Anyone using 5w40 synthetic oil?

[Russell]

I am going to try using Mobil 1 5w40 Truck and SUV oil in my 95 525i. I hear it is a very good oil as it is shear stable etc. Been using Mobil 1 0w40 with no apparent problems. Just thought I would try it. Castrol also has a 5w40 oil that looks very good. However some say it is not a true synthetic.

[632 Regal]

Truck and SUV hmm...Bimmer?

Paging Ryan

[ryan roopnarine]

I am going to try using Mobil 1 5w40 Truck and SUV oil in my 95 525i. I hear it is a very good oil as it is shear stable etc. Been using Mobil 1 0w40 with no apparent problems. Just thought I would try it. Castrol also has a 5w40 oil that looks very good. However some say it is not a true synthetic.

the 5w40 is supposed to be a "extraordinarily close" copy of delvac 1 (by mobil) which is 5w40. people that have had it analyzed say it IS NOT the same as delvac. I think its more for people that would hesitate putting a 0w oil in their "heavy duty" truck engine, and don't really have a need to put delvac (ie they don't have suv's with ford powerstrokes/international T444e's in em). if you want to try it and report back, certainly no one is going to stop you. just realise that all of the mobil 1 syn products are formulated toward the "thinner" side of the viscosity spectrum, so i doubt this is gonna help you any in your m50, any more so than the 0w40.

[Bill R.]

purposes. I wouldn't bother switching, especially on a m50 with hydraulic valve elements. I'd leave the 0w40 in.

the 5w40 is supposed to be a "extraordinarily close" copy of delvac 1 (by mobil) which is 5w40. people that have had it analyzed say it IS NOT the same as delvac. I think its more for people that would hesitate putting a 0w oil in their "heavy duty" truck engine, and don't really have a need to put delvac (ie they don't have suv's with ford powerstrokes/international T444e's in em). if you want to try it and report back, certainly no one is going to stop you. just realise that all of the mobil 1 syn products are formulated toward the "thinner" side of the viscosity spectrum, so i doubt this is gonna help you any in your m50, any more so than the 0w40.

[Russell]

Why is 0w40 better for the m50 with hydraulic valve elements?

Is it the quick pump up of 0w40 to stop/reduce valve rattle on a cold start?. That is one reson I waited until spring to try the 5w40. I never had the cold start-up rattle when I ran Mobil 1 15w50 in the summer so I thought the 5w40 would work.

purposes. I wouldn't bother switching, especially on a m50 with hydraulic valve elements. I'd leave the 0w40 in.

[Bill R.]

you won't have it with 5w40 either. However comparing the fact sheets from mobil on both i'd stick with 0w40 which has bmw llo1 approval
fact sheet 1
Fact sheet 2

Stry enough the flash point is 10C higher on 0w40 than on 5w40 also

Why is 0w40 better for the m50 with hydraulic valve elements?

Is it the quick pump up of 0w40 to stop/reduce valve rattle on a cold start?. That is one reson I waited until spring to try the 5w40. I never had the cold start-up rattle when I ran Mobil 1 15w50 in the summer so I thought the 5w40 would work.

[Russell]

I noticed that last night as well. Made me pause a bit on my decision. Anyway, I "think" I will give it a try. They sure seem to like it on the bobisthe oilguy forum.

I just do not like the way the 0w40 oil seems to get so dark at 1,000 miles. However, I have heard that is the way Mobil 1 oils act. Someone said heat activated additive package or similar.

Thanks again,

you won't have it with 5w40 either. However comparing the fact sheets from mobil on both i'd stick with 0w40 which has bmw llo1 approval
fact sheet 1
Fact sheet 2

Stry enough the flash point is 10C higher on 0w40 than on 5w40 also

[ryan roopnarine]

russell, i haven't been around bobistheoilguy.com since the roll out of the mobil 1 extended performance, about two months or so. can you give me a summary of their feelings on such things (what makes these so special, &c. &c.? i should probably search the used oil analyses board there and see for myself, but i guess i can ask you, since you are over there and all.

[Russell]

The reports are, IMO, inconclusive on the new mobil 1 oils per the oil site. However, i have not focused on the new extended life oils at all. There is some specualtion they may have changed (read lower quality) the standard Mobil 1 line to seperate it from the extended life oils. That is all I really know at this point

russell, i haven't been around bobistheoilguy.com since the roll out of the mobil 1 extended performance, about two months or so. can you give me a summary of their feelings on such things (what makes these so special, &c. &c.? i should probably search the used oil analyses board there and see for myself, but i guess i can ask you, since you are over there and all.

[Gene in NC]

So what is the recomended replacement for M 15/50?