Changed my oil, now it's black as pavement-why????

xjsaretheway

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Wilmington/Chapel HIll
I just changed the oil in my 1989 cherokee, after just over 1,000 miles on it but it had been in there since may. With fresh oil, some lucas, and a new filter, i drove it to class and back twice(about 2 miles total) and checked it to see if any had leaked out and it is black, but not the normal "hasn't been changed ina while can't see through it black", it's more of a grey-ish black. Never seen oil quite this color before.
what is the reason for this?
Do i just have a bunch of buildup and gunk in there?
Could this also explain why the engine seems to have such a lack of power?
 
Sounds like a little water from sitting since may. Change the oil & add some restore to it How manny miles are on it? if it's over 150k I would run rotella 15/40 it will help keep a little higher oil pressure at an idle. I wouldn't run the lucas with it in the winter to thick on start up
 
X2 on the water. Short distance like you drove will do the same thing. The engine needs to get warm (operating temp) to evaporate the moisture.
 
It's got 175K miles, and is pretty much only used for off roading, so the past 1000 miles, 400 were highway trips between chapel hill and wilmington, the rest just driving back and forth to the trail and playing in the mud. It sits during the week then gets driven on the weekend, although there was about a 3-4 week period where it wasn't moved while i was locating and replacing the UCA's and front ds. The engine has no problem warming up, it's the keeping it cool part that's the problem.

so it's moisture in the oil? I'll change it again then. I already am running 10-40 in it, will 15-40 really make much of a difference? also, since the oil change is FRESH, is it ok to keep the oil filter i just purchased or do i need another one?
 
For 5 bucks at wallyworld get a new one & yes you will notice the difference in oil pressure when it's warm at an idle
this should be in newbie tech:lol:
 
one last question then I am done. How soon do i have to do this? I have exams all this week, then i'm going to be home for break till jan 1st. It won't be driven till i get back; will it be bad to just let it sit till then or should I try to make some time before I head home for christmas?
 
it would be ok for a week or 2 but I would not let it sit much longer than that
 
Hell, I'd just fire it up and let it idle for 10-15 minutes or drive it for 10-15 minutes one day after finals. That'll get the moisture out.
 
the reason for ther 15w-40 diesel oil is because it has detergents that normal conventional oils don't.... the weight isn't the primary reason folks run it...
 
Do you normally run the Lucas stuff?

It could be .... IF this is the first time using it.... that it's cleaning stuff out of the engine that normally would just stay there.


Matt
 
Erik said:
the reason for ther 15w-40 diesel oil is because it has detergents that normal conventional oils don't.... the weight isn't the primary reason folks run it...
Click to expand...
You are correct! I run it in everything that has over 150K I have always had clean engines
 
didn't know that about the diesel oil, will have to look into that.

and yes, this is the first time the Lucus was put into this engine.
 
justs sitting isnt going to matter

I mean when its sitting all the oil is in the pan.

Im gonna go another way than many
1) When you add the Lucas it has a very high detergent mixture, the black you are seeing is the build up gunk that the Lucas is helping to dissolve
2) if that isnt it Id check air/fuel mixture a Rich AF ratio will black up oil in a heartbeat
 
I don't know if I believe the "condensation after sitting" story (again). If it's gray/milky next time, it's time to pull the heads.
 
I just picked up a YJ with 116K on the clock.. its a 89 model, would the 15/40 benefit this or is it too early?

The jeep will be driven hard
 
NCJeepin said:
I just picked up a YJ with 116K on the clock.. its a 89 model, would the 15/40 benefit this or is it too early?
The jeep will be driven hard
Click to expand...
You would benefit from it
 
SkyHiK5 said:
justs sitting isnt going to matter

I mean when its sitting all the oil is in the pan.

Im gonna go another way than many
1) When you add the Lucas it has a very high detergent mixture, the black you are seeing is the build up gunk that the Lucas is helping to dissolve
2) if that isnt it Id check air/fuel mixture a Rich AF ratio will black up oil in a heartbeat
Click to expand...

That would make sense, i'm sure there has been some buildup of gunk, as this was neglected by the P.O.
How would you check the AF ratio and adjust with a fuel injected engine, and wouldn't you notice some smoke from the exhaust?
 
In '89 the A/F ratio is controlled by the computer, but it's affected by such things as O2 sensors stuck/clogged injectors etc. And you might not see any smoke from the exhaust if the catalytic converter is doing it's job.
 
That is true, although $20 could also pay for another oil change. Maybe I'll get a pic of the color of the oil when i wipe the dip stick off so you guys can tell me what you think.
 
so this thread has heightened my curiosity...i have a 98 XJ w/ 146K....runs fine, no leaks no burning oils or anything...but would it be a good idea for me to start using 15/40 diesel oil ?
what exactly are the pluses and minuses?

sorry about the hijack.
 
The weight & cleaning agents are the key to your question.
When your engine is hot it will hold a thicker viscosity with the 15-40 it helps with the clearences in a worn in engine. Also has spefic cleaning agents in it to get the & keep all that sludge out. Which means better flow of oil thru the internal oil passeges.
 
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