Read this and it may change your mind on using 5W20

http://www.synlube.com/sae5w-20.htm

got me to make the change over to 5W30.

 

I suppose I could tell the stealership to put in 5w-30 instead and hope they will instead of saying they will and but actually won't. At work we put 5w-30 in all of our equipment and during the winter when it gets cold the oil thickens up almost to much, almost like gel,and starts causing all kinds of problems. But then again that is on diesel engines.

 

I workin a lube shop and the reason that they have gone to a 5w20 is that manufactures have to meet certain regulations with there motors . 5w20 is an energy efficiant oil that helps the company get a better mpg rating . will 5w30 or even 10w30 hurt ? no but that was the oil they used to get there mpg rateing And if you live in alaska like 02wrangler the 5w20 gets to the op of the motor faster than your heavier oils just my 2cents

 

My 07 cap for the HO engine says 5W-30. The dealer says we only use 5W-20. No way! I use 10W-30 during the cooler months and 10W-40 during the summer. That 5W-20 is like Wesson veggie oil. I ran 20W-50 in my 5.2 95 DAK and no problems with that engine for over a 167k.

 

Great read mahadigus!

I've been using Mobil 1 10W30 and I'm going to switch to 10W40 this summer. It gets pretty HOT here in the south.

 

yeah well Flex Fuel Vehicles such as the Dakota Flex fuel requires 5W20...all hemi motors i have ever seen are 5W20....but my general rule of thumb is in summer months use 10W30 cause its a thicker oil yes but it gets so hot that the oil will thin out significantly and if your using a thin oil as it is already then you basically thining your oil out to extremes. Use 5W30 oil for colder months since it is colder it is not as thick and it is easy for the car to crank over during winter time. Thats just my 2 cents im throwing in!

 

x2...that's true...only reason 5w20 is used...better gas mileage. like sddunn said will 5w30 or 10w30 hurt...nope...your gas mileage just goes down. I think a thicker viscosity oil would be better for a lot of us who like to see high rpms often. we obviously don't care about mpg

 

the article would have more credibility if it was produced by a company who offered 5w20

 

Here's another article on the downside to 5W-20 oils:
http://www.machinerylubrication.com/...?articleid=518

To summarize the anti-5W-20 points of the article...

Thinner oil results in better MPG. Auto manufacturers are concerned about fuel economy. The manufacturer faces big fines if the fleet of cars it produces falls short of the Corporate Average Fuel Economy (CAFE) requirements imposed upon them by the federal government.

If an SAE 50 oil at 260°F is as thin as an SAE 20 oil at 190°F, imagine how thin the oil film becomes when you are using an SAE 5W-20 and your engine overheats. When an engine overheats, the oil film becomes dangerously thin and can rupture.

To determine if SAE 5W-20 oils provide the same level of protection as SAE 5W-30 oils, Dagenham Motors in England, one of the largest Ford dealers in Europe, was consulted. SAE 5W-30 is required for warranty purposes in England, and SAE 5W-20 is not even available. If SAE 5W-20 were better for both fuel economy and wear, why would Ford not recommend it for its same engines in Europe?

 

I have to admit I am so clueless when it come to oil raitings, I should get smart on it as I manage an auto shop where we do oil changes (but they are not our focus). Here is a question, yes 5w-20 is thinner and will break down sooner, what about the synethic oils in the same weight, they can handle higher temp befoe breakdown, right? So wouldn't running the 20 be best for mpg but run synethic for protection? I run the synethic in my truck. I guess the way I feel about it is if I run what the car says it keeps me out of trouble if something happens.