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High water temp only when driving
Good evening, I am having trouble with high coolant temp while driving and running all 3 cruise-air A/C units. I can maintain 170-195F parked for days on end. As I start to drive down the road the coolant temp gradually rises. It has risen to the point of shut down.
I have replaced the water pump (bearing failure),all hoses, belts to pump and fan motor, thoroughly clean out radiator fins, and installed a new thermostat last fall. I was certain I bled all air from the system using bleeders and monitoring return flow to the coolant tank.
Ran the genny non-stop on a 4 day trip to Connecticut in June, temp ran up to 220+while driving but never shutdown. Ran a short trip in late June (1.5hr) and genny shutdown and boiled out water.
I found fan belt in mid-ship radiator fan was loose. Re-tighten belt and blew out radiator fins again, also installed a stiffener flap for belly mounted air baffles, thinking the old rubber was too weak and changing air flow under bus.
Recent weekend trip,the coolant temps are better but still drifting too high when cruising at highway speed. Remedy currently is to shutdown an A/C unit to control coolant temp.
This problem seems to me to be an air flow issue? Also, fresh air fan to genny bay is working and has been cleaned out.
What do you guys think?
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3 Replies
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Sorry, genny is a 20kw Marathon powered with a Kubota turbo… I think its 2.3L.
Radiator is mid ship behind the front axle and draws cooling air from the front axle void. The cruise airs are in front of the front axle and rear unit also draws its cooling air from the void area of the front axle.
The radiator and cruise airs both exhaust their heat out the bottom of the coach.
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Our generators usually draw air from below the bus, so if we are traveling on highways getting heated by the sun, the air the generator needs for cooling can be very hot. When we are parked the ground beneath the bus is shaded by the bus so the generator cooling air is close to ambient temp.
A second consideration is baffling. All three of my coaches had various baffles intended to prevent the air heated by the radiator from returning to the air intake.
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Thank you
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