So Ford recommends 5W-20 in the owner's manual and on the oil filler for the 2010 GT (I'm pretty sure it is the same for 2010-2011 GT and V6 and probably others too, I don't know) . . . . but in another thread it was suggested that 5W-20 will give slightly improved fuel mileage but at the expense of more wear on the engine parts.

Can anyone comment / elaborate on this; maybe some links with the facts on this?

thanks in advance!

 

Interesting! Id like to know now as well. But I dont think Ford would recommend using a grade that contributes to wear on their engines.

 

Some clarification would definitely be nice...

 

I'm going to tell you what my Dad told me since he used to be a chemist for an oil company. The reason they recommend such a light oil is purely for the tax credits on fuel economy. Yes your engine will most definitely wear out faster, but they don't care, our government has set up a system where being green is better than actually making a vehicle reliable. It's pure BS and I suggest 10W30. That's what we run in our cars but we're in Florida so you may want to vary it a little and even mix if you know what you're doing. In the summer I mix 20W50 and 10W30.

 

Main reason: viscosity. All of the current engines are overhead cam with aluminum heads. If the oil is cold it will take substantially longer to build oil pressure in the heads, leading to early wear / failure. Now, if you live in Florida or some other place where you need A/C 24/7/365, run 50 weight. Based on my time in Ft Lauderdale and Houston, it's warranted by the (MUCH) higher underhood temperatures. Otherwise, you might consider going with the recommendation.

Or if yours is a race car, subjected to constant full throttle abuse, run something heavier.

 

Trust your manual. There are plenty of 4.6 street ride's with over 100k using 5w-20. And they've just thrashed the new 5.0 in testing before its release, checked wear, and stated everything was within tolerance.

It would be different if you were racing and living at redline all day (or in very hot climates as suggested. But my summer temps here in the mountains range from 40 to 90 each day so I'm not going 10w-30 or 10w-40).

I know it seems light (back in the day multi-weights got the same criticism over straight 30w), and I could understand going to 5w-30 after you've got a lot of miles on it where tolerances have loosened a tad, but Ford engineers know how they designed the engine - and back it with a warranty.

Besides, most wear occurs on cold start up.

Yes, and the VCT probably factors in too.

Plus - the radiator/cooling system is designed to prevent the engine & oil from overheating and thinning beyond spec, right?

 

So the issue with cold oil is better with the "light" multigrade -- the 5W means it acts like a 5 weight when it is cold, meaning it can still flow on cold startup

Yeah, I remember the old days of single-grade oils, when you had to go to a lighter viscosity in the winter and heavier in the summer . . . but I thought that had all changed with the mulit-viscosity oils . . .

And again the cold startup is better with the lower viscosity, right?

I think the downside to the low viscosity portion is that the film is more easily broken so that's why the higher viscosity is needed under heavy loads . . . but that only matters if the oil has a chance to form a film in the first place which it can't if it isn't there because it is too thick . . .

 

Right.

Hence the need for Motorcraft's synth blend at a minimum, regular oil changes, and maintaining your cooling system.

And perhaps the 5.0 went to a larger oil capacity in part due to this since it has much more power, compression & heat - but notice they did not go to a heavier blend oil.

I know some readers insist on full synth but having extended oil changes does not interest me. I want those blow by gases and contaminents out of my crankcase. So for me, the added cost of full synth is a waste. I use the Motorcraft blend in my 4.6, and all my vehicles get changed at 5k max. But I hardly put more than 3k on each of my rigs so I follow the once/year minimum rule.

 

I would refrain from using heavier oil. The orifices that lubricate the engine (especially the top end) are sized specifically for a certain weight of oil. If you run heavier oil, you run the risk of starving parts of the engine. To me, it would be a huge gamble to run something other than what is recommended giving the fact that if you fry a bearing or something, Ford wouldn't have to pay a dime if improper fluids were used. And I, for one, wouldn't want to pony-up $6000 out of pocket for a new engine. Personally, I've been running 5w-20 in my F-150 for 7 years and it is still running like the day I bought it. When I take delivery of my 5.0...I'm running 5w-20. There may be certain circumstances where you could run other weights I suppose...but you'd have to read your manual and see if it allows for the exception.

 

Correct.

Automated machining processes over the last 23 years that I have worked for Ford makes comparing the old 5L vs the new one like comparing a sundial to a Swiss watch. I know, I used to build them in Windsor; I actually started Ford working on the line building engines in the plant that makes the Coyote.

Unless you're running into extrmely high temps in a racing environment you should stick to the recommended weight; IF you have any kind of engine failure that may be oil-related they DO check both your oil change records and what you have in it (been there, done that).

DJ 88 Fan, I used to run 20W50 when I used to drag my Torino, but I built the engine for those tolerances. That stuff's like syrup and you run the risk of oil deprivation especially at startup, where the most wear happens -- you do what you want but don't give that advice to other people. Your dad might have been an oil chemist but he never worked in an engine plant. Yes, gas mileage counts towards CAFE and lighter oil helps gas mileage but at the same time no manufacturer is going to cut corners and risk replacing engines under warranty for CAFE regs. The engines are built to tolerance -- and more importantly, they are built consistantly to a tighter tolerance...

 

Just a thought here coming from a vtec car to this torque monster all i can ask is does the oil weight have anything to do with the Ti-VCT ? I know it was 5-20 in the past life (honda) and oil level was important too low oil level no vtec as well as good temps in the motor .. I'm just saying ya know ..
How Ti-VCT works

 

Go youtube and search for 5w-20 petro canada. There is a test of 5w-20 and other oils in the temperatures bellow -30'c in russia. You will see difference yoself. I use also same as recommended for my 2010 gt

 

The actuation for the TiVCT comes from oil pressure, so I would tend to think that an oil with a higher viscosity than the spec oil would effect the cam timing somewhat. As another poster eluded to, in the chance of an engine failure, the very first thing the service rep from Ford will have done is to analyze the oil. That will tell them exactly the age, grade, and brand of oil used. You don't want to give them any reason whatsoever to deny your claim. That is why I will only use the 5W20 Motorcraft stuff in my cars.

 

whew, I feel better now, glad we got that straightened out!

I'm sticking with my old faithful Mobil 1 5W-20, changed when the oil life meter says it's time . . . unless I try something "better" . . . or if anyone comes up with anything to support the thicker oil.

 

2010 V6 calls for 5W-30. At least that's what my oil cap says...

 

I don't like to get into motor oil discussions because they can get a little touchy
I'm old and grew up with 'the thicker the better' when it came to motor oil.
My last car had a VVT 4 cylinder engine. I started thinking, 5W-20 is too thin so after a couple of years of using the factory suggested 5W-20 i tried 5W-30 to give me peace of mind. I keep very close track of my 0 to 60 times. My car ran .3 tenths slower (average) with the 5W-30 oil in it. A month later i changed back to the factory suggested 5W-20 motor oil and i got back the .3 tenths of a second on my 0 to 60 times.

For now on, i will always use the factory suggested weight motor oil

 

Me too; I built up a 351W for my '72 Gran Torino when I was young, intentionally spec'd it out to run 20W50. Cross-drilled the crank, chamfered oil holes, hi-volume oil pump, the works. I just remembered the first time I fired her up, almost pegged the oil pressure guage, thought to myself "Oh my Gawd I bent the needle!"

Of course, that makes sense.

Lighter oil weighs less so you upped your horsepower to weight ratio...



....

 

Apparently the PCM watches the oil temperature and if it gets too hot, RPM will be limited until the oil has cooled down.

 

 

Found these notes about the 5w-20 for the Coyote: