Engine - Warning About Carbon Cleaning

To: OUR MERCEDES-BENZ PASSENGER CAR DEALERS

DATE: May 1990

FER.NO. MENA 00/39

SUBJECT:
USE OF ENGINE CLEANING CHEMICALS

It has recently come to our attention that authorized dealers are promoting the use of chemicals which claim to "clean" the intake valves, fuel injectors, combustion chamber, etc., from carbon build-up.


Please be reminded that MENA does not approve of the use of any of these products, or any fuel additives for gasoline engines on our vehicles (see S.I. MENA 00/38, January 1990 and latest edition of Specifications for Service Products microfiche).


Many of these products claim results which are questionable, and the high concentration of these products can cause engine damage due to chemical reactions in the combustion chamber and on the cylinder walls.


The use of these chemical "cleaners" is also not approved due to the potential toxic risks to the user and environment.


The best way to prevent any build-up is to use a reputable brand, high quality fuel which contains all the necessary additives and detergents and to adhere to the recommended lubrication and maintenance service intervals.


Warranty claims for engine failures attributed to the use of cleaning chemicals or non-approved fuel additives will be rejected.


Please advise your customers accordingly.