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Re: Straight weight oil? (archive)

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Posted by Brian K on August 31, 1999 at 15:24:20:

In Reply to: Straight weight oil? posted by demet on August 30, 1999 at 11:04:24:

Opinions on oils are kind of like opinions on religion: lots of people have differing opinions, all of which are difficult or impossible for the average consumer/car owner to test or verify. Like religion, opinions on oil are based a lot on "feeling" and faith, and little on verifiable fact.

That being said, I do seem to recall that there was great debate about the value of multiweights when they first came out. The "oldtimers" were concerned about the viscosity enhancers, etc. But, it seems that in the decades since its introduction, the benefits of multiweight over straightweight have been pretty much universally accepted. I doubt that you will find a car manufacturer in the world that fills its cars' crankcases with straightweight, or recommends the use of straightweight over multiweight.

I will personally continue to use the multiweight oil in the appropriate range as set forth in my owner's manual.

However, it does seem possible (although not likely to me) that a straightweight may for some reason help solve some problems in a high mileage, worn engine. If it is working for you, I'd say stick with it!

: The use of sraight weight oil does'nt seem right. I'm no expert at this but my question is how can you be assured that you are getting proper startup lubrication if your using a 40W oil? In the sun belt this may not be a factor but if you live anywhere where the temp drops appreciably I think a multi-weight oil like 20W50 would offer better protection. After all is the idea that most engine wear happens during starup and warmup a false one? Anybody with sufficient knowledge in this?

: Just curious.
: demet
: 87 528e

: : Took my 533i with 190K in for some rear end work recently, and mentioned to my mechanic that she (the car) was burning a fair amount of oil (~1 qt every 700 miles, more toward end of oil change cycle of 3000 miles) and that I suspected valve stem seals as the culprit. We discussed the history of the problem and the engine work that others had had done before we bought it, and he opined that the 10-40W Castrol we had been using was a lousy oil to use. In fact, he said ANY 10=40W oil was just no good for it. Now that was the first time I'd ever heard anybody badmouthing that particular range of multi-visc's.

: : He said 20-50W or 10-30W would be passable,but what he recommended as first step was using single weight oil: 40W in summer, 30W in winter (we live in western virginia). So last month I went to 40W Castrol. Its been 500 miles and no oil consumption yet. Am keeping close eye on the stick though, as more miles get put on this oil.

: : Has anybody else ever heard of this admonition to stay away from 10-40W?

: : Thanks.
: : Joker

: : : quick survey of what oil all of you run in the summer and winter. ANY comments are helpful.

: : : i have my own ideas about oil but i want to know what is out there. currently i am running Valvoline 20W-50 in the summer, and i ran that last winter, but i am thinking of going to a 10W-40 or 15W-40 for this winter. i always change every 3000-3500 miles.

: : : also, i was wondering if anyone knows about the detergent properties of Valvoline All climate. i run it in both my bimmers, and they seem to like it. i have a 79 320i with 260,000 (!) and my 85 535i has 160,000. i want to keep the thicker oil in the 320, but in the 535, it's been very well maintained all it's life, and the engine is nearly factory tight. oil comes out nearly clear, but the engine is pretty clean. do you think the Valvoline is high enough or too high in the detergent factor?

: : : another random question: what is the largest size TRX 390 tire available, and does it come in all speed ratings?

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