[Aris]

to use when temperatures go above 100F for a long time? Mobil1 5w30 or 10w30 are good to temperatures up to 100 F according to user's manual. So can i go with 15w50 for a Celica Gt-s ? Anyone that knows please tell me

 

[J2KGTS6]

i'm not sure exactly about the different weights.. i've been using 5w30 Redline oil, and my car has actually run one notch cooler then before. So maybe check out some redline.

 

[GT-S Celica]

yup i'm using 5w30 redline synthetic and my car is running cooler. it used to take me around 2.5 mins to warm up my car in the morning, but now it takes me over 3 mins.

 

[00 scrub]

heavier weight oil will be better for higher temps. You might want to ask this question over on http://theoildrop.server101.com/cgi/ultimatebb.cgi
The people here have alot of info that would be useful for you.

 

[Griffin]

going to 15W50 in a car with VVTi or VVTLi is not a very good idea.

 

[SlasherX]

heavier weight will help, but i'd personally focus more on your coolant levels and fuel octane in a warmer climate, provided you stick to a quality synthetic like mobil 1.