Hey everyone. I have a 2002 Ford F150 with 30,000 miles. I have used Mobil 1 5w-30 synthetic beginning at 3,000 miles. In the owner's manual Ford recommends 5w-20. Will it harm the engine if I use 5w-30 instead of 5w-20, or switch to 5w-20 at this point? I would have purchased Mobil 1 5w-20, but I haven't been able to locate it in stores. Thanks.

 

No you havn't hurt anything. Use either one.
5W20 Motor Craft is much easier on the wallet. Only cost $15 to change the oil plus the cost of the filter.

 

What about 10w30 in the summer?

 

No harm, no foul. No real difference between 5w-30 and 10w-30. Mobil 1 would be a good choice for extended runs, anything over the Ford recommended 5K. I've used both the Motorcraft 5w-20 and Mobil 1 5w-30 and found no difference in fuel economy. Motorcraft in the 5 quart jug is a good deal at Wally World and will save you a few bucks if your doing standard 5K or less oil changes.

 

Thanks i have been using Motorcraft 5w30 i think i will use 10w30 MC

 

My 2000 I used both 5w30 and 5w20 oil durring the time I owned the truck had no problems out of either one.

 

The ? was 10w30.

 

I didn't see anything on 10w30 until you said something about. You can use it but FORD don't recomend it on the newer engines.

 

Why do you try to 2nd guess the people who designed and built your engine?
If it says 5/20w then use it. This is not your great grandpa's Model T.
It's a modern engine that uses a modern oil

 

In simple terms, multi-grade oils;

10W will not flow as good as a 5W (W being winter) when cold (ie; freezingg winter cold startup).

-20 is the viscosity at 212 fahrenheit, so a 20 weight. 30 weight is different than a 20 weight.

Essentially, 0W-20, and 5W-20 are the same, 0W "replaces" 5W because it can flow better in the winter and still remain 20 weight when it's "hot".

You get into the different technicalities of each different manufacturers oil is another thing and if that multi-grade is the same as another brand under the same condition.

 

In the first place my truck calls for 5w30 not 5w20

 

Correct, however in early 2000ish they aparently did some more test and found that the 20 weight oil was just as suitable to use as the 5w-30 they originally stamped on their Modular motors, so now all the manuals and oil caps say 5w-20.

 

the differing viscosities matter very little to a modern engine unless you are using the truck heavily through a northern winter. Ford's recommendations are merely a suggestion, rather than a hard and fast rule. All the viscosities are blendable as well and should be flowing the same at operating temperatures.

However, straight weight oil may not be advisable in these engines because of potential oil pump fouling , but even that would not be a problem in the normal lifespan of these trucks for most people.

 

Are you refering to the drunken crack monkies who put 4 threads in the cyl heads so they blow out easy, then take 8 years to finally re-design them so they won't come out without breaking off in the head? Then they don't issue a recall and pretend like they know nothing about how it could happen. They train their employees to tell the customers "screw you."

Yeahhh.. Right.

10w30 isn't gonna hurt it and I have personally seen enough people run it in these newer modular motors with no harm. It's your truck, your money, and your responsibility. Do what makes you happy.

I'm just saying that just because they designed the motor and speced the oil doesn't mean it will blow up if you run anything else. I feel 10w30 is more shear stable than any of the other conventionals or blends.

The 5w20 has nothing to do better protection on a modular motor with OHC, it actually causes slightly more wear than the x-30's. This is proven in UOA reports. The 5w20 is only for CAFE requirement crap (tree huggers trying to get .0000000001 better MPG)

If it were as simple as making clearances tighter and pouring thinner oil in, it would have been done years ago on those moddel-T's

 

Let see those reports.