Which oil to use

[smokeyyank]

First, yes I have searched and I know this topic has been beaten to death, but I still can't find a good answer as I think it all depends. So my question is which oil should I use for MY car? I just purchased it and need to change the oil. I don't know what the PO used, but I can see a purrolator oil filter so my guess is whatever Midas put in it. I live in Colorado, currently has about 150k on the engine, car is only going to be driven in nice weather (my guess on temps would be between 40-100), this isn't my daily so it may sit for a while at a time and I have a lead foot. I'm leaning towards Castrol 10w40 non syn. Thoughts?

Thanks

[wannaBMthree]

20w-50, vr1

[efficient]

Vr1 kills cats. Says on the bottle

[smokeyyank]

So I know the VR1 says it is bad for cats, but since this isn't a DD and I'll probably change the oil twice a year would that really matter?

[gwb72tii]

how about what the owner's manual says?

[smokeyyank]

gwb72tii, I agree, and I think it's just regular 20w50 and then changes for winter, but what I've been reading is that since oil has changed so much over the years along with its characteristics what was recommended back then may not be the best now. Hence my conflicting info about which oil I should use for my specific application.

[estoguy]

I've been using Castrol Edge 5w50 for the past couple of years. Seems to be doing the trick.

[ELVA164]

As mentioned, the manual is outdated and inaccurate. In Denver you could use Mobil 1 0W-40 year round. I've done so for a year and a half here and it's worked great. Mobil 1 15W-50 would work well too. Both have sufficient ZDDP and a good track record. For the record, I contacted Mobil and BMW separately about this and they each recommended the 0W-40.

[dnguyen1963]

I have been running Farm and Fleet diesel oil 15W40 ($8 a gal) for years...

[jlevie]

You want an oil with a high ZDDP content because of the flat/sliding rocker arms. There are a number of pure race oils with satisfactory ZDDP levels, but they aren't intended to be in the engine as long as a more conventional oil with detergents.

A couple of oils that are suitable and have sufficient ZDDP to protect the cam and rockers include Amsoil Z-Rod 5w50 and Shell Rotella T. The best oil filter is a Mobil one and second best is OE or Mann.

[smokeyyank]

Alright thanks for all the info. I had been reading about an oil that has enough ZDDP and while I'm not opposed to a race oil just want to make sure I'm putting in what it needs.

[jeffnhiscars]

You should be opposed to a race oil for off track use. They are intended for far more frequent changes and sever use than "street oils"... Not to mention they typically cost quite a bit more than even M1.

I can't believe this ismstil being talked about

[AndrewBird]

Nothing wrong with running race oils in a street car, you just have to be aware that it needs to be changed more. The only reason to run them is the high levels of ZDDP (zinc), which is what clogs up cats. This is why modern oil has low ZDDP levels.

You can also buy ZDDP additive and then use whatever oil you want.

I prefer 20W-50 VR1, except in the winter when it is consistently near or below freezing. Then I run 10w-30. I usually buy it on sale at Autozone for $3 a quart.

[smokeyyank]

Went with Mobil 1 0W-40. Thanks for the info!