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Curtis B.
Curtis B., Technician
Category: Construction and Road Equipment
Satisfied Customers: 1207
Experience:  Technican turned service manager with multiple lines of equipment and rental units.
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I have a 1997 312B caterpillar excavator. We are having problems

Customer Question

I have a 1997 312B caterpillar excavator. We are having problems with the cooling system. we have changed the rad, water pump, thermostat, rad cap and flush the cooling system with cat's rad flush and changed the air fillers. The hoe has 17000 hrs. on it. What happens is when we start unit and start running the unit on high speed. depending on the outside temp. the temp will hit the top end with in 20 to 30 mins. We taken off the rad cap we can see the fluid circulating freely. There are no bubbles or oil in the coolant. We do not loss coolant. The engine oil is free of coolant. I was wandering if it is possible 1 of the heads could have a crack some were and how we could find out witch head is the problem.
Submitted: 2 years ago.
Category: Construction and Road Equipment
Expert:  catmastertech replied 2 years ago.
Hello,If your head was cracked, you would build combustion gases in the cooling system and this would cause a coolant loss. Is the air flow through the radiator and oil coolers clear all around the assembly? Are the foam baffles still on the hood and sealing the sides or the radiator?(It is important the air flow is sealed from the engine compartment so that only outside air will enter.)Has the pump loading become excessive? (lugging the engine too much)Does this machine have the high ambient air temperature package? If so, have you replaced the pulleys and v-belts with the correct type parts for high ambient cooling?What is the temperature drop from the outlet to the inlet of the radiator?Please include the full machine serial number with your reply.