There has been a lot of activity here regarding the A.C. Delco product ‘X-66’, also known as ‘top engine cleaner’ by the G.M. dealerships.

I believe that there may be a misconception as to its proper use. And *proper* use is essential. Although it is available in a liquid form, it needs to be known that this is NOT a traditional fuel addititive. DO NOT, under any circumstances, add X-66 to your gas tank! I can only guess as to the consequences; but I would not be surprised if you would have every rubber line & O-ring in the fuel system *melt* from the inside out. And if the possibility of self-immolation is not bad enough, the garbage resulting from the breakdown would likely plug every small orifice in the system, i.e., injectors, pressure regulators, etc., etc. (And the fuel distributor in the case of CIS cars).

Also, this is VERY nasty stuff. Please look at the safety precautions I posted in the following thread: Delco X-66 de-carbonizing agent


[Edited by RunningTooHot on 07-05-2001 at 06:19 PM]