Going to put in Rotella 15-40 and Marvel Mystery oil (MMO) tomorrow.Performed the head gasket repair and used cheap oil I had to clear everythingout. Have the new Purolator filter too. I'm wondering if the MMO burns throughthe system or stays and whether it may possibly affect the smog test. I alsoput in decent plugs and the Magnecor 8mm. Thanks to anybody who’s ever posted,especially the 'señor' members.

 

MMO in fuel or MMO in oil system? If in fuel certainly burns thru, if in oil it works as a solvent (it is about 7 weight). Doesn't make codes in my vehicles, I live outside the smog zone (surounds our state capital, Atlanta, which is famous for hot air).

 

Sorry, oil. Would the 7 weight therefore affect the oil pressure at temp

 

You would need a better gauge than comes in a Disco to see it. Not so much, you are only diluting the oil very slightly.