What weight oil do you use?

[Robottrainer]

I would not use 5W-20 in anything. 5W40/50 will do everything 5W20 except have too low viscosity haha.

What was Ford thinking ....

Not Ford. EPA. EPA is at the route of all evil.

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[Graemecdn]

No, it doesn't. 5W-20 maybe

 

[Graemecdn]

You are correct, 5W20, my error.

 

[mmff88gt]

Send a sample off for analysis and you will change your mind. 5w20 looks fine at first, but the viscosity break down gets ugly. Especially if you're using Motorcrap oil.

I have had my oil analyzed 5 times for my current Mustang GT -- two times after oil changes at about 5,000 miles, 2 times after oil changes at about 7,000 miles, and the last time with almost 8,000 miles. I'm playing the game of seeing how many miles I should really go between changes of 10 quarts of full synthetic. I have always used Motorcraft full synthetic in this vehicle. I used to change every 3,000 miles in my previous vehicles. The most recent analysis by Blackstone concluded with the following: "Based on these great results, you should have no trouble running 10K miles." I am not seeing any viscosity breakdown with Motorcraft full synthetic after having sent five samples off for analysis for my current vehicle, although I have moved up from 5w-20 to 5w-30 since the last analysis just based on Ford's changed recommendation for more-recent model years and my gut feeling that 5w-20 is not really an appropriate oil for a high-performance engine.

 

[S550HPP]

The first numeral denotes the lowest API viscosity and second denotes highest so 0/5 W40 or even 50 keeps all engines happy ensuring the correct viscosity in low and high temps though may not be the most fuel efficient or lowest incremental emissions.

I have run 5W40 in all extremes from bone chilling freezing (start no plug in) to many hours at 110F with engines looking new at 60000 miles by which time I usually get rid of the vehicle.

I do change at 3000 miles simply because I do a lot of short trips with turbo, which is deemed extreme operating environment. Only costs me $80 to change with filter and Pennzoil euro synthetic ....so much cheaper than $8K engine.

 

[sholxgt]

I have had my oil analyzed 5 times for my current Mustang GT -- two times after oil changes at about 5,000 miles, 2 times after oil changes at about 7,000 miles, and the last time with almost 8,000 miles. I'm playing the game of seeing how many miles I should really go between changes of 10 quarts of full synthetic. I have always used Motorcraft full synthetic in this vehicle. I used to change every 3,000 miles in my previous vehicles. The most recent analysis by Blackstone concluded with the following: "Based on these great results, you should have no trouble running 10K miles." I am not seeing any viscosity breakdown with Motorcraft full synthetic after having sent five samples off for analysis for my current vehicle, although I have moved up from 5w-20 to 5w-30 since the last analysis just based on Ford's changed recommendation for more-recent model years and my gut feeling that 5w-20 is not really an appropriate oil for a high-performance engine.

Curious, what was your starting and ending viscosities? Asking because mine had the same message from Blackstone despite the viscosity going down significantly. Likely due to fuel dilution. I will say that the 10 quart capacity in the coyote probably helps quite a bit. The car I had tested was 6 quart capacity.

 

[SheepDog]

This thread is like a Virus. Even though I ignored it, I still get notifications. I sure am glad we have yet another "which oil?" thread to reference. Mustang6G is going to have to buy a new server just to store the 10 Terabytes of dribble across all postings

 

[mmff88gt]

Curious, what was your starting and ending viscosities? Asking because mine had the same message from Blackstone despite the viscosity going down significantly. Likely due to fuel dilution. I will say that the 10 quart capacity in the coyote probably helps quite a bit. The car I had tested was 6 quart capacity.

Here are the viscosity numbers from the five Blackstone reports I had previously referenced for 5w-20 Motorcraft full synthetic:

 

[engineermike]

The spec for 20 is 6.9-9.3 but blackstone almost never has this right. I don’t know why.

 

[mmff88gt]

The spec for 20 is 6.9-9.3 but blackstone almost never has this right. I don’t know why.

Still in correct spec, but good to know. Thanks.

 

[engineermike]

Btw oil viscosity can go up or down while in use. It can go up due to oxidation or down due to shear thinning or fuel dilution. The bigger the summer/winter split and/or lower quality base oil can contribute to shear thinning. My experience has been shear thinning happens more often than the other degradation modes in these cars.

 

[50BMG]

Another thing to consider is that any euro a3/b4 rated oil is specifically designed for high performance engine protection…unlike us api oils that prioritize emissions and fuel economy. The a3/b4 oils are required to have a higher hths, higher zddp concentration, and higher tbn, among other things. As such, the lowest sae grade that can meet the spec is 5w30. Castrol makes a 5w30 euro a3/b4 that works very well if you’re not wanting to take the plunge all the way to a 40 or 50, but want additional protection from a high performance oil.

Holy Crap!
I now have a Gen.3 Aluminator motor in my car (along with custom exhaust/no cats) and I just looked at the FPP build sheet specs and Ford recommends 5W-50 full synthetic oil in it!
I might try out this Castrol Euro A3/B4 oil in it (this is my second break-in oil change on the motor. First at 50 miles, I'm at @700 miles right now).
I can only find the 5W40 locally. If I'm not really tracking the car, this "should" be plenty thick for for my "spirited" driving style, right?

 

[K4fxd]

5w-40 should be fine but FP specs 5w-50 for protection reasons.

 

[50BMG]

5w-40 should be fine but FP specs 5w-50 for protection reasons.

I agree with you Dan.

I ordered some of the 5W50 from the local APS yesterday afternoon. Hope it's in this weekend as I really want to get fresh oil in the beast so I can start running it the way to was meant to run.

 

[xcm77]

've been using oil that's 1qt and it seems to be fine

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