Diesel Engines Don't Have To Smoke
Although diesel engines emit some smoke on acceleration, they should not smoke constantly. All vehicles, including diesels, are subject to the same smoking law as gasoline engines.
Prevention Is Key
While it is normal for smoke to appear during the first few seconds after engine startup only, a well-maintained vehicle should not emit visible exhaust. Preventing a vehicle from smoking often involves simple maintenance procedures.
Gasoline Engines |
Visible Sign |
Diagnosis |
Probable Causes |
White |
Coolant and/or water leaking into combustion chamber |
- Bad head gasket (leaking)
- Cracked block or cylinder head
|
Blue |
Engine oil being burned |
- Oil leaking into combustion chamber
- Worn piston rings, valves or cylinders
- Bad exhaust manifold
- Bad head gasket
|
Black or Gray |
Incomplete fuel combustion |
- Clogged air filter
- Carburetor, choke, fuel injection, or emission system malfunction
- Ignition timing off
- Blocked manifold
- Low compression due to engine wear
|
Diesel Engines |
Visible Sign |
Diagnosis |
Probable Causes |
White |
Improper air/fuel mixture. Fuel is not burning |
- Faulty fuel injection system
- Incorrect fuel injection and valve timing
- Engine overheating
- Faulty fuel pump and/or injection pump
|
Blue |
Engine oil being burned or atomized |
- Engine oil level too high
- Worn piston rings, valves, or cylinders
|
Black or Gray |
Incomplete fuel combustion |
- Damaged air filter
- Faulty fuel injection system
- Clogged air filter
- Wrong grade of fuel
- Incorrect fuel injection pump timing
- Engine overheating
- Low compression ratio
|
Report Smoking Vehicles!
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