sprinter problem

[ianmaxtec]

Hello,

I am new to this forum. I have a 1999 312 sprinter with a 2.7 5 cylinder turbo charged engine. My problem is when on the motorway at high speed I start to hear a tappet sound from under the rocket cover. After numerous discussions it was decided that the problem could only be leaking tappet lifters. So the rocket cover was lifted, crank removed and all 10 lifters replaced.... pretty easy job, and it turned out that 2 lifters were leaking and not holding pressure. So off to the motorway for a burn, and the tappet noise returned after cranking up to 80mph for a few minutes. The noise does go away after a few minutes, providing that you ease off the power. At this stage I am lost. The noise is most certinally from the tappets, yet everything seems fine. The van only has 73k on board, and 10 full services along with app 25 oil / filter changes. When the rocket cover is removed the top of the engine looks new, no stains or build-ups of any kind, clean oil and nothing but shiney metal. It has now been suggested that it might be the injectors.

ANY suggestions would be welcome.

thanks in advance

ps: excuse any typos

 

[Sprint'n'Go]

Hi and welcome to the forum.

First of all I think you will find that your 99 312 is a 2.9ltr engine, The 2.7CDI units were introduced about a year later in 2000 or 2001. As for the noise you are hearing if it has been investigated by a competant mechanic and tappets are the only thing they can suggest then I would ignore it. I hear/imagine all sorts of rattles,hissing,knocking and tapping from my van engine at various speeds and loads and I think they are caused by listening too hard for too long. Don't forget that what you are driving is a commercial diesel vehicle and has limited sound insulation when compared to the passenger cars.

The engine in your van has an enviable reputation for longevity and reliability, more so than the later CDI units which appear to be prone to injection problems. The only thing that puzzles me about your van is the number of services it has had. If the mileage is correct it has had an oil change approx every 3000 miles or every 3 months which appears to be a case of massive over servicing. Have you ever found a reason for this?

Sorry I can't be more help.

 

[ianmaxtec]

Reply to Steve,

Thank you for the warm welcome.

The reason this van has been “over serviced” was to try and avoid problems, like the one that has arisen. Believe me when I say this is a new sound, that has appeared out of nowhere, its not diesel knock, or pinking, it most definitely sounds like the tappets in my old manta A when they went askew. It can at times be very severe, and will slowly vanish as you ease off the power (takes a couple of minutes). I should explain that I am the only one who drives this van, and I am well used to the way it “should sound”
Most diffidently something is a miss.

Thanks for your reply

Ian

 

[c250 turbo diesel]

When you hear the noise next time if stopped get a long screwdriver an put behind the belt tensioner damper, and put ouward pressure on it, this can sound like a bad tappet noise, and also come and go ! Roy

 

[IAN MAC]

Have heard of injector coming loose and sounding like a tappet, only lasted a few hundred miles though before it broke.!!!

 

[ianmaxtec]

Tried the injectors, loosened them just enough to leak fuel, and the engine would jump all over the place (tried one at a time obviously), anyway the tappet type sound was still there. I'll try the belt tension damper (thanks C250TD). I will post the findings!