[southoz]

My '99 model 2388 chewed out another water pump (it was only 2 seasons old) a few days ago and got rather hot but did not boil any coolant. We replaced it and the fan belt (usually shred about 1 per year of those also!) re-filled coolant and expected to get going again. Within about one minute of harvesting the temp gauge was on the edge of the red again, so stopped and tried to cool down the engine but it didn't want to drop, even on idle on a cool day. Now we have tried just about everything we and all the local service guys can think of to stop this occurring but it's still getting hot with virtually no load on the engine and cool weather. We have removed the radiator and had rods through every core, flow tested to check, replaced the thermostats, radiator hoses, cleaned the rest of the air-box components, replaced the oil cooler heat exchange as a small amount of raw oil was found in the radiator, checked the water pump spins freely by hand and that the belt is driving not slipping. After all this and the temp gauge still sits in the red so, using one of those laser temp testing guns we found the following readings in degrees Celsius; radiator top tank - 65, radiator bottom tank - 25, Cast iron thermostat housing both above and below the actual thermostats - 95 approx! It would appear the radiator is fine but the coolant flow is restricted , or could we have an air lock somewhere stopping coolant leaving the block? Don't know where else to look! Forgot to add there are no air bubbles whatsoever in the top tank that might indicate a blown head gasket. Thanks for any help.

 

[doorknob]

Yikes!!!!! Did you measure the amount of coolant you removed and replaced? I allways start there when I do any cooling system work. Engines with thermostats are prone to airlock.

? Did they make 2 rotation direction pumps for those engines? Was it a reman pump, or did you rebuild it yourself?

I have'nt seen those thermostats, but is it possible to install them backwards? (just asking, not trying to question your mechanical abilities)

 

[placeholder]

Maybe it's just a bad sensor? I know my combine this summer was doing some funny things about getting hot once in a while.

 

[mx270a]

When I was on the harvest run in 2004, I had a coolant temp sensor go out on me. The needle never came up off when the engine warmed up. I found out that there are really two sensors. One goes to the gauge, the other will disengage the header if it gets too hot.

-Lance

 

[southoz]

I am relieved to say that we found the problem with the cooling system today.
After checking the calibration of the temp gauge i found that to be accurate ie; when the gauge shows the normal operating temp (needle in middle of first green section) the thermostat area is approx 65 degrees C, when the needle got to the start of the red section the thermostat area showed 106 degrees C.
So the next thing i tried was removing the brand new, genuine Case IH part, water pump (a new high vollume version) to see if anything could be wrong with that. I was relieved when i saw that the impellor which is simply pressed onto the shaft, had come loose and was allowing the shaft to spin freely. In fact it was quite a loose fit onto the shaft and it fell off onto the floor when the pump was removed.
So this poorly made pump cost us a lot of expense and downtime, I recommend to anyone fitting a new pump that they check how well the impellor is pressed onto the shaft!
We got another pump in from Cummins and now the combine is running perfectly. Thanks to the guys who replied with their suggestions.