When the engine fails, the car will show a different phenomenon, which is one of the different noises. It is often the performance of some failures. If it is not eliminated in time, it will speed up the wear of the machine parts and even damage the accident. Therefore, it is necessary to judge in time and take the necessary maintenance measures to eliminate the failure.

Check engine noise

An artificial visual inspection method can be adopted

The 1 look: it is to observe the condition of the mechanism, assembly and parts of the fault, and judge the working condition of the engine.

2 touch: touch the temperature and vibration condition of the possible parts by hand, so as to identify the tightness of the fit, the size of the bearing clearance and the balance of the counterweight of the parts.

The 3 test: through various test methods, the fault phenomena fully revealed, such as horn, turn the ignition switch or a light switch, a spark plug off the fire, the engine speed is increased or decreased, assembly or parts when necessary can also be changed. The contrast test.

4 listen: according to the sound and sound of the engine in different conditions, different parts of the sound and sound of the law, to determine what is normal, which is abnormal.

If a two touch, three test, and four hear that the engine makes a different noise, then you need to tell what is wrong. Next, Komo collated "four listens" to teach you to easily identify the engine failure:

Remember "four listens" and easily identify engine failures

Throttle ringing

phenomenon
Diesel engine cold start the car, prone to noise.
Sound and speed has nothing to do, only occasionally appear crisp sound, will soon disappear, serious, this noise will appear frequently.
Individual cylinder does not work sound when accompanied by sound, disappeared after the return to normal.

Reason
Valve seat in the cylinder head inlaid with small amount of interference caused songkuang.
Selection of valve seat materials properly, the thermal expansion coefficient is too small.

Diagnosis and elimination
When sound appeared, accompanied by the individual cylinder does not work; the sound disappeared, diesel engine returned to normal, the diagnosis may be for the valve seat of the cylinder does not work loose.
By cylinder by cylinder pressure gauge measuring cylinder pressure, cylinder pressure for low noise cylinder.

Camshaft ring

phenomenon
Diesel engine speed, a heavy sound from one side of the cylinder camshaft speed when the sound of chaos.
Single cylinder oil, sound the same.
Camshaft bearing near with vibration.

Reason
Camshaft bearings and axle clearance is too large, loose.
Camshaft bearing looseness or bearing alloy erosion, peeling or excessive wear.
The axial clearance is too large or camshaft camshaft bending.

Diagnosis and elimination
The diesel engine in the strongest sound speed, auscultation with a stethoscope on the cylinder, if accompanied by a strong vibration sound somewhere, it can be diagnosed as the bearing ring.
Off the oil test sound change, can slowly transform solar term door, if the idle speed sound clear, sound obvious medium speed, high speed noise from the clutter becomes weakened, it can be diagnosed as axial clearance between the camshaft is too large or loose bearing.

Valve leakage

phenomenon
When the failure occurs, the diesel engine has difficulty starting up, the exhaust pipe is shot and smoked, the fuel consumption is increased, and the abnormal noise is sent out.

Reason
Valve and valve seat surface abrasion, erosion, poor sealing and leakage.
Valve and valve seat surface carbon deposition, the valve is not tightly closed and leakage.
Valve and valve clearance is too large, the valve rod shaking, resulting in the air door is not tightly closed and leakage.
Valve rod in the valve conduit astringent or stuck, the valve can not move up and down.
Valve spring elastic spring break or lose.

Diagnosis and elimination
In the exclusion of the ignition system and fuel system fault reasons, measuring cylinder pressure cannot determine the fault when measuring cylinder pressure or intake manifold vacuum, can more accurately determine the fault, measuring cylinder pressure, cylinder pressure valve leakage of cylinder is low compared to the other.

Hydraulic tappet sound

phenomenon
When the diesel engine runs, there is a sound of rhythm. It is obvious at idle speed, and the medium speed is weakened or disappearing.

Reason
Diesel engine lubricating oil page is too high or too low lubricating oil bubble into the hydraulic tappet, forming an elastic gas caused by noise.
Low lubricating oil pressure.
Lubricating oil pump, filter damaged or broken, the air sucked into the lubricating oil to.
Behind the liquid column failure.
Use inferior lubricating oil quality.

Diagnosis and elimination
Check the oil level, as the case to add or replace the oil quantity in the normal state.
Check the oil pressure is normal, check whether the failure of hydraulic tappet.
Remove the oil pan check lubricating oil pump, filter, replacement of lubricating oil pump; dismantling the valve mechanism, replacing the hydraulic tappet and the valve guide.