M1 AFS 5W20 Q's?

Joined
Feb 28, 2003
Messages
11,977
Location
Cajun Country, La.
It's been about a 3-4 weeks since my son did an OCI on my F150. We used M1 AFS 5W20 oil and a M1-209 oil filter. It has been awhile (5-6 years-0W40) since I have used M1 in my engine. I have had this truck since new (6 miles) and have used 5W30 semi synthetic oil (and some synthetic oil) about 75% of the time. The other 25% has been 5W20, 0W40, and various brands of conventional oil.
I always check my oil at every gas fill. When checking it earlier today I noticed it was rather dark already. Since new, I have done an OCI at 3K-5K miles, and a few (3 or 4) at 7.5K miles (currently 165K miles). I always use a new oil filter at every OCI. The only other oil that I have used in the engine, where it turned dark like this, was Pennzoil Ultra Platinum 0W40.
My questions; Is this normal for M1 to get dark so soon? I mean, I have done the OCI's at very low mileage intervals, so the internal engine should be clean, correct? Is the M1 cleaning deposits that were left behind from less expensive oils than M1? As I had stated earlier, the PUP 0W40 is the only other oil that I noticed it turned dark like this. I'm not worried about it at all, just curious. M1 and Pennzoil state that their oils clean up to 40% better than other oils, correct?
I do like the fact that it is dark. This tells me that the M1 is doing its job.
 
The oil could be darkening just from heat alone. If you've ever watched any of those YouTube videos where the oil was put into a coffee carafe for an hour or so, you'd see how they darken just from being on the burner.

And as you said, the oil could be darkening from some extra cleaning as well. However, I doubt that your engine is too awful dirty from the way that you explained your OCI regiment.
 
Last edited:
The oil could be darkening just from heat alone. If you've ever watched any of those YouTube videos where the oil was put into a coffee carafe for an hour or so, you'd see how they darken just from being on the burner.

And as you said, the oil could be darkening from some extra cleaning as well. However, I doubt that your engine is too awful dirty from the way that you explained your OCI regiment.
I agree with that.
 
Back
Top