Q: Excessive blue smoke

asked by on

Car failed test on emissions last week. Was told the cat is gone for a new 1 fitted today and about an hour later car started smoking thigh blue smoke.. car is well serviced and maintained.. never blew smoke before.. I put in an oil additive and ran it for 2 hours with no change.. any suggestions

My car has 99500 miles.
My car has a manual transmission.

Blue smoke coming from the exhaust generally means that the motor is burning the engine oil. This can happen for a couple of different reasons such as worn piston rings or leaking valve guide seals. When this happens, the engine oil is burned in the combustion chamber along with the fuel which is what generates the blue smoke coming from the exhaust. I would recommend having an expert from YourMechanic come to your location to inspect your car’s running condition to determine what may be causing the blue smoke coming from your exhaust.

Was this answer helpful?
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
  1. Home
  2. Questions
  3. Excessive blue smoke

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: Brake pedal has no resistance

This is a very dangerous situation as the braking system is one of the most important safety features of a vehicle. Have a brake inspection carried out by a qualified technician such as the ones here at YourMechanic to look...

Q: I've been told I have leaking valves. Burning rubber smell, no external leaks but dripping noises, car not overheating

Hi there. It sounds like the valve cover gaskets are what is leaking. The gasket is made of rubber and can become hard and brittle over time and start leaking oil. The leak may not be one where it is...

Q: Car has smoke damage

Whether we are dealing with the interior being damaged with cigarette smoke or if the Mustang you are driving was subject to another form of fire, I would highly recommend locating a specialist that can deal with smoke damage. If...

Related articles

P0052 OBD-II Trouble Code: HO2S Heater Control Circuit High (Bank 2 Sensor 1)
P0052 code definition HO2S Heater Control Circuit High (Bank 2 Sensor 1) What the...
How to Avoid Back Pain in a Car
If you have back problems, sitting in a car for an extended period of time can be excruciating. Even without back problems, you could experience discomfort and soreness from...
What are the Car Pool Rules in Hawaii?
Hawaii is widely regarded as a land of vacation and relaxation, and as such, its scenic roads and routes are far better known than the state’s freeways. But, as with all...