Originally Posted by Whammo
I have seen a lot of people recommend running a 5w30 instead of a 5w20 in summertime. As far as I know, the engine operating temp isn't going to be higher in the summer. If the manual says 5w20 is fine year round, why mess with it?
Actually its quite sane to use a higher weight oil operating your vehicle in hot weather. Of course the oil operating temperature is going to be higher in the summer. In some cases depending on vehicle and use much higher. Oil temperatures are not controlled by a radiator and thermostat like the coolant is except in cases of some vehicles outfitted for heavy duty towing.
Its silly to think that oils temperatures will be the same in my state where temps have been a constant 90 to 100 degrees for weeks now compared to cooler areas of the country. In fact, since I no longer live in a colder state, its silly for me to use anything but a 5w30 year round. I do not need a 5w20 like someone upstate NY with wintertime temps in the 0 to 40 degree range.
The manufacturer recommendation of 5w20 is a blanket recommendation, average if you will, for the entire continent, you can fine tune that to your climate. 5w20 oil is of no use to me when I start my truck up in 90 degree heat. In fact a straight 30 would be fine.
Furthermore the 5w20 its for fleet fuel mileage in mind, for the best EPA results they can get.
If you stick with your manual you will be fine but there is a good reason to fine tune your weight oil to your area, most people are not capable of this but its not rocket science.
If makes FAR MORE sense to fine tune your weight oil then select one brand over another brand if they meet the same API. Now that is something that makes no sense, choosing one oil brand over the other when they meet the same API. Conventional and synthetic ...
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