I noticed Costco has 15-40 Castrol recomended for Diesel Engines. I like the weight for my 92 300e.....any concerns I should have ???

I think you'll find that any oil rated for diesel engines is more than adequate for gasoline counterparts. If you like the oil go ahead and use it.

As LarryB says..."Change it hot and change it often!"

Good luck!

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Daily Driver: 02 E430 4MATIC
In the family: '03 E500 // '04 ML500 // 64 220SE

Diesel oil is made to help suspend soot. While that won't hurt in itself, every additive package is a compromise. I'm sure that it's rated for S* service as well as C*, but it's probably not ideal.

If you do a search you will find this topic has been discussed many times before. Don't let the diesel rating confuse you, and no, the additive package in that oil is not a compromise for our gas engines. This oil is ideally suited for our engine. While we may not need soot control, that aspect of the oil gives it superior particulate suspension qualities. The petroleum manufacturers have listed it for years as recommended for hard working European cars, including BMW and Mercedes "GAS" engines. It is even on the approved list from Mercedes for your vintage engine. Oil additives are dramatically different for newer engines and don't give the best wear protection for engines not designed for them. Folks in the know about lubricants have testified many times on other boards about how good this oil is for 124 gas engines. If you don't live in a climate where you need very low viscosity in the winter, 15W40 is perhaps the best range for our cars. You can get it in regular Dino, synthetic blend and full synthetic - your choice - but sometimes have to search or special order. I am currently using the blend version from Castrol - found on the shelf at Kmart. Oil choice is one of the hot buttons. We all have opinions and favorites.
OliverB

I have been using 'diesel' oil in all my gassers including a 11K rpm'ed motorcycle that runs it's clutch and tranny in the same oil as the engine.

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82 300D....went to MB heaven
90 350 SDL....excercising con rods

I run 15W40 in my walk behind mower haha, it is just so cheap that we buy it in bulk so we run it in everything not just diesels. WE have not had a problem so far and have done it on lots of equipment for a long time, I agree it might not technically be ideal... but it seems to be fine for me.

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1976 300D 115 Blue Grey exterior 95K miles


2004 Dodge Ram 2500 Cummins Silver exterior 5"stacks etc...