I’ve got a komatsu excavator (pc45 mr-3) that has recently began to overheat when tracking or under a load after about 30 to 45 minutes. I’ve checked the coolant and flushed first. Hydraulic and engine oil levels are proper. Started out first changing out thermostat and temp sensor. Still overheating Changed out water pump next. Still over heating. Cleaned the radiator and did a little better but still overheating. Just installed a brand new radiator and ran for about an hour and still overheating. I haven’t let it get to redline level but it is over heating after working for about 30-45 minutes still. I can idle down - open up the access doors and it will cool down to proper temps in a matter of less than 5 minutes. Any ideas or suggestions?
Just a couple things you might want to check: Does the turbo have a waste gate? If so, is it functioning? I have also seen the inside baffles of a muffler break and get dislodged causing high back pressure. The muffler I seen was on a 988 loader. Nearly burned the loader down from all the heat under the hood.
What engine is in this excavator?
4d88e - yanmar
Ok I thought it might be a Cummins. I would check the fan speed make sure it is turning as fast as engine, I've had some engines where the fan belt would slip and not turn fan fast enough. You may want to drain your coolant and pull the temp sensor out and then refill coolant to make sure you don't get an air pocket in the engine.
You really need to verify the temps with an outside source, like an IR gun, before you throw any more expensive parts at this.
Update - installed all brand new thermostat, temp sensor, water pump, and radiator. shot the machine with infrared temp gun and didn’t find anything out of line. got a combustion leak detector - nothing showing the head gasket was leaking Ended up unscrewing the new temp sensor about 3 turns and shooting the machine with the IR thermometer… temps are reading good and all is well after really digging/working the machine. Sometimes it’s the simple things that will get ya!! I was relying on the gauge on the machine and it was really my error
Thats interesting I have a CAT 312 & overheating after 1/2-3/4 hour on 2-3 clicks. The muffler fell off on its brackets & the baffles are missing with one stuck inside. I reattached it but will buy a new muffler now. It has a turbo? Not saying thats my problem but best get a new one.