Can someone please tell me why Ford specs such a light weight engine oil for the F150? And is it ok to switch to a heavier oil or should I stick with the 5W-20?

Thanks.

 

i was told by some mechanically inclined friends that the newer ford engines spacing in all the internal parts is a lot less than I guess what it was in the past. This all came up over them finding out I pay to get my oil changed. They said that anything thicker would do more harm than good in the long run.

 

The ford techs say use is , i use it and over 93k with no problems.

 

The answer you get varies with the thread.
Some say it is just for additional MPG, others say it is engine specific for clearance issues ( even though earlier modulars had 5-30 on the engine, but Ford did issue a TSB to use 5W20 on all modular engines ). Some members back in '01 / 02 said their dealers did not have 5W20, and used 5W30 ??
Don't ask me how you get a clearance between parts that 5W20 to 5W30 would cause a problem ?

I always had been one to use 15W40 in my trucks, but with my '01 and my '06 I have stuick with 5W20 or 5W30.

I think the heavy oil route only made me feel better, and might not have done anything better then the factory recomendation.

Lots of members have 100K + miles using the recomendended weight, without problem, so I guess I am going to stick with tried and true method still, I cringed the first few oil changes, and after that I did not think about it any more.

If you feel the need, you can try a search on oil* in the engine section, and read through the posts.

 

I use 5W50 Synthetic. No problems so far. But as has been mentioned use what is called for in the manual and you will be fine.

JMC

 

Cool. Thanks for the info everyone!

Great board by the way.

 

I am one who changes his oil religiously every 4000 miles with Motorcraft 5w/20 synthetic blend and a Motorcraft FL820-S filter. I did my 104,000 mile oil and filter change last week, and I still have no need to add any oil between changes.

The oil and filter can nearly always be found at my nearby Wallyworlds at very reasonable prices (around $2/qt. for the oil and $3.00 to $3.50 for the filter. My opinion is at those prices why not use the factory recomended stuff?

 

The advent of 5/20 oil was for lower emissions. It wasn't for stricter tolerances in any parts. The first vehicles to really use it were Honda LEV's (Low Emission Vehicles) and then on to the newer Honda ULEV (Ultra low...) and then Ford realized the benefit and the rest is history

 

The the parts guy at dealership that I deal with said that after 1999 you need to use 5/20. He said that they had some engine failures when it was not used. When I went to school as a millwright they taught us (instructor was a mechanical engineer) that it is best to use the thinest oil that would support the load in bearings because thicker oil will cause more friction in the bearing and more heat, which is bad for bearings and oil. With the use of CNC machining, there is more consitant machining which enables closer tolerances and smaller clearances - thinner oil is needed. I would definitely follow manufactures recomendation.

 

I thought that the reason the oils have gotten thinner was due to the improvements in oil producing technology. Crossing synthetics and full synthetics take longer to break down and makes it easier for your engine to turn creating less friction in the internals. A thicker oil could make the engine work a little harder to turn causing a decrease in gas mileage. Perhaps if the engine had over 100,000 miles a thicker oil would be better. I would say like the others and stick to what the manufacturer placed to begin with. It was for a reason.(whatever it may be).

 

Considering that Ford has spent billions of dollars in research and development, I would stick with their recommendation. Newer engines do have tighter tolerances. Older small blocks had tolerances measuring in the thousandths of an inch. The newer modular engines have tolerances measuring in the hundredths of a millimeter. Much tighter indeed! Putting either 5W-20 or 5W-30 is fine in a modular V-8. The engines didn't change when the thinner oil was introduced. It was to improve fuel economy. Just don't use 10W-30 or anything thicker. The oil won't be able to get inside the clearances and you'll end up with engine damage. I've seen it happen.

 

closer tolerances...in the newer engines.. 5w30 is same weight but handles more heat then 5w20 does. but 5w20 will expand less when it heats up. so it is used just to prevent any problems with loss of oil pressure.

 

How is your oil going to get lower emissions unless your burning it? do you mean reduced friction thereby increasing efficiency?
My modular book says that if you use oil thicker than 5W30 it will affect the bleed down rate of the valve lash adjuster. If the viscosity is to high it could pump the adjuster right off the valve seat. Granted they are building engines to turn 8500 RPM. The average engine would probably tolerate a little more variation.

 

yeah an no one likes to get pushed out of their seat

 

I didn't design nor study it, I just know thats what I read about it and I know honda was the first to use it, and that the first cars they used it on were Low Emission vehicles. I would guess less heat and better gas efficiancy lead to lower emissions