This might be old wife's tale. Long time ago, I was told to use fuel system cleaner only right before oil change because the engine oil ends up contaminated. Does this make any sense (still)? I love Chestnut and would like to drive it for a long long time.

Arthur

 

I really do not think adding a can of Techron or other gas additive will get into the oil. Just about all of these additives mix fully with the gas and burn in the upper cylinder. Even all of the gas companys use additives.

I believe in using "Techron" in my gas tank every 10,000 miles to keep the injectors clean. Techron also is good at keeping the floats for the fuel gage free from sticking. It is good stuff.

Change the oil every 7,500 miles and use the proper oil and your engine will last a very long time.

 

I recall this warning on bottles of Techron in the late '90s. From my MB club days, I recall the discussion as follows;
Techron is basically a fuel dispersant, so it works by thinning the fuel this acts as a solvent to clean intake deposits. That is good. But what isn't good is the thinned fuel gets past the rings easier since it isn't wiped down as well, and you do get some contamination in the crankcase. Not a problem if you run a bottle through a tankful and then change the (now-thinned) crankcase oil.

I don't believe the problem to be too serious, but it's always better to be safe than sorry. You also don"t want to run several bottles /tanks through one oil change.

HTH

 

I have been running Redline SL1 for about 30 years. When using it the first time, it is a full bottle. When using it for maintenance, it is only 1 oz per 10 Gals. Redline is the only fuel cleaner recommended by BMW and is rebranded as BMW cleaner as well.