I'm using the product now in my Benzes. I usually stay away from oil additives, but I had to give this one a try because from my experience Bar's Leaks makes good products and I was curious about this one. It's not really an oil additive; it's more of an engine treatment. It's supposed to clean the rings and (temporarily) fill in scratches that may be present in the cylinder walls.

In my 240D I have not perceived any changes. The compression and rings were probably already OK. In my E300D, my #1 injector suddenly clogged the day after I installed the additive and I had to have the car towed home because it had a horrible knock and I didn't want to destroy the engine. All is well now and I don't think the incident was related to this additive, but who knows. The only possibility I can think of is that maybe the rings were sticking in this cylinder and the cylinder had carbon deposits and this additive freed the rings and the suddenly higher compression blew out the carbon and some of it got stuck in the injector nozzle's pintle. More likely (but still unlikely) a large chunk of carbon from the intake (thanks to the EGR) got loose and ended up choking the nozzle pintle. Even more likely, it was just a bad coincidence and for some mysterious reason the injector decided to stop working.

Afterward I disassembled the injector, cleaned all the components, put them back together and the injector was then spraying fine so I reused it. The knock on that cylinder gradually went away. Now about 1-2 months later all is still well. As to this additive, I still believe it can work when the problem is sticky rings or minor scratches in the cylinder walls, but I probably won't use it again because I don't think I need it.

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2004 VW Jetta TDI (manual)

Past MB's: '96 E300D, '83 240D, '82 300D, '87 300D, '87 420SEL