Overheat on first cold day

Gadgetnut · Dec 7, 2009

We had a cold snap for us, 28 degrees. This morning my helper had been using the ToolCat for light duty use (no hydraulic tool, just driving around the property) for 45 minutes. With no warning, he hadn't noticed the temperature gauge rising, a warning light came on the dash and he saw smoke and turned off ToolCat. Lots of smoke, looks like most of the antifreeze boiled out. I followed a trail of leaking antifreeze a few hundred feet. We're going to let it cool. We'll look for a missing belt, a hose failure, the radiator cap, see if the fan comes on... what else should we look for? Overheating under light duty on such a cold day? Thanks. -Gadgetnut

Gadgetnut · Dec 7, 2009

Followup. After it cooled we started machine no problem. Raised the bed and examined the engine. Belts seem to be fine, the coolant reservoir cap was tight and made a light vacuum sound as we released it. The coolant reservoir is completely empty. No sign of broken hose. The fan blade is unobstructed-- spins freely at rest. We put some coolant in it and drove it up to the shop and parked it-- seemed to run fine.

Any input as to why we would experience a sudden overheat like this?

Next step, I was going to start engine and let it run warm up to temperature and see if any coolant leaks are visible under pressure and if the fan ever cycles on.

radman1 · Dec 7, 2009

Thermostat stuck shut? Is the cooling fan running when engine hot? I think you need to run it again under some load and watch the temp gauge and see if it repeats. Wild guess but may be cooling fan.

DEWFPO · Dec 7, 2009

Can you tell where the coolant was leaking from? Engine block heater, freeze plug, etc...

DEWFPO

Gadgetnut · Dec 7, 2009

Hi Rad. Given I haven't yet found any disruptions or leaks in the coolant lines, the cooling fan not coming on seemed like a possible cause.

Hi DEWFPO. When it became known the coolant was boiling out we turned off the machine and couldn't raise the dump said to see what was happening. The coolant was dripping down directly underneath the coolant reservoir. I don't know where coolant is intended to discharge from in a boilover situation. After things had cooled off we refilled the coolant reservoir with maybe a half gallon of Bobcat antifreeze and it held-- no apparent leaks sitting or operating for 5 minutes.

Like I said, my next step might be to let the machine come up to operating temperature again and see if the cooling fan ever triggers on. Other?

Spudgunner · Dec 7, 2009

I believe the cooling fan is hyd-powered. You might check the fluid level. I'd try to exactly re-create the failure mode.

BTW, it's supposed get down to +2 here tomorrow AM.

Gadgetnut · Dec 7, 2009

Spud, you mean check the fluid level to make sure the cooling fan has hydraulic flow? Yes the cooling fan is definitely hydraulic, I was thinking there is an electric thermostat somewhere that sends a message, start the fan. Over the next few days I'll try to re-create what happened today, which was quite strange. BTW, Spud, I lived in Idaho for twelve years, so I know. Pretty funny but I was thinking of you when I started this thread earlier... my first words were, "We had a cold snap for us, 28 degrees..."

Spudgunner · Dec 7, 2009

Yes, just the hyd fluid level. Might as well knock-off the easy stuff first. From looking at the service manual (for the "D"), it appears that the fan controller can throw codes (35-xx). You might check that as well. Looking at the wiring schematics it appears that the temp. sensor is an input into one of the controllers and there's a controller output that controls the fan solenoid. Not much help...sorry.

theoshin · Dec 9, 2009

Gadgetnut said:
Spud, you mean check the fluid level to make sure the cooling fan has hydraulic flow? Yes the cooling fan is definitely hydraulic, I was thinking there is an electric thermostat somewhere that sends a message, start the fan. Over the next few days I'll try to re-create what happened today, which was quite strange. BTW, Spud, I lived in Idaho for twelve years, so I know. Pretty funny but I was thinking of you when I started this thread earlier... my first words were, "We had a cold snap for us, 28 degrees..."

the key point is if your fan is turning on or not. if not that really narrows the potential culprits. if it is running and the radiator is clear then things may be more complicated.

ts