

 

[Griz]

Thanks for that, but it stop`s after 90 seconds. If it was something worn out (ball, roller bearing etc) it would be getting worse and so far it isn`t!

 

[dougjoy]

Are you sure it's not the hydraulic cam followers, some of them need to refill with oil after being left overnight.

What oil are you using in the engine, I used to get it in the morning but cured it using Mobile 1 fully sythetic 0W-40 protection formulae. Not cheap but worth it. The engine seems to run quieter as well.

 

[Griz]

Hi Dougjoy

Yes! I think you`re right, I went to see MB at Lincoln and spoke to the service manager who said there are no known faults with that engine so he did`nt have an idea what it might be without hearing it. He did say I could leave it with them overnight and they would have a listen to it in the morning to diagnose the fault. (free of charge !) But I had a 1.9 TDi Golf that suffered from sticking hydraulic followers, it sounded like a bag of spanners in a washing machine until I put some Wynns hydraulic valve lifter treatment in the oil. Sorted it in about 50 miles. So I quizzed the MB tech man who said it won`t do any harm. I put the treatment in today and I have to say it sounded better after about 10 miles, but I will see (hear) what happens tomorrow morning. Its still running on the MB oil which I hope is good quailty but I will be changing it to Castrol Edge TD 5W40 if this works.

Griz

 

[Griz]

Hi Dougjoy, I took your advice and splashed out on some Mobil 1 "OUCH" but it will be worth it I`m sure !

 

[dougjoy]

It worked for me, all other oils seemed to last 5 - 6K miles and then the rattle would come back. With the mobile 0-40 8.5K and still no rattle in the morning.

Hope it does the same for you.