I have a 2000 C70. For the tempertures my car is exposed to, the manual says I should use a 5w40. My problem is trying to find a synthetic 5w40. The only 5w40s that I can find locally are for a diesel. Specifically I can purchase either Rotella or Mobile 1 oils for diesels.

Both of these oilshave a rating of SL, which exceeds the SG rating my engine requires. Is there an issue in using either oil in my car?

Thanks

 

I assume you're living in an extremely frigid region.

You would be fine with synthetic 5W-30. The -40 is the weight rating for hot climate, and in your region -40 is not necessary. During winter, I would let the engine idle for at least 3 minutes before driving off. Many owner's manuals & pros alike say it is ok to start driving slowly in frigid climate, but if it were my car I would take it easy.

No, I would never use diesel oil in gasoline-powered engines. I have never heard of any report, but diesel engines have higher compression and use different fuel (sort of like jet fuel). I do not see anything but negative results.


JPN

 

Thanks. I have already used the diesel oil.

The temperature range for the car would be from 20 below in the winter to 95 in the summer. That dictated the 5w40. Some years it could be 10 degrees less or 10 degrees more but only for a day or two.

Since posting the question I have spoken with a couple mechanics and they said use it. The diesel oil is better then most gas oils and the oil is rated SL for gas exceeding what the owners manual calls for.In fact they went sofar as to saywould prefer to use the diesel motor oil, because of the turbo. They did strongly advise not to use gas motor oil in a diesel.

 

I see, as long as there's no damage to the engine. I would, however, stick to gasoline engine oil for gasoline engines. Full-synthetic oil is most suitable for the turbocharger for its chemical stability underwidely varying temp & pressure conditions. I wonder if someone else has ever used diesel oil into a gasoline engine.

I hadlived in Vermont for over 5 years and I used to use regular 5W-30 in my Accord. In summer I used to use 10W-30. You could do the sameonly if you wish, use 5W-20 in winter and switch back to 5W-30 or 10W-30/-40.


JPN

 

For what it's worth, myself and more than a few others have been using diesel oils in gas fuelled cars for some time. I have been using Shell Rimula X mineral diesel oil (Australia) in my motorcycle for 35k kms now, with no ill effects, and I run it in my Volvo as well. I had this oil in a turbocharged Toyota Supra which massively overheated (melted spark plug boots to spark plugs, would not idle) and the engine survived without even a significant drop in oil pressure.
I use teh diesel oils because they have a far superior oil additive package plus base stockto the current SM? rating, and contain anti scuff additives that are nearly completely gone in the curent rated gas oils and all for a pretty good price.
I do however, use full synthetic oils in our Mitsubishi, but only because we got teh car with such low kilometres, and it's worth it.

Regards, Andrew.

 

I don't htink I've seen a 5w-40 around here either, but a 5w-30 should work just as well for you.