ArmyofOne

Different color smoke is indicative of different kinds of problems in your engine. There are 4 colors of "smoke" you might see from your exhaust. The list of color’s and their meanings, is as follows:

1. Steam: Steam is normal, it is important to understand this. If it is cold outside, your car exhaust is more than likely spewing steam, not white smoke. You will be able to tell the difference, trust me. If the car were smoking, it would smell horribly wrong.

2. White Smoke: White smoke is typically indicative of coolant being burned in the combustion chamber. There are really only a few ways this can happen, and none of them are good. They are;

• A cracked/warped cylinder head.
  
• A blown head gasket.
  
• A cracked engine block.

In any case, either a partial or full engine tear down and rebuild is in your immediate future. A cracked cylinder head or block can be caused by overheating, dumping cold water on a hot engine that is not running (and at operating temperature), or simply by metal fatigue over time/miles. The last one though, is quite rare. Most of the time when your block or head is cracked, its because the engine was overheated recently. When this will lead to coolant burning or white smoke, is if your head is cracked in between the cooling passages and the combustion chamber, which will allow coolant into the chamber to be burned.

IMPORTANT NOTE: White smoke can also be caused by a stuck fuel injector causing cylinder washout. This is one of the exceptions to the rule. This is (again) a very serious problem that needs to be taken care of immediately.

• A “warped” cylinder head causes a leak in the cooling passages (or water jacket’s) between the head and the block. This causes coolant to leak past the head gasket, into your combustion chamber. Hence the white smoke. A warped head can sometimes be corrected with a milling machine, checked and re-checked to make sure the gasket surface the head gasket sits on is perfectly level and flat…but this is often as expensive as a new cylinder head, and only works about half of the time.
  
  
• A blown head gasket happens when the gasket between the cylinder head and engine block cracks or fails. This gasket is usually made of pressed metal, and can, over time and repeated heating cycles, fail. When this happens, the waterpump pumps coolant through the engine like normal, but there is no longer a complete gasket in place to keep the coolant separate from the oil and combustion chamber. More often than not, this results in oil the color and consistency of mud, and white smoke.
  
  
• Lastly, a cracked engine block can cause white smoke by allowing coolant to flow into the combustion chamber through small cracks between the water jacket’s and the cylinder walls. Keep in mind, all “cracks mentioned in this thread will be less than the thickness of a human fingernail, they can be tough to spot.

3. Blue smoke: Blue smoke is usually indicative of oil burning in your combustion chamber. This usually has 3 primary causes;

• Spark Plug O-Rings- To put it simply, this is the cheapest (and therefore the best) option of the 3. If this is where your smoke is coming from, simply pull the spark plugs, wires and valve cover(s) and replace your o-ring seals. However, I would HIGHLY recommend a compression test to make sure either your valve seals or piston rings are not bad.
  
  
• Valve seals- If you have blue smoke only on startup, or while your engine Is cold, you very likely have some valve seals that need replacing. This requires the head to be removed, but the work is not too terribly difficult. If it is more than you think you can handle, expect it to run $1,000-$1,500 at a shop to diagnose and repair. If it turns out your valve seals ARE bad, replace them all (on that side of the motor), do not just replace the bad ones, because surely if one or two went, the others will shortly follow (Murphy’s law).
  
  
• Piston rings- If you do a compression test, and your compression is not within spec, this could be the culprit. Piston rings are metal rings that are in place around your piston. They keep your piston from contacting the cylinder walls, as well as serve as a seal to keep oil from entering the combustion chamber. As the piston comes up the cylinder, the rings contract, and apply the oil to the walls of the cylinder, lubing the walls. On the down stroke, the rings expand, act like a squeegee and sqeeze most of the oil off of the cylinder walls so it does not burn. If you have blue smoke while your engine is running, constantly, or even just under acceleration after it is warm, one or more of your piston rings is probably bad, and is allowing oil past it, into the combustion chamber where it can be burned. The solution for this is unfortunately, expensive. Some cars can be done cheaper than others, but on average a ring job in the industry runs about the same as an engine rebuild. Figure on a minimum of $2,000 in labor, and up to $500 in parts depending on how bad things have gotten. The longer you let it go, the more damage can be done. If one of the metal piston rings has flipped or warped and it scratches the cylinder wall, you may have to buy an entirely new (or used) engine.

4. Black Smoke: Excess fuel in the system is usually the primary cause for black smoke (“Running Rich”. The causes for this range from faulty sensors, faulty fuel pressure regulators, faulty injectors, or even faulty fuel pumps. But rest assured if your engine is spitting black smoke, there is more than likely a problem in the fuel system. Keep in mind that the fuel system and the air system (Intake) work together. If your engine is not getting enough air, it could produce symptoms of a rich condition, when really all you need to do is change your air filter. The smoke is caused when there is either not enough air in the mixture, or too much fuel in the mixture. Either way, it spells trouble for your engine and you should have it diagnosed and fixed as soon as possible.

jupa28

im running black all times.....

mikecu

Did you fix it? What was the issue?

ohiois350

iTrader: (13)

after I had a leak right before the calyat convertor and had black smoke came out after changs that no more black smoke 02 highlander

2move

Here looks like a solution for it:

Video at uTube

slideland

What kinda car are you Driving year, and model jupa28

acl99

iTrader: (2)

I have a 93 sc300 5spd, and it seems like the black smoke will never stop. I've changed the plugs, cleaned the injectors, replaced air and fuel filter, oil change, etc. Still has a tinge of black smoke during acceleration? Any ideas??

mitsuguy

iTrader: (2)

Just a little is actually perfectly normal...

Every car should run rich when at wide open throttle...

2move

by reading all the cases, -
here is

one universal solution

,
that helps in a lot of the cases...

lobond123

Dear teachers,

1) When a car is producing BLACK smoke or WHITE smoke. Is there any connection to do with with the Diesel engine or Petrol engine? Or Diesel engine will produce Black smoke? Petrol engine will produce White smoke? Or producing Black or White smoke is nothing to do with the Diesel or Petrol Engines.

Thank you

lobond123

mitsuguy

iTrader: (2)

Diesel is a whole 'nother story....

Lots of black smoke in a diesel is from overfueling - on older diesel engines, this was about the only way to make a bunch of power... With newer diesel engines, this isn't nearly as true... White smoke in a diesel means it is running lean, which may also be perfect when it comes to a properly tuned diesel... (more grey than anything is perfect)

lobond123

Dear teachers,

Thank you for answering my question.

That means Diesel engine can produce BLACK or WHITE smoke and Petrol engine also can produce Black or White smoke. Am I right? Please clarify.

Thank you.

lobond123.

mitsuguy

iTrader: (2)

Correct, either engine can produce either color smoke...

lobond123

Dear Mitsuguy,

Thank you for teaching me this knowledge, I am a new member here, I am very happy to join this club Lexus.

From : lobond123.

dc893

If you have an old LS blue smoke can be caused by a leaking power steering air control valve. The power steering fluid gets sucked into the intake and gets burned up in the engine causing it to smoke.