MotorCraft 5W-50 Engine Oil Vescosity

I just bought a 2013 Extended Cap SVT RAPTOR (October/2013) and I Changed the oil once after 2000 KM (1242 Miles), I used the oil at the Ford Dealer, I asked them to use the 5W-50 fully senthytic grade oil (MotorCraft), due to the hot weather I thought that the 5W-20 Fully senthytic oil will not withstand the 50C+ in the shade (122F+) daily.

Is what I did will harm the engine some how?

Could anyone help please.

Thanks alote

The temps in your engine should be close to a constant and around 200 degrees.. 5W20 was designed for it and this is what you should run. The ambient air temps are not as critical as the engine temp since the engine temp will always be more, or your truck becomes the least of your worries if the outside air gets to 200. 20 vs 50 viscosity is simple the oil would be to thick to properly lubricate into the small oil passages that 50 will not flow properly. So yes use 5w20 if not available 5w30 but no more than 30 the oil is to thick otherwise...

Thank you for your reply, if any vescosity over 30 is too thick then why are there other vescosities over 30 since mostly all american autos are recommending from 5w-20 to 10w-30, and why other grades like 0w-40,5w-40,10w-40,5w-50,10W-60 or any other grades are unrecommended or considered harmful to the engine. Noting that from my little search that I did would say that the number that comes before the W is lower temp and the number that comes after the W is the high temp that the oil can perform at.
I asked many people about what kind of oil to use in very hot climate and many recommend a higher vescosity, although one told me to stick to what Ford company recommended.
If a higher vescosity oil are there in the market for high temps climate, then what is hotter than 122F +.

The engine is engineered to move oil at a specific viscosity. Unless you're overheating the coolant the ambient temp doesn't matter. Seeing as the engine oil is cooled/warmed by the coolant it is at a pretty steady temperature (~210F) when the engine is at operating temps. Stick with what's recommended.

What you say about the viscosity ratings isn't really correct, the first number is the viscosity of the oil at a low temp (winter rating) and the second is the viscosity at operating temp (210F or so).

Motor Oil Viscosity Grades Explained in Layman's Terms

This is taken from http://www.bobistheoilguy.com/motor-oil-105/

"FYI. The Formula 1 cars that run at 15,000 RPM and higher use straight 5 and 10 grade oils.

Now let me discuss what people think is a similar situation to racing. That is hot summer traffic jam driving. Your car should be able to handle this. If you have problems then you have a problem with your car, most likely in need of a cooling system overhaul.When you drive that car down the road mid-winter in upstate New York or mid-summer in Florida the engine and oil temperatures will be around 212°F. But your Florida vacation is suddenly altered by a hurricane. You have to get out of Tampa, but so do a million other people. It is now 95°F and you are in a snarl. Everyone thinks they need a thicker oil for this situation. This is false.Your engine is not producing much heat at low RPM and low BHP output. The production of heat is relatively slow. It can easily be transmitted to your cooling system. The problem is that your cooling system has trouble getting rid of the heat. The oil and the coolant will slowly rise in temperature. They both rise together. The increase is no big deal for your oil. It goes to 220°, then 230°F. The problem is that the cooling system can only handle heat up to 230°F. After that you overheat the cooling system and the car must be shut off. The oil never got that hot, It was just that the water got a little hotter than its system design.You now see that overheating in traffic is a cooling system problem and not an oil system problem. Do not change to a thicker oil based on your traffic situation."

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They hit the nail on the head. Very smart guys indeed. TO add to what they provided, the thicker viscosity oils are specifically designed for engines meant to run the thicker oils. For example, the 50 weight you are running and the 40weight that you mentioned are more commonly run in diesel engines. You WILL cause damage to your 6.2L if you continue to run a thicker weight oil like that, specifically your oil pump, it wasn't designed to handle pumping that thicker weight oil.

So why did you ask for help then immediately discount it? I smell troll.

Maxx2893 said:

So why did you ask for help then immediately discount it? I smell troll.

Click to expand...

Yea.......I noticed that too.......hummm!

I honestly believe he misunderstands the correlation between the second number and high temp use. Basically, he is thinking that the higher the second number in the viscosity, the higher the ambient outside temp it can be run in. That is not the case. For the OP, the second number in the viscosity is simply the operating temperature weight of the oil, the first number is the weight that the oil "Acts as" when the engine is cold. The second number has nothing to do with the outside temperature the vehicle is being run in.

Thank you all for your help and support and have a nice day.