I changed the engine oil & oil filter this morning in our new '83 . The oil I drained out was the blackest oil I have ever seen! I think it was absorbing the light in my garage! It was supposed to have been changed less than 4 months ago. I don't believe it.

My question is whether anyone else has encountered really black oil in the engine, and if so, any idea what caused it? Especially after less than 4 months.

The engine now has 5 quarts of Mobil 1 10-30W and a new Toyota oil filter. I hope it's happy.

 

How many miles between the last oil change and the new oil you just put in?

 

No way to know. The odometer has been broken for several years (according to what I see on Carfax). All I know--and it's very little--is that the oil supposedly was changed by one of those "Quicky Lube" places on November 20, 2017. We bought it on Dec. 12, 2017--less than a month after the supposed oil change--and have only driven it a couple hundred miles at best. The PO could have driven it a little or a lot in that month. Or maybe he got charged and those guys did nothing. Nah, that wouldn't happen. Sure it wouldn't.

 

Is there a oil change sticker on the truck or did you get a receipt from the PO?
I wouldn't be surprised if it wasn't changed. Jiffy Lube was essentially put out of business recently because they played games. The Valvoline name took over the locations.

 

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How did the filter look? Yeah the PO may have brought it in and they never changed it .
they did that to me once when I was a teen. My dad took me back there and raised hell. I got 3 free after that.

 

What causes oil to turn black?

Typically carbon. Lack of frequent changes, overheating, no cool down time between lots of heat and engine shutdown.

Modern design combats some of this with the electrical fan that stays on after you shut the engine off.

You learned a valuable lesson, maybe for cheap.. Always inspect the oil (pull the dipstick) when buying a used vehicle, it is not foolproof but may give you some insight and a bargain point.

 

Yep, it was a Valvoline place, and yep, I also forgot to pull the dipstick when we looked at it.

No receipt--just the note (fake?) on the Carfax report. I didn't rip the old filter apart, but the inside looked like a lump of coal. Maybe Santa thought I had been bad?

Time to move forward. Obviously the oil was NOT changed a month before we bought it. It is what it is.

 

Which is one big reason I have never used those places. Your story is very familiar. They overfilled a buddy's car and the oil frothed from the crankshaft on the freeway and oil went EVERYWHERE in the engine compartment. Almost caught fire. A huge mess. Their answer: "those things happen". Yeah, when retired burger flippers are what you hire to do the work.

 

Could be that they changed the oil for the first time in a long time, just before selling the truck. Careful running synthetic. Might be just what your engine needs to clean all the sludge off the oil seals, which may be the only thing keeping them from leaking.

Run for a few dozen miles, change the oil again. Do this till it looks better, then just keep a close eye. Personally I'd use something cheaper than Mobil 1 for this...And of course depending on how well everything is tuned, it might be running pretty dirty.

 

My buddy (not a car guy) got his oil changed at one of those shops, they either didn't replace the oil and drain plug, or only screwed it in finger tight. The motor seized after 500 or so miles without a drop of oil in it.

 

I'll be keeping a close watch to see what happens. Good thing I don't drive it much. I'm in the process of rejuvenating it.

 

Local shop once told me there biggest buyer of replacement motors was Wally World quick change.