I recently patched up all the oil leaks on my rig, but i think that i am still losing oil. must mean it is being burned? I know that is not a good thing. I might be getting a little white smoke, but it's definitely not bellowing out or anything. Plus it's cold when i start it and it could just be hot air.

real question, when i put new oil in the engine (full change), how many miles can i expect to go before the oil becomes dirty and discolored? Seems to be happening too fast in mine, do i need an engine flush? i have driven roughly 300 miles over the coastal pass and back, and the oil is discolored. Its not black, and i can still see through it, but should it be that dirty after 2 days of driving?

i can take pics if i really need to.

 

It depends on the condition of the inside of the engine. I've had vehicles that would turn oil black with running 10 minutes.
The color of the oil doesn't mean it's bad. It's doing what it's supposed to do, trapping particles. Not if its gritty then change it, if it still slippery it's probably good. Or take a sample and get it tested.

 

What he said ^

My 86 would turn the oil black by whenever the next time was that I checked it, after changing it. Often the next time I got gas. That doesn't mean it's a good thing...but it's fine.

You could certainly flush, then make sure everything is running well. No unburnt fuel etc. Make sure it's in the best running condition it can be for its mileage, and it'll be the best it can be.

 

my concern is that the engine was rebuilt about 2 years ago, and i would assume that means it should have been clean on the inside. It has been running like crud for awhile because i have been slowly upgrading the intake, carb, and exhaust. now that most of the parts are there, i need to get it running clean as can be so it lasts. I am also worried that i am buying oil.

 

^^ Then I would get the used oil tested.

 

Yes a used oil analysis (uoa) can tell you a lot of things about the condition of your engine. Maybe your ring gap is just on the lose side. Engine oil often doesn't go black because of the crud inside the engine, but because of carbon deposits from the combustion.

 

Good info. Where can i get a UOA done, and how much does it cost? i can't imagine it is very expensive.

 

Blackstone labs is one.

 

I won't try to dissuade you in testing your oil BUT...


Depends on engine condition and oil brand. For example, Pennzoil turns black the second it touches an engine. I have Valvoline in for 4k miles and it might be starting to turn a golden brown color.


It's nothing to fret over. All modern oils, regardless of color, do the same job in an average application: http://xs11.com/xs11-info/tech-tips/...otor-oils.html


The way to tell wuzzup with your oil is to check thickness over color. Old oil thins out. If it's real thin, change it. Black in and of itself is not an indicator of an issue generally speaking.


If you get worried about gunk buildup old-schoolers run some ATF through the engine for a while at idle (just add 1/2 to 1 quart before an oil change and idle in the driveway). I'll add a can of seafoam on occasion and allow a ten minute idle in the driveway before a change, just to clear out the passages. Either one. ATF is pretty effective stuff.

 

Like most everyone else said, oil color alone is not really an indication of engine issues. The higher the detergent level in a particular brand of oil, the quicker it turns black. Dirty colored oil is really an indication that the oil is doing its job of cleaning and lubricating your engine. It it is not running properly, you are probably getting excess unburned fuel and other emission deposits in the engine that the oil is trying to clean up. Look at the plugs to determine whether it is running too rich or lean etc. Tuning the engine up to peak performance will help the oil run cleaner. It also never hurts to do an oil analysis. this would give you an idea of engine wear, contaminants in the oil etc. They usually fur about $15. so it is a cheap snapshot of engine health.