I think my 3.4L asks for 5W-30. I'm thinkining of going to mobile 1 synthetic. Should I stick with 5W for Colorado heat and mountain/city driving? Would 10W be preferable?
Thoughts?
thanks

 

i use mobile 1 synthetic in all my cars. usually put in 10w-30 in the summer and this winter there was a big sale on 0w-30 so i bought some of that. i'll be doing that every winter from now on. i can't tell you how much easier the truck start after sitting out all night in 0 degree temps. it's great. remeber with sae oil weights, the W number is for "W"inter, i.e. when the oil is cold, and the other number is the weight at operating temperature. since they are both 30 weight when warm there really should be no trouble running that in the summer, but out of habit i'll probably go back to 10w-30 in the summer.

 

5W30 year round is all you need.

 

if that's not enough, i'd switch to 10w40. i'm a firm believer that you need to pick what oil is best for the driving conditions. the owners manuals used to have a chart with viscosity ranges for the ambient temperatures. i can't see 5w30 being too great climbing a mountain pass in the summer heat

 

My book calls for 5w 30 in my 01, 2.7. Keep in mind that once it's warm you have the 30 weight protection no matter what the first number is.
I drive mountains every day year rouund and have never had a problem with myn Mobile1 syn 5 w 30 and I have 71,000 already

 

It doesnt really get too cold down here in SC but I run 10w30 mobil1, I will try to find it again but I found a website to an automotive research college that had many different variables with different brands of oil, Amsoil and Mobil 1 came out on top. In the winter it's best to run a lower number in W (which means winter, not weight) because it's not as thick. In the summer, heat causes the oil to become thinner so the thicker it is the better.

 

Thanks for the info guys, It can get up to 100 in the desert where I go in the summer, maybe I'll go with 10W for the summer and back to 5W in the winter. Incidentally, should I throw some seafoam in the crankcase and drive a little before I go synthetic?

 

Always remember you mileage, as engines wear down gaps get larger and a thicker oil has less chance to get through. I have steped my oil up a notch after the first 100K and then again at 175K or so. I have had 2 F250 460's last 250K so far. 22RE last 240K and my 96 V6 Runner is at 155K and 0 problems so something must be ok. Watch the synthetics. I had a Prelude that was running fine at 110K, changed to synthetic and wouldn'y stop smoking from then untill the day I sold it. Toyota Example

Winter & Summer below 100K 5-W30.

Winter above 100k-175k 5-w30
Summer above 100K-175k 10-w30

Winter 175K+ 10-w30
Summer 175k+ 10-w40

 

Grade/weight of oil – Viscosity (flowability) is how to measure the shear strength of a thin layer of oil. A bearing works by using a thin layer of oil not by the oil pressure generated by the pump. If you use too high of a weight oil the layer will not form fully or may not get into the bearing at all. If you use too low a weight the layer will not give the bearing the proper protection. Bottom line, make sure you stay within the manufactures recommended ranges.

Koz

 

You realize that a place like Breckenridge rarely sees summer temps over 80F. Most often between 65F and 80F. As you hit the passes above, the temps go down.

Obviously Denver and GJ will heat up into the 90s but they're not exactly that hilly.

THere's probably another discussion here about the pour point of mobile 1 synthetic 5w30 v. 10w30 or even 10w40.

Personally (as a colorado driver; but again my toyota is only getting broken in at 90k miles) mobile 1 5w30 should be fine year round. 10w30 in summer is popular too. Unless you're living in the high country I wouldn't worry about 0w in winter.

 

an interesting factoid -- straight 30 weight at operating temp will protect better than any 5w30 or 10w30. more pure oil, less polymer viscosity modifiers. problem there is that it's a lot thicker than those when cold. generally you want to pick the narrowest viscosity gap you can, as this will contain more oil and less additives, e.g. a 10w30 rather than 5w30 if you can get away with it.

i'm running 15w40 and like it a lot, though i think it might be a little thick for the winter. on some really cold days(20* or so) it caused my oil pump to make a bit of a whine like a geardrive on a V8 if i tried to hit the gas within about 30 seconds of starting. i'll probably give amsoil 10w40 a shot and see how it works.