Never use PTFE in a Mercedes engine!!!
Frank King, the Technical Editor of The Star Magazine, wrote about this in the November / December 1992 issue.
"Mercedes Benz statements that additives may impair the quality of your engine oil, and that those containing PTFE are particularly unacceptable-have often been repeated.
Several tests were conducted on additives containing PTFE and increased wear developed in the critical area between valve stems and camshaft. The record showed no increase in engine power and no fuel savings, and a higher rate of wear on piston rings. PTFE is also a solid and can block oil passages, which are expecially critical in an engine engineered to such tight tolerances as a Mercedes Benz engine.
Castrol's experts have observed in their test engines a layer of fluoride, which causes higher friction and favors corrosion. In addition, substances which contain PTFE at temperatures above 400 degrees Celsius decompose and can give off poisonous hydroflouric acid.
Such alarms have also been raised by the German Federal Environment Office, which says, "The inclusion of PTFE as an engine oil additive leaves...toxic compounds from the expected decomposition...and is therefore....rated as detrimental.
2001 E430, Bourdeaux Red, Oyster interior.
1973 280SE 4.5, 170,000 miles. 568 Signal Red, Black MB Tex. "The Red Baron".