It is important that before fitting the replacement unit, the cause of the original turbo failure is identified, and where appropriate, remedial action is taken. Failure to do so may result in similar problems with the replacement turbo, which will not be covered by the turbo warranty.
The six most common causes for failure are:
- Oil starvation
- Oil contamination
- Impact damage
- Blocked engine breathers
- Hot shut down
- Overspeeding (turbo shaft and wheel assembly)
Before installation, always visually check that the replacement turbo is compatible with the unit it is replacing, including oil feed and drain connections and the position of the air and exhaust connections.
Always carefully read any information or instruction labels that may be supplied in the box, or fixed to the turbo or packaging as they may be specific to the turbo supplied.
It is good practice that all ancillary parts should be thoroughly cleaned prior to refitting to the exchange unit.
Priming the turbo
Prime the turbo with the grade of engine oil recommended by the vehicle manufacturer. Do this by filling the oil feed hole with clean oil, whilst slowly rotating the compressor and turbine shaft assembly. Continue until oil runs out of the oil drain hole.
Oil feed and drain
We always recommend that the oil feed pipe and all associated unions and banjo bolts are replaced.
The oil drain pipe and connections should be checked for restrictions and damage and replaced as necessary.
(Do not connect the oil drain pipe until the oil flow has been verified – see STARTING THE ENGINE).
Any gaskets or washers on the oil pipe connections should be replaced.
DO NOT use sealant when fitting the oil feed or drain pipes.
Check that there is a good clean oil supply to the turbocharger and that the flow and pressure are correct.
The engine breathers and associated pipework and valves (including the rocker or cam cover) must be checked to insure that they are clean and operating efficiently.
If the breather system is blocked or restricted, the crankcase can become pressurised. Excessive crankcase pressure can restrict the ability of the oil to drain away from the turbo and so lead to premature turbocharger failure.
Check that the turbocharger connections, air pipes and intercooler are undamaged and completely free of foreign debris, oil and carbon. If in doubt, these items should be professionally cleaned or replaced.
The entire induction system should be checked for damage and leaks, the air filter should also be replaced.
DO NOT use sealant on the induction pipes or connections.
Check that the exhaust gas circulation (EGR) valve is operating correctly.
This must be thoroughly cleaned and checked for cracks, corrosion and distortion. The manifold gasket must be fitted correctly; the securing nuts/ bolts/ studs must be tightened in the correct order and to the correct torque. Bolt and stud threads should be treated with a sealing compound to prevent oil/ coolant leakage.
DO NOT use sealant or sealing paste on the manifold gasket faces or turbo connections.
Oil & oil filters
The engine oil and oil filter must be replaced at the time of turbo installation. DO NOT OVERFILL.
The exhaust system should be checked thoroughly for damage, obstructions and contamination.
Oil or coolant contamination may damage the catalytic convertor / diesel particulate filter and may also cause “smoking” on engine start-up.
Starting the Engine
ALWAYS check oil and coolant levels are correct before starting the engine. Disable the fuel or ignition system and crank the engine via the starter motor until oil flows from the oil drain pipe (to allow the oil pressure to build up within the turbocharger bearings). To prevent starter motor damage, only crank the engine for 10 seconds at a time.
Before starting the engine, reconnect the oil drain pipe.
After starting the engine, allow to idle for at least 2 minutes before increasing the engine speed.
Check that all connections are correctly tightened and that there are no oil or air leaks. Check that the boost pressure is within the manufacturers recommended limits.