Mechanics

Exhaust Pipe Smoke - Blue

Easy step by step repair guide on how to troubleshoot and repair blue smoke from the vehicles tail pipe, each step is presented in the order of popularity, this article pertains to most cars.

Difficulty Scale: 5 of 10

Tools and Supplies Needed

  • Flashlight
  • Socket set
  • Wrench Set
  • Screw Driver Set
  • Protective eyewear and clothing
Before beginning, park the car on level ground with the parking brake set.


Blue Smoke from Exhaust Tail Pipe

Step 1 - Sludge can develop inside the engine due to poor maintenance and can plug the oil drain back ports which in turn fills the cylinder head up with oil which then gets fed down through the valve stem seals and into the combustion chamber producing blue smoke. To repair this problem remove the valve cover and clean debris from the drain back holes, reassemble and recheck (Note: After the repair you must wait 2 to 4 days before the remainder of oil on the valve stems to dissipate.)


Engine Sludge

Step 2 - All engines are designed with some kind of internal ventilation system which controls vapors inside the crankcase, if a hose becomes loose, plugged or a diaphragm fails it can cause the engine to ingest oil into the combustion chamber which produces blue smoke.


Crankcase Vent Control System

Step 3 - As an engine wears, the piston rings will lose their ability to control oil which will allow it into the combustion chamber to be burnt causing blue smoke from the tailpipe, in this case the engine is worn out and replacement is needed. To confirm this diagnosis remove all spark plugs and inspect, if all plugs have oil on them the confirmation has been achieved, if a single plug is fouled then only one cylinder needs to be fixed. Visit - Piston ring replacement


New Piston Rings

Step 4 - Valve stem seals control oil from entering the combustion chamber, if these seals wear out blue smoke will result due to oil entering the combustion chamber, to repair this problem replacing the valve stem seals is necessary.

Helpful Information

Blue smoke appears mostly at morning start up's. Poorly maintained engines are much more prone to problems such as smoking, preventative maintenance is cheap insurance to ensure that your engine runs as smooth as possible for many miles. If engine replacement is required the best option on a new or rebuilt engine maybe obtained by the dealer, surprisingly costs for the engine (engine only, no labor) is close to what an engine rebuild can cost independently.

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