I recently posted regarding my sprinter van problem. Firstly thanks for all the suggestions. For those who did not read the original thread: I have 312 1999 sprinter 73K on the clock, and loads of services and oil changes (2.9 straight 5 turbo charged).
While driving I get a “tappet noise”(normally when on a motorway, while fairly motoring). This noise would disappear after a few minutes (providing you pulled over and let the engine idle). After talking to a few friends (all are qualified mechanics) the conclusion was that one or some of the hydraulic tappets were loosing pressure, and need to be replaced. So off to the local merc dealer, cheque book in hand and replaced all 10 tappets. So off for a burn on the motorway, and sure enough the same thing happened, sharp Tappet sound after a few miles on the motorway. So rocket cover off (again) cam and tappets removed and all oil chambers blown out with compressed air (oil filter removed). Cam and lifters (tappets) refitted, no sign of any wear whatsoever, and started the engine… sounds sweet….left to idle for a few minutes, up to working temp, all sounds OK and off again for a spin on the motorway, and sure enough tappet tappet tappet sound………………….At this stage I was willing to give up, until I spoke to a Welsh mechanic who looks after a large fleet of trucks…….after explaining the symptoms his first response was “what oil have you in the engine” and I explained I used semi synthetic oil (10W40) as recommended by Merc. He suggested changing the oil for Castrol ELIXIR 5W50 (pricey oil!), and guess what PROBLEM SOLVED no more tappet sounds…sweet…. can anybody explain why ??????
While driving I get a “tappet noise”(normally when on a motorway, while fairly motoring). This noise would disappear after a few minutes (providing you pulled over and let the engine idle). After talking to a few friends (all are qualified mechanics) the conclusion was that one or some of the hydraulic tappets were loosing pressure, and need to be replaced. So off to the local merc dealer, cheque book in hand and replaced all 10 tappets. So off for a burn on the motorway, and sure enough the same thing happened, sharp Tappet sound after a few miles on the motorway. So rocket cover off (again) cam and tappets removed and all oil chambers blown out with compressed air (oil filter removed). Cam and lifters (tappets) refitted, no sign of any wear whatsoever, and started the engine… sounds sweet….left to idle for a few minutes, up to working temp, all sounds OK and off again for a spin on the motorway, and sure enough tappet tappet tappet sound………………….At this stage I was willing to give up, until I spoke to a Welsh mechanic who looks after a large fleet of trucks…….after explaining the symptoms his first response was “what oil have you in the engine” and I explained I used semi synthetic oil (10W40) as recommended by Merc. He suggested changing the oil for Castrol ELIXIR 5W50 (pricey oil!), and guess what PROBLEM SOLVED no more tappet sounds…sweet…. can anybody explain why ??????
