Guys, what is this brown film that seems to be coating everything inside the engine? I run M1 oil and a good filter, and change frequently so I can't believe that the engine is sludged. It's never overheated. I can put my finger down inside the oil fill hole and rub a rocker arm, and the film comes off onto my finger. What is that crap, and can it be cleaned out without tearing down the motor? Thanks.

Car is an 88 IROC, LB9, 155k miles.

 

How long have you been using M1?

Unless from when the car was new, you're looking at varnish left over from the petroleum oil previously used. It can take a long time to get rid of it all. I have a '90 Bonneville SSE that I got when it had 104k miles, it's got 180k on it now, every one of those 76k that I've had it with AMSOIL, and there's still some left.

 

I've been using M1 for 3 or 4 years. I'm the original owner of the car, and yes, I used to use dino oil in it.

I'm thinking of switching over to the new M1 Truck & SUV oil. It's a 5W-40 oil, and I hear it's repackaged Delvac diesel oil. And I hear that diesel oils have even more cleaners in them. Additionally the thicker oil should help with my consumption problem.

Whatcha think?

 

Probably not a good idea.

Stick wth the M1 10W-30, it's just fine.

I wouldn't worry about a "brown film".... it's mostly combustion residue that has builtup in there.... now a black thick slime, that would be a different matter; but it's about impossible to keep a gasoline motor from accumultaing some of that varnish. It's not hurting anything.