Originally Posted By: nathancarter
Originally Posted By: KLowD9x
Holy [censored]! You have been going 7500 miles between services with conventional in the sump!?
Yes; that's what the Volvo manual recommends.
The Volvo manual also recommends 5w-30 conventional, except for "Extreme engine operation" for which it recommends 10w-30 synthetic.
And the BMW manual recommends 15,000 mile intervals on BMW 5w-30 synthetic, which apparently performs similarly to GC 5w-30 and M1 0w-40. (I do 7500 mile OCI)
And they both say that the transmission & differential fluids are "lifetime fill." (I've already changed 'em in both)
So, what do I believe?
People say "Use 5w-30 because that's what the manual recommends" then in the next breath say "The manual says 7500 miles? Don't believe everything you read!"
It smelled pretty burnt at the last change, but can you really tell anything by the smell coming out of the drain hole? I thought nothing of it, but for 12 years I drove an old diesel M-B 240D, so maybe the nose doesn't knows.
sigh.
This leads back to the question:
Fuel economy and turbo response notwithstanding, would M1 0w-30 really offer better protection than M1 0w-40?
The BMW, at 101k, is well out of warranty, but the Volvo still has CPO warranty to 100k... if I can find a legitimate dealer to do the CPO work, but that's a different rant.
I think the 0w40 would offer greater protection. IIRC, doesn't it have higher levels of ZDDP?
But, don't listen to the manual when it comes to servicing. I have been working on these cars for a long time and I can honestly tell you that conventional in a Volvo for 7500 miles is a very bad idea. Same for the "lifetime" ATF and "lifetime" coolant.
Put 0w40 in it and call it a day. You have nothing to worry about because I have put some SERIOUS mileage on my 850 (same engine, just higher compression and hydraulic lifters instead of the solid ones you have) with M1 0w40 and it runs like new!
