Switched to synthetic oil and now.....

[BlueOx12]

Ok guys i recently switched my oil from 15w40 rotella to 5w40 synthetic rotella. And i have noticed on my pmt that my oil temp is running noticably hotter now. Now what i was wondering is is this because i switched oils?? or does it sound like somthing of a bigger problem? with the reg. oil my oil temp was usually running like anywhere from 180 to 190 with normal to hard driving and it never went over 200 until i was towning my 28ft 5th wheel. Now on normal driving running anywhere from 75 to 80 mph my oil temp is consisantly reaching the high 190s and more often than not its going over 200?? Anybody have any input on my current situation/dilema??

Thanks,
kevin.

[94f250]

how many miles have you put on the truck with the synthetic oil in it?

[BlueOx12]

maybe 300 to 500 miles if that...

[Baddestt]

Next time try Amsoil AME 15w40 diesel synthetic.

[bismic]

There is no way it is the oil. If anything, you may have your oil cooler beginning to plug up on the coolant side. Definitely keep an eye on it. Also - you should never see more than a 15 *F difference bewteen EOT and ECT.

[BlueOx12]

yea thats what i was thinking that my oil cooler was messing up.....is there anyway to check this in further depth???

[smokersteve]

5w40 is thinner than 15w40. That’s why 5w40 is used for colder climates than warmer. It’s stated in the manual. The thinner oil produces better mileage cuz of the easer flow. But this also presents a lack of lubrication because it is thinner than 15w40.

[bismic]

Originally Posted by smokersteve

5w40 is thinner than 15w40.

Not at the operating temperatures of the engine. They provide the same protection in this temperature range. The 5W40 provides extra protection at the ambient (environment) temperatures since it will flow better at cold temperatures. The oil manufacturers obtain this wider range of performance with synthetic base stock AND VI additives (Viscosity Improvement). Ford did not recommend the 5W40 as a "year round" oil because at the time, they did not sell a 5W40 oil.

[Baddestt]

Originally Posted by bismic

Not at the operating temperatures of the engine. They provide the same protection in this temperature range. The 5W40 provides extra protection at the ambient (environment) temperatures since it will flow better at cold temperatures. The oil manufacturers obtain this wider range of performance with synthetic base stock AND VI additives (Viscosity Improvement). Ford did not recommend the 5W40 as a "year round" oil because at the time, they did not sell a 5W40 oil.

Very well stated

[pete37922]

i use my Amsoil 5w-40 all year long and no probs !!!