On our 2003 it recommends 5W-20. I'm wondering why?? What's wrong with using 10W-30?? Thanks.

 

The engine is designed for 5w-20 for the follwoing reasons:
faster lubrication on start up when cold
better fuel economy
much closer tolerances in engine assembly with newer engines
better heat dissipation

IF you go to heavier oil you will negate all of the above and it will cost you more to operate and it will wear out sooner.

 

Good enough - thanks.

 

Isnt there something else that you need to consider: oil breakdown.
5w-20 is really thin oil. If you live somewhere where it gets hot, the oil could very easily thin out too much and fry your engine.
For my '99 F-150 I am supposed to run 5w-30, but I run 10w-30. This is mostly because 5w-30 reaches its limit at about 90 degrees (air temp).
In the summer it often gets about 90 degrees, so I run 10w-30, which is rated for over 100 degrees, which it almost never gets above here in Wisconsin.
I may suffer some on fuel milage (which is the reason for the thinner oil), but Id rathar burn a little more fuel than to cook an engine.
Also, is that 5w-20 recommendation for synthetic oil? That seems like awfully thin especially if you are running petroleum-based oils, which have a much lower flash point than synthetic oils.
I say run 5w-20 while you are under warranty, but I wouldnt be running that grade once the warranty is up.
I still say that thinner oils are being recommended so that the automakers can keep up with the emission regulations without changing their current technology.

 

I tried Quaker State Synthetic in my Escape. Started better in winter and got 3-4 mpg better milage on highway.

 

30 weight is 30 weight reguardless if it starts at 5w or 10w or straight 30! I've used the recomended 5w30 for years in AZ heat and have no problems. Start up is probably where most wear happens and 5W30 would be better here than 10W30. Our Tribute says 5W20 but also in the manual it says I could use 5W30 in hotter climates so I do.

 

I may date myself here, but all this about heat and needing heavier oil is for the birds. I still remember 10w40 and all the hype about going to 10w30 and how much better protection 10w40 would give. The facts are 5w30 is specifically made for tighter fitting engines period! 10w30 is outdated and the engines of today need to use the lighter oil. You wont loose lubrication quality because it's lighter, actually its better because it can get where it's needed and faster. 5w20 is designed to improve fuel mileage. I work on them everyday. I am ford certified senior master tech and ase certified in all areas.

 

I had a 98 F150 with the 4.6 Triton V8 and ran 5w30. I'm in Texas where it gets well over 100 degrees. I put almost 150k miles on it before trading it for the Escape in late 2002. No problems. I'm running 5w20 in the Escape and I'm approaching 60k miles w/o problems. I agree it's due to the tighter tolerances and improving mpgs. I remember running 10w40 back in the 70's and I haven't lost an engine or had one smoke running what's suggested by the manufacturer.