Newer diesel oils in older gas vehicle

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Hello everyone, I've been reading these forums for several months and figured I'd sign up and ask a burning question.

So background, I have a 1987 BMW e28 (m30 engine) that's seen 20w50 oil for most of my ownership which has primarily been Castrol. I've used Mobil 15w50 before and had people tell me it wasn't necessary for my engine, well after some research I've found that my engine needs a little higher zinc content than most engines I already know that Mobil has good zinc levels but I can't find any info on castrol so I have come to the conclusion of trying out some diesel oils after reading about people using them in there non-diesel vehicles. I went to my local Walmart and picked up some Rotella T4 that was still sm rated (there were ck4 bottles mixed in the stock) also some Castrol diesel truck 15w40 that was on sale for 9.80, why not right?

So my question, is there anything to be worried about in using with of these oils in an older engine like mine that likes a lot of zinc? I don't drive like a grandma either so that's why I'm like paranoid about finding cost effective oil to keep her happy.
 
Most engines after they have seen over 300k miles like yours don't really need super high zinc oils.
I think you should stay with Mobil 1 15W-50, it sill has around 1100-1200ppm zddp which is more than enough for your bimmer.
 
Welcome to the forum.
welcome2.gif


Very important question: What does your owners manual say? Judging by your oil preferences, something thicker I am assuming?

After a steady diet of 20w50, I don't see a switch to 15w40 being an issue at all. You certainly live in the right climate and the price seems right too.
 
There is diesel only oil.. I assume you are talking about "mixed fleet" oil with the dual ratings?
 
Originally Posted By: Rand
There is diesel only oil.. I assume you are talking about "mixed fleet" oil with the dual ratings?


Yes, the shell is SM and Castrol SN. I've been searching all over for zinc/phosphorus information on the two oils since I've read that Rotella in general has lowered zinc levels, to what degree I do not know. If it still has at least 1100ppm that should be good with me.
 
Swing by the used oil analysis - diesel here and check out the reports. Nearly all of them contain the info you're looking for ( zinc levels etc ) and maybe that'll help you make your decision on what you want to run.
 
Originally Posted By: double vanos
Swing by the used oil analysis - diesel here and check out the reports. Nearly all of them contain the info you're looking for ( zinc levels etc ) and maybe that'll help you make your decision on what you want to run.


Ah yes, I didn't think to look there for some reason...thank you!
 
Originally Posted By: Ohle_Manezzini
Try to buy on that has also A3 B4 specs, more important than SM or SN in your case.


I know the Mobil 15w50 does, but it's probably the only thing I can find locally in the proper weights. But may I ask why?
 
Originally Posted By: Samrsnow
Yes, the shell is SM and Castrol SN. I've been searching all over for zinc/phosphorus information on the two oils since I've read that Rotella in general has lowered zinc levels, to what degree I do not know. If it still has at least 1100ppm that should be good with me.

If you're sticking to a 40 grade HDEO, you should do fine. Even if you were to go to a 30 grade HDEO, note that there is more to anti-wear than old school ZDDP.

To expand on Ohle's point, he points out something valid, but it will be confusing in the North American marketplace. Where you are, you can get a good 5w-40 or 0w-40 (or 5w-30 or 0w-30) A3/B4 lubricant, which will do just fine, and which you can probably get for a sensible price.

In some markets, one can get a 15w-40 with A3/B4. Finding that here isn't going to be easy, and will probably be a fool's errand. Any 15w-40 you find with ACEA specifications in North American will almost certainly show E7, E9.

The SM or SN is good to look for, not for a specific performance level when buying an HDEO, but just to make sure you're not buying something meant for a DD 2 stroke.
wink.gif
 
Originally Posted By: Samrsnow
Originally Posted By: Ohle_Manezzini
Try to buy on that has also A3 B4 specs, more important than SM or SN in your case.


I know the Mobil 15w50 does, but it's probably the only thing I can find locally in the proper weights. But may I ask why?


They're designed with longer drain interval in mind, so it has to be stout, for shearing and mostly use superior add pack.
 
Thanks guys, I put in the shell oil along with two Delo 400le bottles since I can get them cheap where I work and a Wix filter.

Honestly I would not put 0w40 in this car unless it was like freezing temperatures for the next few months, but I live in Louisiana so I'll stick with thicker oils because that's what the old straight 6 engines call for in hot climates.
 
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Originally Posted By: Samrsnow
Thanks guys, I put in the shell oil along with two Delo 400le bottles since I can get them cheap where I work and a Wix filter.

Honestly I would not put 0w40 in this car unless it was like freezing temperatures for the next few months, but I live in Louisiana so I'll stick with thicker oils because that's what the old straight 6 engines call for in hot climates.


You mixed Rotella and Delo?
 
Originally Posted By: BobFout
Originally Posted By: Samrsnow
Thanks guys, I put in the shell oil along with two Delo 400le bottles since I can get them cheap where I work and a Wix filter.

Honestly I would not put 0w40 in this car unless it was like freezing temperatures for the next few months, but I live in Louisiana so I'll stick with thicker oils because that's what the old straight 6 engines call for in hot climates.


You mixed Rotella and Delo?


Yeah, is that a no no? I couldn't find more than one quart of Rotella t4 when I was in the store so I said screw it, I can get more oil at work at cost.
 
Originally Posted By: Samrsnow
Yeah, is that a no no? I couldn't find more than one quart of Rotella t4 when I was in the store so I said screw it, I can get more oil at work at cost.


Nothing will blow up...
 
Originally Posted By: Samrsnow
Hello everyone, I've been reading these forums for several months and figured I'd sign up and ask a burning question.

So background, I have a 1987 BMW e28 (m30 engine) that's seen 20w50 oil for most of my ownership which has primarily been Castrol. I've used Mobil 15w50 before and had people tell me it wasn't necessary for my engine, well after some research I've found that my engine needs a little higher zinc content than most engines I already know that Mobil has good zinc levels but I can't find any info on castrol so I have come to the conclusion of trying out some diesel oils after reading about people using them in there non-diesel vehicles. I went to my local Walmart and picked up some Rotella T4 that was still sm rated (there were ck4 bottles mixed in the stock) also some Castrol diesel truck 15w40 that was on sale for 9.80, why not right?

So my question, is there anything to be worried about in using with of these oils in an older engine like mine that likes a lot of zinc? I don't drive like a grandma either so that's why I'm like paranoid about finding cost effective oil to keep her happy.


Nothing to worry about CJ4/SM is fine.
Also as someone else mentioned the 15/50 Mobile 1 is fine too.
and honestly any 20/50 but yes it would be cool to see if you can find one with higher zinc.

With the new CK4 oils that are coming out, some are comming out without a "S" rating and I think that is because of the zinc/Phos limit is higher BUT you would need to confirm and if proven true you may be fine using a CK4 without the "S".
Take my comment about the CK4 with a grain of salt as I have no idea what I am talking about because I know nothing for fact but you may consider looking into it. :eek:)

Ps. Mystik makes a CJ/SM oil in the 15/50 with high everything, there is a VOA in here on it a few pages back. Mystik JT8 15/50.
Can be bought at Rural King cheap, shipped right to your door.
Made by Citgo.
 
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