Sprinter engine noise

[Tim2005]

Hi all, newbie here. I wonder if anyone can assist, or direct me towards a Mercedes van forum. I have a 1996 Sprinter 212, (2.9 5 cyl td & intercooler), 160000 miles, it's great, has been well maintained, everything is fine, uses no oil, gives good fuel mileage & goes like a jet. Last serviced about 5000 miles ago. I have had it for a couple of years, 1 previous owner. However, about 1000 miles ago it started making a noise, sounds just like a loose tappet, but only does it when it has been under load for a while. For instance run it along a motorway for 10 miles at 70-80mph or more (cough), then pull off up the slip road & you can hear it inside the cab very clearly. Leave it ticking over for 2 or 3 minutes and it is gone, runs quiet as can be. That makes diagnosis very hard indeed. It seems to be coming from the top of the engine, maybe middle or rearwards.

Assuming it was a hydraulic tappet playing up, I replaced them. No difference. Cam etc is in great condition, chain is nice and tight too. Next idea, suggested by a diesel mechanic who has heard the noise, was that it may be an injector- I've had them professionally removed, cleaned and reset. Made no difference at all. The injector nozzles are not A1, but at £350 a set (and as the injector clean & reset made no difference), I'm reluctant to try that, especially as the problem has no other symptoms - performance, fuel mileage and everything are all totally unaffected. Maybe I should just turn the stereo up and ignore it! Any ideas anyone??

Many thanks


Tim

 

[dieselman]

It could be either the EGR valve opening too much, a poor spraying injector, air being sucked into an injector pipe.
It sounds combustion related, and yes it can sound like the motor is splitting in half.

 

[c250 turbo diesel]

Rattle

Hi, could be your belt tensioner system, mainly the bottom end of the small hydraulic piston, when you have the rattle again get a long screwdriver, put behind the bottom of the piston and lever out (tension it) the bottom bush is prone to going, if the rattle stops, you have found your problem, I had the same on a 310 sprinter, and you would have thought it was an internal problem.

Be warned if that piston is knackered, you will need to replace all ie belt, spring, main swivel housing, and the two plastic pulleys, as everything else wears badly . £200 WORTH OF PART,S AND HARD TO DO ! just done one mate Roy

 

[Yeti]

Goody gumdrops.

I have this same problem.