jcb G20 Operator's Manual page 134

Intake air or exhaust leaks.
Engine compression low in one or more cylinders.
Electrical sensor fault.
One or more fuel injector worn or malfunctioning.
Inlet and exhaust valve clearances set incorrectly.
Cause
Operating for extended periods under light or no load
conditions.
Intake air or exhaust leaks.
Turbocharger lubricating oil drain line obstructed.
Exhaust leak at the Manifold or Turbocharger
Valve guide seals are leaking.
Electrical sensor fault.
One or more fuel injector worn or malfunctioning.
Lubricating Oil
Cause
Oil leaks.
Oil level over-full.
Incorrect lubricating oil (specification of viscosity).
Crank case ventilation (CCV) system blocked).
Lubricating oil cooler leak.
Turbocharger leaking lubricating oil to the air intake
or exhaust (if fitted).
Valve guide seals are leaking.
Piston rings not sealing - lubricating oil being con-
sumed by the engine (blue smoke from exhaust).
Worn cylinder bores - lubricating oil being consumed
by the engine (blue smoke from exhaust).
Glazed cylinder bores.
Cause
Coolant in the lubricating oil, internal engine compo-
nent leaks.
127
Table 38. Fuel/Oil - Leaking from Exhaust Manifold
Table 39. Lubricating Oil - Consumption Excessive
Table 40. Lubricating Oil - Contaminated
9831/0650-3
WARNING: Fine jets of fluid at high pressure can
penetrate the skin. Keep face and hands well clear of
pressurised fluid and wear protective glasses. If fluid
penetrates your skin, get medical help immediately.
Refer to Table 34. and Refer to Table 35.
Check the engine compression.
Check the electrical connections at the sensors.
Check the electrical connections at the injectors.
Set the valve clearances to the recommended clear-
ances.
Remedy
Review operation for correct gear shifts, deceleration
and idling.
Refer to Table 34. and Refer to Table 35.
Check/clean line.
Check/correct leaks in the manifold or turbocharger
gaskets. Look for a cracked manifold.
Replace valve guide stem seals as required.
Check the electrical connections at the sensors.
Check the electrical connections at the injectors.
Remedy
Inspect the engine for visible signs of leaks. Pay par-
ticular attentions to seals, gaskets oil cooler and ex-
ternal connections.
Check oil level.
Make sure the correct lubricating oil is being used.
Refer to Fluids, Lubricants and Capacities
Check for reduced viscosity from dilution with fuel.
Fuel dilution in lubricating oil can originate from a de-
fective fuel injection pump driveshaft seal.
Review/reduce the lubricating oil change intervals.
Check the breather tube area for signs of lubricating
oil loss. Check and if necessary replace the CCV fil-
ter.
Check for lubricating oil in the coolant.
Inspect the air crossover tube for evidence of lubri-
cating oil transfer.
Replace valve guide stem seals as required.
Check the engine compression.
Check the engine compression.
De-glaze bores as required.
Remedy
Refer to Table 43.
Maintenance
Fault-Finding
127