Mulestang

For the most part, my 120k mile 5.4l has lived on a diet of Motorcraft semi-synthetic, or whatever good synthetic oil was cheap at oil change time. I bought a 5-gallon pail of Milesyn recently, and just performed a change with it. At about $21 per oil change for full synthetic, it should be fine for my 5k mile OCI. Getting to my point, the oil I just drained was Penzoil Platinum High Mileage. While not a scientific assessment, I have zero doubts that it was the blackest, dirtiest oil that’s ever come out of that engine. I mean midnight, charcoal, road tar black! I have no doubts that PP performs, but are its detergents that much better than most other oils? Did something weird happen (unknown to me) during this recent OCI to cause heavy crankcase deposits?
If the PP is removing deposits that other oils haven’t, should I switch back to it after this OCI?
What would you do?

FrozenTundraGuy

I've never used Pennzoil, so I can't comment on it. If you are really worried, if you have any of the drained oil left, send it to Blackstone Labs for an oil analysis. I've only used Mobil 1, and recently changed to Valvoline SynPower. The only change I noticed is the engine is just a tad quieter at idle and the oil consumption is a bit improved over Mobil 1. I used Mobil 1 since 1st oil change when new,

Mulestang

I’m not really concerned. Probably more curious. The oil analysis is a good idea.

MilosF150

Black color is carbon and usually means noting. No, your oil didn't magically scrub your motor clean. As long as the oil wasn't noticeably altered (ie gritty, lumpy, smelled funny) oil changing color is normal and not an issue.

Some additives can change color due to high heat.

Oil is oil. Use the proper API spec and weight and keep it at the proper level.

Nothing to see here.

Mulestang

Other than the unusually (to me) black color, it was just oil. Could have just been the oil itself, and nothing extraordinary that it did. We'll se what the OI comes back with.

650NutKase

I wouldn't worry about it. Next time grab a sample and send it off for a used oil analysis (UOA). BTW, I have been using the MileSyn blend 5w30, and loving it!

SCORGE

Get a kitchen strainer when you drain and see what kind of goodies you catch

Eric Kleven

over at the big oil forum, Penzoil's stuff is regarded as a 'cleaning' oil. they like it a lot on dirty engines to pull crud out of them.
Over there, these engines are regarded as being 'real easy' on their motor oil, but they will get dirty/sludgy if not taken care of. Mine was gross when I bought it, we're talking blobs of sludge when I flushed it on the second oil change. It can happen.

Mulestang

I'm pretty religious about my 5K OCI. Always run Motorcraft semi-syn, or whatever brand-name synthetic was cheap at the time (normally Mobil 1). The PP that came out got my attention for sure. I'll post up the UOA when it comes back.

MilosF150

Sludge is water and particulate in the oil usually from condensate from either bad rings, bad PCV, or not running long enough to get hot enough to evaporate entrained water in the oil.

Its a very bad idea to try and flush the sludge with oil. You're literally putting the contaminated EXACTLY where you DON'T want it to go: bearing surfaces. But old motors with poured babbit bearing can take a lot more abuse than insert bearings with super thing spun babbit linings. So I question the intelligence of anyone who says that a sludgy motor should be cleaned buy running it normally with an oil with a higher than normal detergent package... unless they have no idea what they are talking about. Of course a small amount of cleaning is not the issue.. large blobs that can block galleys are.