What the heck is he talking about? Yes I searched and read the thread. I have a 1991 190E 2.6 that runs great except for probably needing new valve stem seals.

brookspw

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1994 C280, dark green metallic
105k miles

1991 190E 2.6, Black
191,500 miles
(sold to another forum member)

2003 Chevy Tahoe LT, Redfire Metallic
105k miles

1989 Mustang GT Cobra Convertible
43k miles

There are a number of compounds used to remove carbon deposits from the cylinders and inside the heads of engines. Recommendations on what to use and how often vary. I have used RedLine “Fuel System Cleaner” with excellent results. I was astonished at the amount of crud that was blown out of the engine, as well as the engine idling better and running a tad cooler afterwards. If this has never been done, or even not done in 20K miles, you won’t be disappointed at the difference made. Generally you put in the treatment, fill up the gas tank and then burn up the tank on the freeway or other spirited drive. I like to drive to the mountains. At some point their will be a near mushroom cloud of debris to exit the tail pipe. That’s the carbon buildup getting blown out. The common wisdom is to change your oil right after running this tank of gas through the system as at least some of the deposits end up as particulate matter in the oil system.

Cheers

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...Tracy

'00 ML320 "Casper"
'92 400E "Stella"

Totally agreed with Lebenz.

I just cured the stubborn rough idle problem on my 92 400E by adding one bottom of Pennzoil fuel system cleaner and cruising on the highway on 2nd gear for a while.

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99 BMW 540i 6-speed 110K Km
03 SAAB 9-5 wagon 80K Km
92 400E (Sold) 245K km
Still missing the days with the Benz, it kept me busy.