MBE4000 APPLICATION AND INSTALLATION
□
Increased engine loading, change in duty cycle
□
Running at more adverse conditions than original system design permits, higher
altitude or temperature
7.15.2
COLD RUNNING ENGINE (OVERCOOLING)
Extended low coolant temperature operation can adversely affect engine performance, fuel
economy, and engine life. Overcooling most frequently occurs at extreme low ambient
temperatures during long idling or low speed and light load operation.
Consider the following for cold running engines:
□
Inaccurate gauge, out of calibration, lack of markings to determine actual temperature,
sensor probe in poor location or not fully submerged in a high coolant
fl
ow area.
□
Closed thermostat core coolant
fl
ow -- Top tank baf
fl
e not completely sealed, standpipe too
short or missing, improper sizing of dearation line or standpipe(s) so
fl
ow to the top tank
exceeds
fi
ll line capacity, over
fi
lled cooling system, reverse core
fl
ow, thermostat coolant
leakage. See test procedures for determining these de
fi
ciencies.
□
Defective thermostat -- Stuck open, worn, misaligned, excessive leakage, improper
calibration, incorrect start to open setting.
□
Insuf
fi
cient engine heat rejection -- Excessive low speed and load or idle operation, idle
setting too low, over concentration of antifreeze and/or inhibitors, cab and fuel heaters,
charge air fan removing heat faster than engine can supply.
□
Fixed fans -- Moves air through core when not required.
□
Shutters/Controls -- Not fully closed, opening temperature too low.
7.15.3
POOR CAB HEATER PERFORMANCE
Poor cab heater performance results from cold running engines.
Inadequate heat in the operator's environment is symptomatic of poor cab heater performance.
Consider the following to solve poor cab heater performance:
□
Engine coolant temperature below normal.
□
Coolant-side causes
□
Air-side causes
□
Thermostat leakage test
□
Radiator top tank baf
fl
e leakage test
□
Top tank imbalance test
1. Check coolant-side cause, low
fl
ow, by investigating the following:
□
Supply and return lines not connected to proper locations on the engine
All information subject to change without notice.
(Rev. 03/06)
7-55
7SA250 0603
Copyright © 2006 DETROIT DIESEL CORPORATION