Any harm in...

[BUDSHAD]

Is there any harm done in mixing one qt of Mobil 1 5W20 and six qts of the MC 5w20 in my 2005 Ford F150. 5.4 L engine. The engine has a seven qt capacity . I am just wondering if there is any benefit to this or am I doing something that I should not?

 

[m2200b]

Neither harm nor good - you still have MC basically and it tests ok in your truck.
I wouldn't spend an extra $3 for this but it's ok if you had a qt around to use up.

 

[GoldenRod]

Motorcraft by itself is a way better lubricant.

 

[bighead]

quote:

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Originally posted by GoldenRod:
Motorcraft by itself is a way better lubricant.

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You really hate M1 don't you...

 

[michaelc80]

What is the purpose behind your plan? Do you want to achieve something with it? Or just use up a spare quart of M1 sitting around?

The biggest caveat that I see is the warranty on the truck. On the off chance you do have an oil related failure I can imagine the problems your brew might cause when you try to get it covered under warranty.

 

[m2200b]

The warranty says use 5-20. He's adding 5-20.
Its all SM. No warranty tells you what brand of oil to use just viscosity and API rating.