Oil burning and turning black early

[robscards]

I've recently bought a 1986 Dlx 4wd auto. Runs great. 135k miles. Checked oil and was down 1.5 quarts and black, so I changed it, and it was clean when I checked it after a quick drive. 90 miles later it was down 1/3 and black. I ordered a exhaust manifold to have installed, cause it had a slight leak/crack, and I thought his might have helped cause the problem. Part in route and not installed yet. Car has no oil leaks when parked. Any reasons why oil may be premature black and using so much?

[irowiki]

I don't think the exhaust manifold would cause this.

Stuck piston rings most likely. I have the same problem with mine, but worse. About a quart every 100-200 miles. You can try seafoam in the oil, "Restore", ATF in the oil, seafoam in the spark plug holes, and I've done more while trying to fix it!

Did the wagon sit for a while?

[robscards]

Thanks for the response. I don't think it sat completely undriven, but probably was driven infrequently for quite a while. No blue smoke comes from the muffler. Will it driving it make the issue less prevelant?

[irowiki]

In my case nope, driving hasn't helped at all. I'm about to do a motor medic flush then put 3 quarts of ATF in her and see if that helps.

The wagon in question sat for 5 years or so only being driven once a week if even.

It was thought valve stem seals would fix it, but it did not.

Other ideas were:

bad piston rings
clogged PCV valve
bad valve stem guides

PCV valve is an easy fix.

Usually the higher sustained RPM's, the more it eats the oil. No noticeable blue smoke out of mine either.

I even tried diesel oil to no avail!

Check this thread for my saga:

https://tercel4wd.com/forums/viewtopic.php?f=4&t=9504

[marlinh]

Infrequent oil changes would cause new oil to blacken quickly. If you do several changes at shorter intervals, it will help with the colour of the oil. Oil control rings would be gummed up as well. Seafoam is worth a shot.

[keith]

"it was down 1/3 and black" Do you mean down 1/3 qt or 1/3 of the oil in the sump (a little more than a quart down)?

[teranfirbt]

Try changing to delo400 (diesel) oil for a bit and see if that improves things. Diesel engine oil has more detergents than gasoline engine oil, so will clean out rings and such better. I've seen an improvement in consumption (1 quart every 500 miles to 1 quart every 1500) and blow by (oil black by 1500 miles to oil black at 3000) on mine by running ~3000 miles on 2 changes (1500 miles each) of diesel engine oil.

[irowiki]

I tried Diesel oil (Delo400) too, hasn't helped yet, probably will change the oil soon and put diesel oil back in it just in case.

[robscards]

I meant it was down 1/3 quart.

[robscards]

Actually, the car is not burning oil. The oil that was down over a quart was the same oil car had in it when I bought it, so it might have had moisture in it. When I checked it and it was 1/3 qt down, it was on a slight incline. I didn't think it would bother it that much, but I guess I was wrong. I have since checked it and after 200 miles dip stick still full. Rookie mistake, I guess.