I have a 2001 F150 4.2. Filler cap calls for 5w20 oil. I put in 10w40. Does this cause any problems?

 

long term i would things so jsut because it is very think and start ups require thin oil to circulate better... ford actually had 5-30 on their trucks for a long time and the only reason they sed to switch to 5-20 (or why they switched to recommending it) was increase in gas mileage ( about .2 mph) or something small. but when u produce a fleet of millions of vehicals that adds up fast. so do the average person that is nothing really, one down shift to pass someone will burn it up. but to them that gives they better mpg rating and less to pay since they have better gas milage as a whole.

 

There are a number of reasons that the 10w-40 is not a good choice for your engine. Ford recommends a 5w-xx in all of their engines. reason- it gets to the valve train quicker and reduces wear. Your 10w-40 isn't going to provide much, if any, startup protection as it will be slow to get to the top of the engine, especially in cold weather. Now for the 40 viscosity. It will not have the Ford specs, either 929 or 930 because only 5w-20 or 5w-30 qualifies. Oils with these specs will not move out of their respective viscosity ranges, have fewer deposits, run cleaner longer, and don't produce the sludge that your 10w-40 will. Your 10w-40 when at temp will retain more heat- simple physics- a thinner fluid releases its heat quicker so if you run a thinner oil, your engine internal parts will run cooler. And no you can't judge the temp by the coolant temp because it is just that, the coolant temperature, not the internal parts temp. The 10w-40 will be slow to drain back out of the heads as Ford designed the drainback system for a much thinner fluid. If you drive at high RPMs you could be starving the engine for oil or worse yet, the pump could go into cavitation and pump foam instead of liquid oil. There will be more resistance inside the engine at any RPM which is why the fuel mileage will go down some but your engine is having to work harder to overcome that resistance. There is no reason not to run the correct oil in your engine. The recommended oil is a much better oil than the one you are running. I would suggest changing the oil ASAP to the correct 5w-20 with a brand of your choice but make sure that it has the Ford spec 930 on the bottle. Not all 5w-20s have it so look before buying. The 930 oils have been turning in some of the lowest wear metals in the Triton series engines. It is the best oil on the market today for your engine.

 

Interesting points, as I just did my first "in the carport" oil change for my '02 Lariat today. I gave the truck 6 qts of Mobil 1 "Truck and SUV" (but still full-synthetic) 5W30. In any event, both the single quart bottle and the 5QT jug indicates that it meets Ford's spec 829; but my logic was that temps in my neck of the woods have been slipping into triple digits recently, and they're not going to drop back down for a few months - probably mid September. Kinda like glossing over all the "finer points of driving on ice" in the owner's manual; because there's no mention of how to safely drive in a sandstorm, or vehicle and passenger survivability measures in a Sonoran desert summer!

OT: As I said, this was the first time I changed the oil myself since buying the truck in December - the first time around, I used my "free oil change certificate" from the (Ford) dealership where I bought it. Now I know why I had received a folder full of maintenance receipts -98% of which were for lube/oil changes- from the previous (original) owner. After 15 minutes on my back on the hot concrete, figuring out how to get the new filter back up in there without pouring the $20/gallon oil with which I "preloaded" said filter all over the front diff; I was sorely missing my old F100 with its Dana 44 solid axle and simple reach up to the side of the 390! I had previously thought the filter on my '91 Silverado (which the present F150 replaced) was a royal PITA to replace. I was wrong.

 

Are you sure Ford recommends 5w-xx in ALL of their engines? I know I've had other Ford vehicles that recommended 10W-30 in the owner's manual. Unless maybe you mean just the new Ford engines?

 

This has got to be mountainqueer right????

 

To meet the federally mandated fuel consumption the auto makers found that running 5-20 or 5-30 oils could free up the engine and meet the requirements. So they designed the engines to use these light weight oils.
But you know what....you, me, or anyone else will never see a difference in mileage if you use a different weight oil.

And racerf150-2 is right about the 5 weight circulating faster when the engine is cold. I run 5-30 in my marine engine during the fall/winter/spring for that very reason. A boat motor will sit for longer periods of time and having a light weight oil in it allows the oil to circulate faster uppon startup. During the hot summer months I run 15-50 for the added protection.

 

That's exactly what I was thinking -- in fact I even went back to double-check the user name.....

 

You're right. I run 10W30 in my 97 because John Deere doesn't make 5W30! And I think that 10W30 is thin enough for south Georgia.

 

so im a mountainqueer because i was in fact right? this coming from a guy who is prob 5 times the age and drives a yota rav 4? my mc race bike has more ballz then that thing