Sorry if I'm beating a dead horse here, I *DID* search the archives, but wanted to ask specifically for my car:

I bought my 1994 Coupe last year, and it's been running great. No issues (knock on wood). (I'm not the original owner).

I drag race it, so I change my oil a lot more often, whenever the little 'Change Oil' light comes on. I probably change it every two months, or 2000 miles... I'm guessing the high revs of racing makes the light come on early. No biggy, I can afford dumping Mobil One in there more often to get the enjoyment of racing.

My question is: I notice that my oil is REALLY dark black when I go to change it. Since I'm changing early (not going 3000, 5000, or 7500 miles) I would imagine the oil should still be somewhat clean, but it's not.

The change oil light just came on again, (91,000 miles) and the oil is black as night again. I don't know what the previous owner put in this car, if it ever saw dino oil, or always Mobil 1, etc... so I'm debating whether or not I should do an engine flush of some sort.

From the archives, I see the following solutions:
1) Put some seafoam or marvel mystery oil in the oil, run it for 10-20 minutes, and then drain it HOT.
2) Put some seafoam or marvel in the oil for a couple days, and then change the oil, be sure to take it easy on the car while the additive is in the engine
3) Buy some GUNK Motor Flush, drain the oil, put that crap (sorry, GUNK) in, and then drain/refill with fresh oil.
4) Leave the engine the heck alone, because flushing out older / high mileage engines always ends with sadness/anger (sludge will start floating around and hurt something important, rather than lying dormant where it wasn't causing any problems).

Opinions?

 

If it ain't broke don't fix it! It runs well,your oil is doing its job,whats to fix?

 

I would suggest not to but any additive or cleaner in the oil. The marvels mystery oil is a used car dealers quick fix.

I did however use (Chem 12?), can't remember the exact name, in a Dodge truck with 250k miles. I didn't notice any difference.

 

As you said, "If it ain't broke, don't fix it."

The oil is dark because it's doing its job. It gets dark because it's removing the impurities. Just make sure you keep running synthetic and change frequently. You're doing the right thing about changing frequently due to your racing penchant. Everything sounds a - o.k.

 

First in a Miata and then in my 86 Corvette, I used Gunk as the instructions described. After doing so, the oil remains golden between changes. I was surprised. My 86's oil stays golden through regular daily driving and the ocassional track day. I assume that will change at some point but it has been about 10K so far.

 

Mobile 1 is enough to clean the engine parts. If you took your valve covers off, the rockers are probably squeaky clean.
FWIW, I change the oil every 3K miles on both Vettes and use Mobile 1, the used oil is black as tar.

BTW, here's mine with the valve covers off, about 125K miles, I use Mobile 1 only. There's no gook or residue, there is no need for additives.

 

WOT adds maximum fuel, but if it's also driver, scan it and check fuel delivery.

 

So running gunk remover or synthetic oil thru the motor may loosen sludge and it may get stuck somewhere and cause damage? I have already heard about it leaking but I don't believe that but gunk getting stuck somewhere seems within reason.

 

It would probably get stuck in the oil filter.
The original poster said he changed the oil several times with Mobile 1, so there is probably no sludge, or anything else in there.

http://www.nordicgroup.us/oil.htm#5W30%20versus%2010W30

 

If you're racing it pretty hard, you are probably experiencing a little "blow-by" which tends to turn the oil dark. Skip the additives and keep on changing the oil.

 

I agree just keep doing what your doing.Maybe try one oil change with an easy right foot and see what the oil looks like.

 

i used gunk flush on my mustang and spun a bearing a week later
it'll clear up

 

This is just my opinion... I would stay away from the Gunk engine cleaner, and probably anything similar. When I worked in parts, I never let anyone walk out with a can of that stuff. It's almost like kerosene. You never know if it's cleaning sludge that's making up for loose tolerances somewhere. I'm not really big on the other mechanics in a can.

Anytime I've wanted to flush a motor, I've always done extra oil & filter changes after a couple hundred miles. I've always assumed that if the oil was black, it was dirty, so I change around every 3K (dino). Maybe it's worth it to change your oil and keep regular notes on how soon it turns black?

 

Thanks everyone for your replies... Just finished changing the oil. No additives.

 

The black crap is carbon.If theoretically NOTHING can get past the rings then there's nothing in an engine to produce that dark colouration unless you run it so hot you overheat the oil.What you're seeing is a product of blow by. You probably have some ring wear.All the flushing in the world isn't going to alter that.

 

Okay, now that I've read through this thread, I'm concerned. Today I drained the oil followed by Purepro Professional formula MFX-128 Motor Flush for 10 minutes (engine running of course), then Mobil 1 5-30 synthetic motor oil (old filter removed, new filter for flush, new filter for oil). Am I in trouble? If so, is there anything I can do?
I also pumped out the power steering fluid and flushed with purepro PSX-32 power steering flush, pumped and added Mobil 1 ATF. Was that bad too?

 

I spend a lot of time on another forum relating to Miatas, my other passion (as I'm drawn to C4s and Miatas, I suspect I have a penchant for underrated, openly mocked even, sports cars).

A lot of the members there were recommending flushing the motor with ATF fluid, which is motor oil with a lot of detergents added to it. It's worked quite well for a lot of the people there, so I decided to give it a try about 2 years ago on my supercharged motor which, at the time, had about 150,000 miles on it.

The process, named the "2twisty flush" after the member who came up with it, is fairly simple:

1. Drain your oil
2. put on a filter, the cheaper the better, since you only need it for an hour or so
3. fill the crankcase with 1 quart of 50 weight oil and top off with ATF fluid (3-5 qts, whatever your car calls for)
4. run the car at idle for 1-2 hours, DON'T drive it, just let it idle
5. turn the car off, let it cool for 30 min or so
6. drain the oil while still warm, drain it well, for maybe another 30 min
7. (optional, but I did this) run a gallon or two of fresh kerosene through the engine, pour it in the oil fill and let it drain through...do NOT run the car this way
8. change the oil filter to your filter of choice
9. install the drain plug and fill with your oil of choice

Peeking under the valve cover before and after, I was truly amazed at how clean the engine was. My car was very well maintained, oil changes every 3-4k, etc, but before there was a little sludge and almost everything was coated with varnish. After it looked like a new engine, the heads and lifters went from yellowish brown to clean and white. More importantly, I was developing a HLA ticking that's common to Miatas; afterward it was gone.

I've since done this to a 2001 Blazer and a 1994 Explorer. The Miata now has 172k on the odometer, the Blazer's somewhere in the 140k range (daily driver, not sure exactly where it is today). The Explorer hit 250k before I sold it to a neighbor kid (4 years ago)...he's still driving it today, back and forth to college. I can't promise that it helps, but I'm convinced that it won't hurt anything.

It's cheap, easy, and no harder than doing 2 oil changes, back to back, with an extra step in the middle. I wouldn't do it every oil change, but every couple years is my routine.

 

That's interesting. I may have to give this a try.Thanks.