About us

After-sales service

Fault diagnosis guidance, spare parts and field support for turbochargers and blowers.

Updated October 2026

FuYuan after-sales service: turbocharger fault diagnosis guide, spare parts and technical documents.

Troubleshooting common turbocharger faults

Remove the compressor inlet pipe and check the compressor wheel for damage. Turn the wheel with a finger to check that it rotates freely, and feel whether the axial and radial clearances of the turbocharger shaft are normal (reference values: radial clearance < 1 mm; axial clearance ≤ 0.2 mm). In general, unless a wheel has been damaged by a foreign object, the turbocharger is not faulty if it is externally intact, the rotor turns freely, neither wheel rubs against its housing, and the axial and radial clearances feel normal (the wheel does not rub when pressed lightly by hand and rotated).

Fault 1: wheel or rotor shaft damaged by a foreign object

Step	Cause	Inspection method	Responsibility	Remedy when a problem is found
1	A foreign object was drawn into the turbocharger during operation	Remove the compressor inlet pipe and check the wheel and rotor shaft for damage and for marks left by a foreign object. If foreign-object damage is confirmed, check whether the intake piping is poorly sealed or whether an object left inside the piping was drawn in while the turbocharger was running.	User	Replace the turbocharger, correct the faults in the intake and exhaust piping, and make sure the intake piping is airtight. Note: when servicing or repairing the engine, protect the compressor inlet, and before refitting the intake piping check thoroughly that nothing has been left inside it.

Fault 2: abnormal wear of the bearings or rotor shaft

Step	Cause	Inspection method	Responsibility	Remedy
1	When the turbocharger is noisy or makes a rubbing sound, or wear of the bearings or rotor shaft is suspected: remove the compressor inlet pipe and the exhaust pipe at the turbine outlet, check the wheels for damage and look for rubbing marks between wheel and housing. Scoring means the turbocharger is already damaged. Turn the wheel with a finger to check that it rotates freely, and feel whether the axial and radial clearances of the turbocharger shaft are normal (reference values: radial clearance < 1 mm; axial clearance ≤ 0.2 mm). In general, unless a wheel has been damaged by a foreign object, the turbocharger is unlikely to have failed if it is externally intact, the rotor turns freely, neither wheel rubs against its housing, and the axial and radial clearances feel normal (the wheel does not rub when pressed lightly by hand and rotated).			Continue with the checks in the following steps.
2	Hard particles in the oil circuit or poor-quality lubricating oil	Check that the lubricating oil and the oil lines are clean and free of hard particles; check the oil grade and quality to establish whether poor-quality oil has been used (tip: look for sludge, impurities, blackening or gumming in the bearing housing, at the oil inlet and return ports, inside the pipes and in the oil).	User	Clean the lubrication lines, replace the oil filter, change to good-quality lubricating oil and replace the turbocharger.
3	Lack of engine oil	Check the turbocharger oil feed line for kinks, blockage or leaks. Check the oil level with the dipstick. Low oil pressure, or pressure loss in the oil circuit after an engine bearing failure, prevents normal oil supply to the turbocharger.	User	Replace the turbocharger and remove the kink, blockage or leak. Replace the turbocharger and top up the oil. Replace the turbocharger and repair the low oil pressure or engine bearing failure.
4	Loss of dynamic balance caused by dust build-up on the wheel	Visually inspect the wheel surface, the inner wall of the compressor housing inlet and the inner wall of the compressor inlet pipe for adhering dust and sludge. Deposits show that the intake air is too dirty: dust build-up throws the wheel out of balance, and the bearings then fail.	User	Clean the intake piping, correct the failed air filter, the poor filter sealing or the leaking pipe joints, and replace the turbocharger.
5	Improper operation	Ask the user whether any of the following has occurred: Driving by accelerating and then coasting in neutral. Idling for too long (more than 20 minutes). Revving the engine to high speed right after starting, without first running at low speed for 3–5 minutes; or shutting down after a long run without idling for 3–5 minutes first. Ask the driver whether the engine is operated correctly: opening the throttle immediately after starting without idling for at least 3–5 minutes; stopping without idling for at least 3–5 minutes; repeated hot shutdowns; or accelerating and then coasting in neutral. Such practices starve the turbocharger of oil for an instant, and the resulting internal damage leads to housing rub, oil leakage and similar faults. Check whether the oil in the bearing housing is coked or caked.	User	Clean the lubrication lines, change to good-quality lubricating oil and replace the turbocharger; also train the user in correct operation.

