black water blues

[jkeyzer]

I just drained my oil (72 2.4T with MFI) and I am somewhat concerned. It was last changed (by me) less than 5000 miles ago. I should have paid more attention last time, it was probably pretty much the same condition as it is right now.

It seems thin. Not quite as thin as water, but much thinner than new oil. I can slosh it around in a glass jar about as easily as water, though, and it runs off of a wrench pretty quickly. It's still slippery between my fingers. It is also pitch black and stinks - hard to place the smell. Not quite like gasoline but along those lines.

Is there anything other than a MFI pump leaking gas into the oil that could cause this? It's hard for me to say that this oil is unacceptable and the pump needs overhauled immediately, or if this is just an old car running rich and dirtying up its oil. What criteria can I use to decide?

I am thinking of taking a sample to my local mechanic and seeing what he thinks, but I would tend to think he would be biased towards a complete overhaul at my expense!

The question in my mind - Am I destroying my car by driving it on black water??

[Bill Douglas]

I have heard MFI can leak gas into your oil, so I suspect this is what your problem is. Maybe do some work on the MFI...

[Bobboloo]

I woulden't run the car until you solve this as it is sure to ruin the motor.

When you drained the oil for the last oil change did you also drain the oil tank?

Could you be running to rich?

Is the thermostat functioning properly?

After you rectify the problem (probably the pump) do a compression test to find out the condition of the motor.

Good Luck
Bobby

[dickster]

don't know much about mfi, but if it were that colour last time round i would do a few quick changes, say at 500 or 1000 miles, until the stuff being drained is pretty fresh looking in colour.

[jkeyzer]

I did a compression test a few weeks ago and everything looked ok. I have a feeling that this condition has existed since before I bought the car. I'm just not sure how severe it is - I haven't seen "bad oil" before so I'm not sure if I am jumping to conclusions with this or not.

I have never noticed the oil level rise on the dipstick before, but at the same time it doesn't seem to drop very much either. I can drive it thousands of miles without adding a quart, which seems a bit "optimistic" for how much this engine leaks (and might burn also, though the plugs look fine.) I've heard if the level rises, you're screwed!

One last note is that I do think I was running rich for a while as I used to make plugs go black. I guess what I am wondering is if I have gas in the oil, will it be obvious?

[dickster]

no experience, but i would think you'd be able to smell it?

would the oil be dark in colour straight away if you changed the oil? i would flush some cheap oil through it for a few quick changes and see if you still got a problem. change the oil run it round the block, see if its black, if it is change it again. should go unless severe problemo.

[Superman]

I too have heard that MFI systems put gasoline into the oil. Over time this dilutes the oil. If this is true, then the remedy would be to change the oil frequently.

[Early_S_Man]

Jeff,

I believe that your 5K change interval is a bit longer than ideal!

If you stil have the oil you drained out, I would suggest pouring into cleaned/rinsed out liquid laundry detergent jugs of the 200 oz or 300 oz siZe for temporary storage until a few issues get answers! I suggest examining the bottom of the drain container for metal particles or shavings ... such as copper and lead from the rod bearings, and iron from rings or cylinders!

You probably should send a sample to an oil analysis service, and be sure to send some swabbings from the bottom of the drain pan that have settled out! I don't think you should run your engine until you get the oil analysis results back.

If there is no indication of rod-bearing material in the oil, I think it will be safe to drive you car with fresh 20W-50 conventional oil ... but, I think you should keep close tabs on the status of the oil for the forseeable future, on a weekly basis, for gasoline contamination on the dipstick. if the contamination continues, I believe you should change the oil at a minimum of three-month intervals, or as soon as any thinning is evident. You may want to get a drip gauge for checking the viscosity of paint.

Is there any possibility your cold-start solenoid was stuck on in the recent past? The injection pump isn't the only potential source of gas contamination! And, your extended 5K shange interval may be the primary reason for the thinning, considering the relatively cool climate you are in , and short trips where the oil temperature never reaches normal levels ... the warm-up cycle is a major contributor to fuel washing of oil from cylinders! Good luck!

[jkeyzer]

Warren -

The cold start solenoid was deactivated until I brought it back to life a few weeks ago. It seems to work fine and I have never noticed it being stuck on.

I do take the car on short trips sometimes but just as much I will take it on long extended drives especially on the weekends. During those periods it often sees temps close to 100C in this weather.

I admit it was probably too long since my last oil change and that is going to make this problem worse. I still have the oil I drained out so I am going to see what I can do with it. I'm planning on changing the oil again soon to see what it looks like when it comes out. Can anyone suggest an oil analysis company? I've heard a couple URLs mentioned in the past and I'll have to go find them. I rubbed my fingers in the oil and didn't notice anything strange floating around in it.

I am also thinking about buying a backup MFI pump to try and see if the problem gets any better or worse. At the very least I could keep the car drivable while I have my old pump rebuilt - if I choose to go that route.