Summer and Winter Oil???????

[bfg9000d]

Currently I'm driving a 2004 toyota camry. I'm using what the manual says which is 5w 30. I'm really to affraid to go any thinner then that. During the summer I was running
10w 40 because it gets up to like 104 to 105 out here during the summer. My main concern during the summer should I switch back to something like 10w 30. I dont mind a cut in fuel economy if it means I'm getting added protection. The last thing I need right now is a siezed up engine during the summer.

[GasSavers_BIBI]

For winter, stay with the 5w30. Also, synthetic oil will give you better start in cold condition.

[trollbait]

If you are worried about damaging the engine, stick with recommended oil. The oil runs at temperatures greater than 105. So their is no need to use a different operating temp oil between seasons. The 40 weight may even get hotter than the 30. Being slower flowing it stays in the hot spots longer. Thicker oils can also put more strain on the pump. That can be increased by the heavier cold weight. The difference in actual viscosity between the 5w and 10w can be greater than the difference between 30 and 40, at their respected temperatures.

Are 10w-40 oils certified by the API anymore?

[GasSavers_SD26]

I'm sure they have API certifications, but I wouldn't think they are SH or whatever they are up to now.

[kamesama980]

just use what the manual says. the engine tries very very hard to maintain a constant operating temperature no matter what the ambient temperature is. in something new like an 06 and well designed as a toyota, it will succeed unless you're going outside the range of temperatures we can survive in. plus, the oil will chemically break down from overheating long before it's too thin to lubricate.

[yi5hedr3]

Mobile-1 5w-30 year round!! Make it so!

[trollbait]

Originally Posted by SD26

I'm sure they have API certifications, but I wouldn't think they are SH or whatever they are up to now.

I just don't remember seeing the API star on any bottle certifying it for use in gasoline vehicles. Which can be a problem if something goes bad under the car's warranty. In which case, the oil could exceed the specifications, but you'll have to prove it because the bottle didn't came with that star.
I don't Amsoil has that star either.

[kamesama980]

Amsoil adds a few things to the oil that violate the API guidelines. basically, they make it better, API (like everything in america nowadays) is all about economy and anti-pollution.

nevertheless, using non API oil, even if it is better, will void warranties. generally it's best to use API certified oil though