Monday, January 18, 2010

Blue Smoke from Engine's Exhaust

Blue Smoke from Engine's Exhaust

Many people consider blue smoke from a vehicle to be elusive. Blue smoke is generally caused because of several specific conditions in the vehicle's engine. We will help you determine what the problem is so it can be corrected and stop the blue smoke. Blue smoke appears mostly at morning start up because oil from the vehicle's engine is mixing with the gas inside the engine's combustion chambers, then burned together with the fuel from the injectors while the engine is running. This can result in a very expensive repair, but not always. The more expensive and usually terminal reason for blue smoke is the piston rings have worn out allowing engine oil to pass into the combustion chamber.

In this case the engine is worn out and needs to be replaced, this can be expensive. There are other reasons the engine can burn oil, some engines have a small oil drain back holes in the cylinder heads, these holes allow the engine oil to drain back into the oil pan. The oil is picked up by the oil pump and returned back to the engines vital parts under pressure. If these drain back holes become plugged it can cause oil to seep down into the valves and into the combustion chamber. To repair this problem remove the valve cover and clean debris from the drain back holes, reassemble and recheck (note: after repair you must wait 2 to 4 days before the remainder of oil on the valve stems to be removed)

Most of the time producing blue smoke can be repeated since it's not usually a problem that is a single occurrence. Typically, once a vehicle starts producing blue smoke this pattern will continue to repeat until the engine is repaired. There are times when some engine additives can cause the blue smoke as well. If you are continuously adding additives to your fuel to stop smoke, you may be inadvertently covering up the smoke that your vehicle produces normally. However, if you are continuously adding engine or fuel line cleaners that are a strange color it can on occasion produce the strange colors of smoke. This condition is normal and will subside when the cleaner has run its course.

Common Problems and Solutions

The most common problems of blue smoke revolve around oil leaking into the engine's combustion chambers and burning with the fuel as discussed. However, the solutions to the problem often vary depending on the exact condition of the engine. There are times when the correction can be as simple as changing the valve stem seals or cleaning drain back holes.

It is important to note that if you decide to repair the engine you have, you are often looking at hourly repair rates plus parts and machine work to repair the engine. This is quite costly and depending on the age of the engine may well not be worth the expense of the repair. If you are highly fond of the vehicle and intend to keep it there are definitely times when a new or rebuilt engine is a better deal. Keep in mind, if you decide to change out the engine you are often able to extend the life of your vehicle by 10 years or more which can save thousands over the price of buying a new vehicle. Plus, your best bet on a new or rebuilt engine can be obtained by the dealer; surprisingly the dealer cost for the engine is close to what you will pay to have the engine rebuilt independently.


Maintenance for a vehicle is something that is often overlooked. From blank stares when asked when the last oil change occurred, to the even stranger looks that occur when asking when the last tire rotation was completed. It is very important to maintain oil changes and tune-ups that are performed on schedule. Proper maintenance to your car is a good way to keep all internal engine parts from becoming damaged prematurely. Without oil lubrication an engine will quickly become severely damaged. Anytime you are able to lengthen the life of the engine and help avoid breakdowns it is beneficial to the motoring experience.

Sometimes it is advisable to seek a professional ASE or other certified mechanic to trouble shoot the problem for the blue smoke condition. Never avoid engine problems as they can cause a simple and inexpensive repair to escalate to a costly repair that could have been avoided. Choosing the right mechanic or repair shop for your needs is often the biggest issue, however many times it can take just a referral from a friend or relative in order to find an appropriate repair shop.

Poorly maintained engines are much more prone to problems such as smoking. The excessive friction leads to catastrophic engine failure. Preventative maintenance is cheap insurance to ensure that your vehicle runs as smooth as possible for many miles to come.


  1. Mean the blue smoke is cause by did not maintan it accordingly?

  2. I am confused whether blue smoke is good or bad?
    What should we do when we have blue smoke in our vehicles? Sometimes even my vehicles throw out blue smoke?
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  3. @Centenial College: Do you mean when you start your car early in the and there's blue smoke coming out. Don't worry about that. That's normal for the starting. It's just some cold air when the engine is not warmed up. Blue smoke is not good for our car for sure bro because it might be the cause of ur engine oil is leaking between the area and that's not good for sure.

  4. Excellent read. I like your style...have a good one!/Nice blog! Keep it up! Exhaust Repair