Service intervals

[Gregs24]

5W20 signifies the viscosity at 40C (5) and 100C (20) so both 5W20 and 5W30 are identical from cold but 5W30 is slightly more viscous at operating temperature. Ford specify 5W20 for the Mustang V8. Theoretically 5W30 will slightly increase fuel consumption and reduce power compared to 5W20 because of the slightly higher viscosity when up to temperature, but in reality it isn't hugely different either way. Theoretically you should see slightly higher oil pressure which is a function of viscosity, but higher viscosity doesn't mean better protection. The higher viscosity may potentially result in poorer penetration of journals and bearings so providing less protection from wear because the engine is designed for lower viscosity oil. You need to run the oil that the engine is designed for.

The answer is to stick to 5W20 as Ford suggest.

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[TimG]

google "italian tune up" basically put diesel oil in run it hard drain it and replace with normal, oil is oil as long as you're not wildly out of spec's it'll be fine, i'd never run anything as thin as a /20 as i tend to beat on my cars

this guy has some very interesting tests / explanations (including maths for nerds) regarding stuff like oil etc
https://www.youtube.com/user/EngineeringExplained/videos

By diesel oil do you mean lub oil for a diesel engine or diesel fuel (DERV)?

 

[hinch]

engine oil nice thick stuff get it up to temp give it a good beating drain it and then put normal oil in note i'm not saying do this on a modern mustang! but it was an intended to point out that oil is just oil and really you don't need to worry about having exactly the "manufacturers" spec in the car as long as you are aware of the consequences and limitations.

for example you wouldn't run a 0/20 on a track its far too thin as on a track you operate at much higher temperatures, this is also why the factory gearbox and diff oil in the mustangs is so bad and clunky and why a lot of horrible transmissions are fixed by after market oil.

 

[TimG]

engine oil nice thick stuff get it up to temp give it a good beating drain it and then put normal oil in note i'm not saying do this on a modern mustang! but it was an intended to point out that oil is just oil and really you don't need to worry about having exactly the "manufacturers" spec in the car as long as you are aware of the consequences and limitations.

for example you wouldn't run a 0/20 on a track its far too thin as on a track you operate at much higher temperatures, this is also why the factory gearbox and diff oil in the mustangs is so bad and clunky and why a lot of horrible transmissions are fixed by after market oil.

Hinch the manual gearbox on my 2016 has always felt a bit notchy & clunky & that a change to which oil may improve it?

 

[hinch]

i swapped this stuff
https://www.opmustang.com/store/p7/...NG_-_Transmission_and_Rear_Axle_Fluid_.html#/

(you can buy it direct from BG in the UK)

but others have found swapping out the shifter its self to be a gearbox mount rather than body mount has helped

 

[Gregs24]

Please never put oil designed specifically for diesel engines in a petrol engine, especially one like the Coyote. Diesel specific oils are frequently more viscous (and as per previous post this could have a devastating effect on wear) as well as containing far more detergents that will wash the bores of petrol engines.

The old 'Italian tune' was more to do with thrashing the engine to clean off coke deposits from plugs and valves to restore performance. No need for it now with better controlled fuelling with injection systems.

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