i have a 91 honda accord, with a slightly modified f22a1 engine with 140k on it. i change my oil( always with a top brand high mileage oil) every 3 months and i noticed that my oil is a dark black every time. Last time i changed my oil i used castrol high mileage and added Seafoam to the crank case and, after just one month, i noticed it started to darken already. I'm trying to save this engine and keep it running through college, is there anything i can do?

the engine doesnt smoke, but burns a little oil.

 

seafoams job is to take those deposits and place them in your oil so that they can be burned. You use seafoam just BEFORE an oil change not after it

 

One thing to consider, a good engine oil will get dark after awhile, certainly before 3k miles or 3 months. But this is not a bad thing! The cleaners and detergents in the good oil will suspend the crud and by-products of combustion in the oil instead of letting it sludge up the interior of your engine. This suspending also carries the crap out of your engine when you drain the oil for an oil change.

I second using something like sea foam right before an oil change, and make sure your engine is nice and hot before you change the oil. Hot oil will carry out more sludge when you drain it.

Have you done a compression check? If that checks out, your timing belt is good, and you keep all the regular maintenance up on the engine, you can expect it to easily go over 200K

sohc