5W-20 vs. 5W-30?

[Eric]

The Ford owners manual and the oil cap indicate using 5W-20 synthetic blend oil in the 5.4 Triton 3V. I was wondering if anyone out there has done any testing with 5W-30 full synthetic?

The reason I ask is that Costco regularly offers a $10 off coupon for 6 quarts of Mobil I 5W-30 oil and it's a hard deal not to pass up. My understanding behind the 5W-20 recommendation relates to the higher flow rate and thinner viscocity which allows slightly better fuel economy. As for protective qualities one would think the full synthetic would be better than the blend (as long as it's changed within the recommended mileage intervals) and that the difference between the 20/30 weight would be more of a heat issue, in other words if you live in a hot climate vs. cold climate.

Just wondering if there is a risk in using the 5W-30 Mobil I.

 

[joezek]

My plan was to use Mobil 1 5W30 or Amsoil 5W30, but before I do anything with changing oil brands I always consult the crew at bobistheoilguy.com. It's an excellent forum, those guys are the absolute most technical fanatics I've ever talked to in my life when it comes to motor oil/fluids.

They're life seems to consist of trying every brand of oil, and taking oil samples and having them tested in the lab. They all share their results of miles driven, type of driving, type of gas used, type of air filter used, and then how much oil life was left in the used oil sample and how much it started to break down etc. They will have a great recommendation based on all their tests/results etc.

 

[ELVATO]

Shouldn't be too much of a problem, other than a slight loss in MPG.

Granted, one of my friends who browses BITOG forums says that appararently Mobil 1 moved their supply plant to a new place, and the quality has dropped as a result.

What does the total price for 6 qts come out to?

 

[Eric]

As I recall it was right around $20 per case of 6 after the coupon. Unfortunately you need 7 quarts!

 

[trdragons44]

As I recall it was right around $20 per case of 6 after the coupon. Unfortunately you need 7 quarts!

what motor do you have? last time i checked all 4.6/5.4 all use 6 quarts of oil with filter change.

 

[Eric]

2005 5.4 3 valve, takes 7 quarts.

 

[GAINMOB]

so you want to change weight just to save $10? just to waste it somewhere else? there's a reason why the manufactures recommend things...just my $.02 always do a pro/con analysis...save $10 verses loosing mpg...which will cause more refueling...maybe more than $10...again...my $.02

 

[Eric]

That's assuming the engine actually gets measurable better mileage using the 5W-20 right? My assumption there is no difference, but I could be wrong....

 

[GAINMOB]

true.........

 

[Eric]

Well I will report back as to any difference as after reviewing Bobtheoilguy website I went ahead and used Mobil I 5W-30. I have pretty good records on gas mileage so I can now compare....time will tell.