Oil weight?!

[JonnyOg]

Tired of searching and finding tons of different answers, what oil weight should I use?
B.C. climate, similar to washington. Running 15-40 rotella and my car sounds like shiiiet on startup. What are you guys running?

[jntar]

Started off running 10-40 Mobil 1 high mileage, but I found that 5-40 Castrol Edge (BMW blend) was cheaper and worked just as well.

When you say sounds like shit do you mean noisy? Rattle sound? Might be time to check the timing chain/guides/gears/tensioner.

[JonnyOg]

Yea just changed the tensioner 5 minutes ago actually. Yea sounded like a diesel on startup. I'll probably just go with a 10-40 I guess.

[Tisoc]

Diesel? No bueno, your timing is off. Have you checked your cam gears? Other chain components may be toast as well.

[nickmcc92]

I use shell rotella t6 5w-40 here in SoCal and my car sounds the same on start up

[JonnyOg]

Diesel? No bueno, your timing is off. Have you checked your cam gears? Other chain components may be toast as well.

After the new tensioner it has stopped this noise.

[nickmcc92]

Was it a clacking type of noise on start up?
Did it get rid of the Diesel engine?

[Threehz]

10-30 (or 10-40) Castrol GTX is the what your M42 craves.

[Nick_S]

I always used 10w-40 but last time tried 20w-50. On chilly mornings it's definitely louder and get a lot more valve tick till it warms up. Will be switching back to 10w-40 soon.

[roguetoaster]

My M42 seems to be happiest with 10w-40, in either Castrol Sytec or Rotella T. I have noted that in plain appearance those both seem to have heavier static viscosity vs. other synthetic 10w-40s.

[M3Philipp]

10w40 for the M42.
If you live in a hot area somewhere on this planet, may even use 10w50, 20w50, 10w60.

[kwill22]

I use 0w-40. Works fine and 5w-40 worked good also. No problems for me

But you're are in a completely different climate than me

[sfinsf]

210k on clock, new tensioner, running 20w-50 and peeps have said it's the quietest M42 they've heard. Also seems to disappear less. when I was trying different oils, any of the 10's would disappear faster, never tried anything less than 10w.
I was adding 1/2 quart every wk or so with regular driving with the 20-50 it's more like every 2wks.
oh and these were all dino's

[irish44j]

I'm running Rotella T6 5w40 and mine isn't noisy on startup (well, it is because I have solid motor mounts, but the ENGINE itself isn't noisy), and smooth as an M42 can be when moving. I also don't lose any oil at all between changes.

[goinstrong]

10/40 for sure...Castrol GTX is always a good choice!