I have two BMWs with M30B35 sixes. This is 60s era technology but they are good engines. Both have high mileage and both run extremely well. It's time to use my Mobil 1 rebate coupon in a couple of weeks and, since you know Mobil 1 well, I will ask you to choose an oil for me. Being on BITOG has changed me from a 20w50 for everything guy to one who likes to experiment. I am running M1 0w40 in one car and like the way it performs but the back of my mind says it's too light for this engine. Probably a 20w50 mindset holdover. Should I keep using 0w40 or would 5w40 TDT or 10w40HM be more appropriate?
Doug Hillary, question
- Thread starter Ken E.
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Once you run a 40 instead of a 50, the left number( winter/cold number) is irrelevant. Heck between 0W and 5W down around most normal temps is really close. 10W is not far off. Remember the higher number is actually the operating temp number and the left number even (even if 0W) at 70 is many time thicker. Run either the 5W or 0W and you will be fine. Remember also back then the lousy Group I oils would break down quite a bit and that was factored in to the recommendation. Modern oil will not.
Run with confidence. If you race and want to goto 15W-50 watch your oil pressure and let that be your guide. That being said if you have a gage and watch it anyway, about 10 Psi for 1000 RPM at redline.
Run with confidence. If you race and want to goto 15W-50 watch your oil pressure and let that be your guide. That being said if you have a gage and watch it anyway, about 10 Psi for 1000 RPM at redline.
Check out mye28.com, probably the best forum for BMW M30 specific issues.
Most will still tell you to stick with 20W-50, with sound reasoning to back up their claims. I'm putting in a rebuilt M30B35 (from an '89 535i) into an 1985 E23. I'll be using 20W-50.
Most will still tell you to stick with 20W-50, with sound reasoning to back up their claims. I'm putting in a rebuilt M30B35 (from an '89 535i) into an 1985 E23. I'll be using 20W-50.
Is Doug still around these days ???
Doug is still around but he was getting ready to take a trip to Europe to visit the Porsche and MB factories. Said he would be checking in from time to time while he was there. Not sure when he was going but I think it was sometime this month.
Ken E, if your BMW is not consuming the 0W-40, I would stick with it. That is a very good oil.
Ken E, if your BMW is not consuming the 0W-40, I would stick with it. That is a very good oil.
Hi,
Ken E - Sorry for my slow response - you have good replies anyway. I am at sea near Indonesia en-route to Europe
Either lubricant will do the job very - M1 0W-40 or TDT 5W-40 depending on the annual ambient spread of course
In older technology BMW engines TDT is a very good performer
Ken E - Sorry for my slow response - you have good replies anyway. I am at sea near Indonesia en-route to Europe
Either lubricant will do the job very - M1 0W-40 or TDT 5W-40 depending on the annual ambient spread of course
In older technology BMW engines TDT is a very good performer
Thanks Doug, I did get some good responses. That's what BITOG is all about. Enjoy your trip.
I tried 15w50 on one of my BMWs and the car seemed sluggish. I'm sure the protection is there but,based on that experience, I'd rather not use a 50 wt. oil. I think I will go to the 5w40 TDT in the 535 that is due for an oil change (wife's automatic '90) and see how it does. Thanks.
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