Mechanics

Excessive Smoke From Exhaust Pipe

Excessive Smoke from Engine Exhaust Tailpipe
How to Repair Excessive Smoke from the Exhaust Pipe

A small amount of smoke from the exhaust pipe of the car is normal. Excessive smoke is created by a malfunction. The smoke is cause by excessive fuel or engine oil. If this condition is allowed to continue it can affect the exhaust system. Failures can range from catalytic converter becoming plugged to engine overheating and poor fuel economy. Below we have listed the most common causes for this condition. 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. This 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.

Smoke that is Produced by Engine Malfunctions List Below:

Smoke from the Engine Exhaust System

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.

If further assistance is needed, our certified car repair technicians are ready to answer your car questions.

Related Car Repair Information

AUTHOR


Written by
Co-Founder and CEO of 2CarPros.com
35 years in the automotive repair field, ASE Master Technician, Advanced Electrical and Mechanical Theory.


COMMENTS TO THIS ARTICLE


Please use our question form if you have a specific question about your car as we are not able to give you a full answer on this page.



Article first published (Updated 2013-08-16)