Oil is pitch black

[rubi]

I had just changed it like a month ago, it was supposed to be changed in 2000 kms, and it just made 750 km and it's really liquid. I had experienced once a tiny explosion in my exhaust when I was starting the car one day, and now it's a little blackish(normal sicne the oil is all black), clear most of the time, but sometimes it comes out heavier than usual. What brought my attention to that was the fact that the car is 10 degrees hotter than usual which by the mechanic's book not a big deal since it's really hot these days. The car is great otherwise...What would be the cause of that?

[AHTOXA]

Well, oil will get dark rather fast, usually within a few hundred miles. You said it's been 750 kms, so it makes sense.

Exhaust pipe is normally black as well. I'm assuming that this is what you are asking - not entirely sure. If you see smoke, then see what color it is. Blue smoke from the exhaust means you're burning oil. Black smoke means the car is running rich. Running rich condition occurs when the engine too much gas for the given amount of air, thus it's not burned efficiently and entirely.

[Rope-Pusher]

I used to run some oil with graphite in it. Dyno tests showed immediate power gain due to lower friction. I got tired of what a mess it was - any drip during an oil & filter change stained the driveway. Always looked dirty.

[comingbackdown]

I used to run some oil with graphite in it. Dyno tests showed immediate power gain due to lower friction. I got tired of what a mess it was - any drip during an oil & filter change stained the driveway. Always looked dirty.

Seriously?

[Rope-Pusher]

Yeah - Arco Graphite. Buddy of mine saw dyno run at his shop and told me about it, so I tried it. Sounds like a good idea, but a 2% gain is not discernable to the driver. Need 15 - 20% to make the change worthwhile (unless you're dyno-racing), so I stopped running it. You can argue that 2% HP gain means __% less friction / wear, but it could be less friction in some high-friction area like cam followers, which aren't my durability concern compared to rings or main bearings.

[rubi]

The exhaust isn't that black and it isn't blue, I had a minor freak out that I blew something when the water in the radiator went missing fast but apparently there were air in the system, so I kept adding water every day and things got quite balanced later, changed my filter and oil, it's still black but there is too much dirt, cause I've gone long without changing oil filters...

Thank you...

[Rope-Pusher]

If you had warped the head or the block due to overheating, and/or the headgasket wasn't sealing, signs would be excessive white steam (well, it's not really steam, since steam is transparent, but condensation from what used to be steam) coming out the tail pipe or engine oil looking like chocolate milk coating the dipstick.

[rubi]

Oil is good, it's good but blackish but nothing like chocolate milk, I had a big leak in the coolant system but we discovered a couple of holes so that was why, also my radiator cap isn't tight, it needs replacement.

But then the exhaust had gone white, and what puzzles me is that the car had no overheating problem eversince we fixed the water thing and there are no bubbles, it's also running perfectly 37.282 mph in second gear at less than 3k rpm in no time and without dumping the gas pedal to the floor, or even push it's an accelerating monster, the car is 1360cc.

Back to the question, what are the other symptoms to conclude that my head gasket is gone? Or this is it?

[Rope-Pusher]

Oil is good, it's good but blackish but nothing like chocolate milk, I had a big leak in the coolant system but we discovered a couple of holes so that was why, also my radiator cap isn't tight, it needs replacement.

But then the exhaust had gone white, and what puzzles me is that the car had no overheating problem eversince we fixed the water thing and there are no bubbles, it's also running perfectly 37.282 mph in second gear at less than 3k rpm in no time and without dumping the gas pedal to the floor, or even push it's an accelerating monster, the car is 1360cc.

Back to the question, what are the other symptoms to conclude that my head gasket is gone? Or this is it?

White exhaust is usually water vapor. It should go away after a few minutes of running (longer in colder weather). If it there continuously, I would think it means that water is running out the exhaust. If this isn't from a head gasket leak, it could be from something else. I had a friend that paid to have new head gaskets installed and the white smoke was still there. They found a coolant temperature sensor controlling engine vacuum to the distributor was leaking. Engine vacuum was sucking coolant through the temperature sensor and into the intake manifold. Is your intake manifold sucking in coolant? Is the manifold heated by coolant? If so, there may be a way that the intake manifold gasket is leaving a path for coolant to get sucked in. Exhaust all the cheap and easy possibilities before you replace the head gasket.

[theholycow]

I had a friend that paid to have new head gaskets installed and the white smoke was still there.

Would a compression test have told him that his head gaskets were fine, preventing him from wasting the money/effort on that job?

[Rope-Pusher]

I had a friend that paid to have new head gaskets installed and the white smoke was still there.

Would a compression test have told him that his head gaskets were fine, preventing him from wasting the money/effort on that job?

Maybe, but that's not the worst part of the experience. He walked away trying to think positively about it. "Well, at least the head gaskets won't be a problem for a long time now." The car got totaled in a collision a few months later. That fits my theory that the worms always come out after it rains.

[rubi]

Yeah well the mechanic suggested he needs to take the engine apart to understand what's wrong, and I was more than willing to chop his head off, yesterday the car stopped fuming white and the engine started to make some loud clicks, i donno what's the thing is called in English, but it needs tuning, and the spark plugs definitely must be changed, i need to change my water cap too, so i need to fix the small issues first i guess, and probably it'll be just fine, I've noticed no white smoke coming from under the hood either, so i guess it's not in the chambers, right?

We didn't do a compression test yet, but there are no symptoms really, but then again yesterday the exhaust just went black...

Thank you guys...

[Rope-Pusher]

^ May I help chop his head off?
There are a number of checks that could be performed rather than disassembling the motor.
Compression test, Cooling system pressure leak-down test and
spark timing come to mind.
Installing new spark plugs is a good idea, as is checking the rest of the ignition system components - engine that is misfiring adds strain to the cooling system, produces exhaust smoke, etc. Does this have a distributor? If so, check cap and rotor. If plug wires are bad, they will usually give most problem when weather is wet, but can be bad enough to produce mis-fire even when dry.
Hoping that it is something simple and cheap, but I'm not holding my breath on that.

[wannabe]

^ May I help chop his head off?

you get a trip to egypt out of it....

[Rope-Pusher]

^ May I help chop his head off?

you get a trip to egypt out of it....

Hey, I lived thru the era of Steve Martin's King Tut and the Bangles "Walk with an erection", so I can fit right in if need be.