M20 Oil Choice - Synthetic vs Dino

[uscharalph]

I know this is a very heated subject. My 1989 E34 525i (M20) with 225,000 on the odometer has always had dino motor oil in it. I just got the cooling sytem solved and I had been contemplating doing a seafoam cleanout (oil & fuel) followed by converting to Mobil 1 Synthetic. Anyone have any specific experience ot suggestions.

[Paul in NZ]

at 225 miles ..hmmmmm.Its a fact that most engine waer occurs at start up.a 5w or 0w synthetic prolly gets pumped almost instantly greatly reducing engine wear

[BigKriss]

ditto. try synthetic and don't look back.

[brodee]

Mobile 1 15w50. Anything less than that will cause major rattle at start and your valvetrain will deafen you, not to mention you will find even the slightest oil leak on your engine, and yes, there are some.

I know this from experience with my 160k mile 190hp m20 in my e30. I also just put 15w50 in my m50 sedan last night.

[uscharalph]

I'm 90% sure I'm going to MOBIL 1 Synthetic. How about the SEAFOAM CLEANOUT?

[JonE]

I wouldn't do it, at least not until you've tried the conversion to synth, just to make sure you don't end up with a leak or leaks. I have gone with a synth blend in my 3 series m20 engine (138,000miles) to start with and if things look good, I'll go full synth next oil change. Just my 2cents.