my only issue is that this is for a friend not as crazy about oil as I. SO in a way, I think that stating and sticking with one viscosity would be best.
Today it is 14F, so its obviously pushing what a 15w-40 could do. Rarely does it go to 100F here, and the car isnt going to be heavily stressed. Im starting th think for simplicity that a synthetic 10w-30 is the best choice. But that leaves me with M1 which is a light 30 weight oil, maybe not best for euro engines??
As much as I like the idea of a 15w-40, Im thinking it may be smarter to go with something that allows the summer and winter protection. M1 10w-30 is a good stable oil, and although it is a thin 30 weight oil, it will stay tough at high temperatures, and give protection at lower temperatures than the 15w- plus, its an 'authorized' weight. That said, Im happy with using rotella syn 5w-40 in my BMW, which specs 15w-40 or 50 for most conditions. But, at the same time, BMW authorizes 'special oils' or synthetics which will protect through the whole range (though apparently Volvo has authorized an older flavor of M1 for their cars, in the 10w-30 grade).
Its just that Im not knowledgable enough about volvos to say for certain that Id go with a 5w-40, or say, GC in 0w-30, both of which would be my main choices, I guess. But I dont want to push the suggested rrequirements too much without good justification, since its not my car, and wont be constantly verified with UOA.
Why cant 10w-30 HDEOs be more available? It would solve so many problems!
Does anyone forsee an issue with alternating castrol 15w-40 and then GTX 10w-30? It may be good for a summer/winter alternation? I think Id rather see something like that than delo 400/M1 10w-30 changes... It keeps a standard brand, the correct weights, and can be changed every 6 months/5000 miles per the severe manual schedule without worry, and the correct viscosity could be chosen depending on the weather in the upcoming months. The only problem there, once again, is that its not synthetic, which would be preferable.
Maybe Im thinking too much about this... Maybe I should just suggest delo 400 15w-40 which has decent cold performance, or just spec M1 10w30, so its orrect for 99% of all the conditions his car will see. After all, my father's 94 previa, with 2.4L N/A 4cyl engine is probably specced for 15w-40 in most conditions int he rest of the world, but we use M1 10w-30 with great success, to the extent of 8ppm Fe in 13K miles, and negligible Cu, Pb! Maybe it would be a good suggestion??? Maybe all the information on this site is making this too tough!
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Thanks for your help!
JMH
[ January 19, 2005, 07:54 AM: Message edited by: JHZR2 ]