Posted by Gordon Maney on Monday, October 08, 2007 at 14:43:00 :
In Reply to: Does cheaper quality oil give you lower oil pressure reading posted by Jesse on Sunday, October 07, 2007 at 19:34:48 :
The API [American Petroleum Institute] defines service classifications and the SAE [Society of Automotive Engineers] defines viscosity ratings.
You mention cheap oil, yet say nothing about what viscosities you might be comparing, and whether they are straight weight or multi-viscosity, or what API service classification. You should find that all oils sold at your typical consumer outlet will meet current API requirements as stated by new car manufacturers. If you buy a quart of non detergent, that is suitable only for oiling the exercise wheel in your hamster cage. Don’t use it in your old truck.
Additive packages can vary in the amount of viscosity index improver they contain. Viscosity index is a measure of the resistance to viscosity change resulting from a change in temperature. Viscosity index improver is an additive that improves the viscosity index, just as it says, meaning that it causes the oil to be more resistant to viscosity as a result of change in temperature.
Pour point is the lowest temperature at which an oil will flow. Synthetics have better, lower, pour points and have flatter viscosity indexes.
Having said all of that, however, and this will be an unpopular view in this group, I suspect, but....if you are comparing the same viscosities and API ratings, then the answer to your subject questions is, no.
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