4 cylinders + 6 cylinders 4 cylinders + 6 cylinders - Steyr Motors

ToC SERVICE MANUAL MARINE ENGINES
05 COOLING SYSTEM
05.00.04 Check points for problems in cooling system
1 Raw water circuit
1.1 water intake - clogged
1.2 raw water filter - clogged
- strongly contaminated
- filter defective
1.3 hoses - fragile or leaky
1.4 hose clamps - loose or defective
1.5 raw water pump - impeller stronlgy worn
- impeller broken
- cover loose
- shaft bearing defective
1.6 tandem cooler - clogged
- leaky
- broken
1.7 intercooler - pipes clogged
- internal leakage
1.8 exhaust manifold - heat exchanger clogged
- internal leakage
1.9 cooling water temperature sensor - defective
1.10 manifold, elbows, seals, hoses - wrongly mounted seals
- sand or dross in manifold
- burned out hoses
1.11 hull - state of hull
- marine vegetation
- equipment attached to hull
NOTE:
Mountings protruding over the hull may produce cavitations during fast ride which cause air
bubbles. These are possibly taken at the lower gear box by the drive and mixed with the
inflowing cooling water. Due to bad refrigerating capacity of the external cooling system, an
overheating in the internal cooling system (engine) may occur.
2 Internal Cooling Circuit
2.1 hoses - craked or leaky
2.2 hose clamps - loose or defective
2.3 thermostat - thermostat defective
- wrong thermostat
2.4 cooler cap - defective excess-pressure valve
- defective vacuum valve
- damaged cover sealing
2.5 coolant circulating pump - defective casing sealing
- damaged bearing
- worn impeller
- defective slide ring sealing
2.6 coolant guide on cylinder block - leaky connectors
Z001019/0_6_July 2008 Page COOLING SYSTEM - 9