oil issue

[AllisMitchChalmers]

After about 2000 miles...my oil is PITCH BLACK!! What is causing this?

[freyguy_412]

What type of oil are you using? I had that problem with penzoil (stupid wax based sewer sluge). I have sense switched to castrol gtx and I'm still having the problem but it has gotten better.

One thing I havent gotten around to trying is a makeshift engine flush. Buy enough oil and filters for two oil changes. Drain the oil, replace filter, and fill with a better quality oil. Run it for ten minutes to get this oil well circulated and such, then drain the new oil and replace the filter again. Fill with more fresh oil and see what happens.

[mitmaks]

ya flush might help, but be careful on high mileage engines big chunks can clog up pick up screen etc, i would remove pan and clean it all inside, then switch to synthetic and good quality filter, ie bosch, napa gold, k&n or mobil 1

[neutral]

After about 2000 miles...my oil is PITCH BLACK!! What is causing this?

Short answer... dirty engine.

1. How many miles on the engine?

2. How many miles on it when you got the car?

3. Any records from the previous owner on oil/filter change intervals and oil type used?

4. Have you recently began using a synthetic? Synth put into a dirty engine that has always run on dino oil (especially if oil/filter changes were neglected) can cause your new oil to get dirty as the synth loosens dirt/sludge/carbon deposits.

5. Open the oil filler cap. Is the backside of the cap dirty and sludged?

6. Shine a flashlight into the oil filler opening. You'll get a partial view of any sludgy buildup or brown stained internal surfaces indicating that maybe the previous owner wasn't attentive to frequent oil changes.

7. Try changing the oil/filter at 2K miles or whenever you see the oil getting discolored. This can help accelerate removal of built up contaminants without the danger of a chem flush which, on a high mlieage dirty engine, can cause main-bearing-destroying sludge and deposits to break loose ond fall into the crankshaft bearings. Try the frequent changes for several change-intervals and see if your oil doesn't start lasting longer between changes.

[AllisMitchChalmers]

The engine has 79k on it. It had 63k on it when I bought it. *cough* I was the guy a while back pissed off because I got a sorry a-- MX-3 with very shitty gas mileage and a slow automatic. I have been running Havoline in it and using Fram oil filters. It did sit in a lot for about 3 years and wasnt cranked up really. I really dont know the story on this car. I am the fourth owner. I old man bought it new, then a college girl bought it (and ran it into a ditch and fucked up the rack and pinion), then my friend bought it real cheap and stuck it at his job where it sat for 3 years. He was going to put the new R&P in but never got around to it and I bought it for 500 bones plus some work I did on his house.

Maybe the period it sat caused it to get gunky and stuff. It is also starting to burn oil...not much...but a little bit. I am thinking that either some gunk has starved the engine of oil or the valve rings are dried out or something.

[neutral]

Then due to such a long period of sitting, I'd be inclined to remove the oil pan and clean it out. No telling WHAT might have precipitated and coagulated on the bottom of the pan during 3 years.

[LongJohn]

I agree with the frequent oil change idea. I've decided I like high-flow filters more than better-filtration filters. A high-flow filter will still catch all that crap you see. High flow also means the filter drops less pressure which means your hydrolic lifters have better oil pressure and flow which makes the perform better.

There is a site somewhere from Bob the oil guy. Search for him (I forgot the url) and read up a bit. Don't use any of those crappy additives either, just keep freshly changed oil in there.

Dropping the pan and cleaning it might also be a good idea because you will get a much better idea of just how bad it is (and a chance to clean the strainer (really bad for oil flow if it is getting blocked). This means a lot more work though.

Don't forget to change the oil when it's fairly hot (but don't burn yourself). Changing the oil cold leaves a lot of the gunk behind.

[guyaverage]

The fact that its starting to burn oil and the oil getting back quick are part of the same problem. More than likely you have worn oil control rings (piston) or worn valve guides/seals. The blowby from either will cause the oil to go dark quick (due to the contaminants in the blowby gases), which really means the oil is doing its job (keeping the crud in suspension) but the problem of the crud (carbon, etc) getting there wont cure itself without at lleast a partial rebuild.

[neutral]

Hadn't thought of that, good point. Worn piston rings would cause the prob but the engine is relatively low mileage. If the problem persists, I'd suspect hardened valve seals before the piston rings, given that the engine sat for 3 years, those rubber seals may have fossilized without regular "oil baths" from a running engine...

...More than likely you have worn oil control rings (piston) or worn valve guides/seals....

[BuGS]

BTW so you guys all know, They sell Castrol GTX at Walmart for really cheap! And the Walmart Oil filters are repackaged, I don't remember but they are a real good brand. RX7 club has researched em and found they work extremely well because they are a real good brand but Walmart sells em as Super Tech and cost like $2. Its insane...

[93SOHC]

everyone has great advice here, but I thought i'd add my .02 to the group. Allthough i'd definately reccomend doing valve seals and also dropping the pan and cleaning it out, i'd like to add a bit to the frequent oil change bit. Change your oil, drive the car for 1 week, chrange it again, repeat until when you go to change it it still looks clean. This helps get all the gunk out by cycling the oil thruogh the system. I had to do this on one of my previous cars because it was 12 years old, but only had like 48K on it, and sat a lot. I did it 5 times over 5 weeks(I worked at a shop at the time) and all was well afterward.

[AllisMitchChalmers]

Thanks guys...yall have been a big help. My alt just went bad last night so I might think about taking off the oil pan and checking things out. Can I just seal it with some black RTV silicone?

[93SOHC]

yup