Quote:
Originally Posted by ah-kay
I am curious as to why there is a sound from the EGR valve when I release the throttle. The EGR valve is shot? I have 3 other cars with the same OM603 engine in the yard and none of them make the sound.
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Either theres a vacuum leak in the valve or a clogged valve. Without a hand vacuum pump or removing it its hard to tell.
Quote:
Originally Posted by Shortsguy1
Some have pointed out the gunk does not actually affect performance all that much, so I am not sure what MB engineers envisioned. Perhaps they thought it would stay perfectly clean because new engines have lower PM and lower oily blowby. Or perhaps they knew it would gunk up but figured it didn't matter much overall.
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Removing the black tar like substance from the manifold and intake ports makes a very noticeable performance difference. The Mercedes engineers correctly calculated that EGR buildup wouldn't be a problem until after the car was out of warranty when it would no longer be their problem. In most markets these engines were sold without it. EGR was a bandaid to meet US emissions.
No performance difference? HA
Also keep in mind that the more you restrict the intake with the EGR/crankcase vent tar, the more smoke your engine will produce under acceleration. Its a self defeating system that eventually increases HC emissions. Whether or not you believe in keeping the EGR functional (I'm not going to argue either way), its worthwhile to clean the manifold and intake ports for lower emissions and improved economy.
Parting shot: Whatever happens to a Mercedes diesel engine, its 10 times worse on a VW TDI.