Fault 3: oil leakage from the turbocharger

Main signs of turbocharger oil leakage on a vehicle:

1. Heavy smoke from the engine exhaust pipe, usually black or blue;

2. Engine oil seeping from the turbocharger or from the intake and exhaust pipe connections;

3. Reduced engine power and increased fuel consumption.

Step	Cause	Inspection method	Responsibility	Remedy
1	Establish whether the turbocharger itself is damaged	Remove the compressor inlet pipe and check the wheel for damage. Turn the wheel with a finger to check that it rotates freely, and feel whether the axial and radial clearances of the turbocharger shaft are normal (reference values: radial clearance < 1 mm; axial clearance ≤ 0.2 mm). In general, unless a wheel has been damaged by a foreign object, the turbocharger is unlikely to have failed if it is externally intact, the rotor turns freely, neither wheel rubs against its housing, and the axial and radial clearances feel normal (the wheel does not rub when pressed lightly by hand and rotated).		If the wheel or shaft is damaged, the wheel rubs the housing, the shaft clearance is excessive or the rotor does not turn freely, the turbocharger is damaged: replace it and continue with the following steps. If the manual check shows no fault in the turbocharger itself, do not replace it; continue with the following steps.
2	High intake depression (restricted air intake)	Oil or heavy oil traces inside the compressor mean the turbocharger is leaking oil and call for a careful check. With the turbocharger itself intact: Dust has passed the air filter or the filter has failed (look at the dust on the inner wall of the intake pipe and at the cylinder head intake port). Suggestion: clean off the oil, remove the compressor inlet pipe so that the turbocharger draws air directly from the atmosphere, run the engine at medium speed (5–10 min) and high speed (over 20 min) under various conditions, and see whether oil still leaks or the leak is reduced. If the leak stops or is clearly reduced after this, the intake depression is too high: go back and check the intake system. New engines with low mileage: oil or grease applied to the hoses during assembly can leave traces that look like an oil leak.	User User or engine manufacturer	Remove the causes of high intake depression: air filter clogged or failed; intake hose too soft and sucked flat; intake piping with sharp bends or right-angle transitions that restrict the air flow and raise resistance.
3	Loose or cracked intake or exhaust piping		User	Repair the air or gas leak in the piping.
4	Restricted oil return	Check the turbocharger oil return pipe for restricted flow (for example a self-made gasket whose oil hole is misaligned, a pipe blocked with sludge, or a return pipe that is bent, runs too flat or is kinked).	Depends on the case	Restore free oil return.
5	Excessive crankcase pressure	How to check: First check that the crankcase breather and vent pipe are clear, and that the vent pipe is not kinked or obstructed. If they are clear, run the engine at high speed with the oil filler cap open or the breather removed (depending on the engine model) and watch for a clear change in smoke colour; after 20 minutes check whether the oil leak has improved. If it has, investigate the crankcase pressure further.	Depends on the case	Check whether the breather (or breather pipe) is blocked, or consider blow-by caused by worn piston rings or cylinder liners.
6	Hard particles in the oil circuit or poor-quality lubricating oil	Check that the lubricating oil and the oil lines are clean and free of hard particles; check the oil grade and quality to establish whether poor-quality oil has been used (look for sludge or impurities in the bearing housing and in the oil).	User	Clean the lubrication lines, change to good-quality lubricating oil and replace the turbocharger.
	Lack of oil	Oil leaking from the turbocharger oil feed pipe; check: Whether the oil feed line is blocked; low oil pressure, or pressure loss in the oil circuit after an engine bearing failure, prevents normal oil supply to the turbocharger. Whether the oil level is sufficient. Whether the driver operates the engine correctly: opening the throttle immediately after starting without idling for at least 3–5 minutes; stopping without idling for at least 3–5 minutes; repeated hot shutdowns; or accelerating and then coasting in neutral. Such practices starve the turbocharger of oil for an instant, and the resulting internal damage leads to housing rub, oil leakage and similar faults.	User	Repair the oil circuit and replace the damaged turbocharger. Restore the oil level and replace the damaged turbocharger. Have the driver follow correct operating practice and replace the damaged turbocharger.
	Loss of dynamic balance caused by dust build-up on the wheel	Visually inspect the wheel surface, the inner wall of the compressor housing inlet and the inner wall of the compressor inlet pipe for adhering dust and sludge. Deposits show that the intake air is too dirty: dust build-up throws the wheel out of balance, and the bearings then fail.	User	Clean the intake piping, correct the failed air filter, the poor filter sealing or the leaking pipe joints, and replace the turbocharger.
	Improper operation	Confirm with the user whether any of the following has occurred: Driving by accelerating and then coasting in neutral. Idling for too long (more than 20 minutes). Revving the engine to high speed right after starting, without first running at low speed for 3–5 minutes; or shutting down after a long run without idling for 3–5 minutes first. Check whether the oil in the bearing housing is coked or caked.	User	Clean the lubrication lines, change to good-quality lubricating oil and replace the turbocharger; also train the user in correct operation.
7	Quality defect of the turbocharger itself	If the turbocharger still leaks oil after the checks above have ruled out all these causes, a quality defect of the turbocharger itself is very likely.	Supplier	Replace the turbocharger.

After-sales service

Downloads

Technical documents will be published here. Contact us for datasheets.