Q: Engine knocks, tailpipe blows white smoke

asked by on

When I turn the engine on, the tailpipe blows white smoke out. The car is also shuddering. After I turn the engine off, it starts making a knocking noise. Is my engine going out or is it something else causing this?

Hello. There are a few things that can cause this. If the smoke is white then you may have a blown head gasket. This is a common failure on this vehicle, especially if it has ever overheated. If the smoke has a blue cast to it then it may have leaking valve stems seals.

I usually start by doing a compression test to see if there is an internal issue. If there is a compression problem then it is a head gasket problem. If the compression is fine then it will need new valve stem seals. Both cases will require some serious engine work be performed.

If you need to have this looked at, consider YourMechanic, as a certified mechanic can come to you home or office to diagnose the smoke and repair this.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1,000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Ask a Mechanic
(100% Free)

Have a car question? Get free advice from our top-rated mechanics.

Ask A Mechanic
Over 10,000 questions answered!
  1. Home
  2. Questions
  3. Engine knocks, tailpipe blows white 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: won't move in drive

Hello. When your car has been in an accident, the impact will cause it to go into a fail safe mode. While in fail safe mode, the car may come on but you will be unable to drive. This is...

Q: After putting new tires on my 2010 128i convertible there is a noticeable shake in the steering wheel. Tires have been balanced a

Unless severely warped, brake rotors will rarely cause a vibration when the brakes are not applied so I wouldn't thing they would be the cause of your issue. I would lean towards the tires and/or wheels. Even if a tire/wheel...

Q: Need new spark plugs and coils too early

You stated that your vehicle is a four cylinder engine, I'm confused as to why you are replacing six spark plugs? To answer the question of "Will it happen again?". It most likely will. If three out of the four...

Related articles

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...
How Much Does a Mechanic Make in Vermont?
Automotive technician jobs in Vermont have an average mechanic salary of $37k, with some mechanics earning a salary of $53k.