Kubota 1140 CPX Overheating

C

Chip L

New member
Howdy all. Made a smart purchase at auction (didn't read description because I was under the reserve: Ha- they lifted the reserve and I got it - cheap but,...).
Was told it overheats and needed new head gasket. Did a test on the radiator with check fluid. It stayed blue (3 tries). Changed oil, no froth or bubbles there. No steam or smoke from tail pipe.
It runs cold for a while then temp spikes, then drops quickly, then repeats until it overheats. Stays cold at idle, only overheats under load. Funny in that it blows the top off the overflow reservoir and blows steam and water. Seems like I'm getting air in from somewhere and loosing coolant. Replaced thermostat and also ran without one, flushed radiator and engine until water ran clear. Blew out radiator and fan is hard wired to key and runs continuously.

I'm stumped. Maybe the head gasket is blown? It is a diesel.
 
The head gasket is rarely the issue. These kubota engines will crack the head before the head gasket fails. I would replace the head sooner than later. Running it like it is has the effect of bending the connecting rods. If in doubt, have the head magnafluxed.
 
I agree the head may be cracked because that is the common result from overheating but first things first and always confirm the simple things before major tear down. If the test fluid doesn't show hydrocarbons and it definitely is thermo siphoning. I might be wrong but there have been occasions when the impeller has failed on these.
 
I will check the pump. Is there a trick to checking? I see a flow of water but could be the thermo syphoning.

since zero steam from the tailpipe, I am convinced it's something else. A cracked head would still get water in the oil and steam, wouldn't it?).

I plan to take thermostat out and run to eliminate any question there. Again, at idle and low speed, no real issues, mainly under load. That make me think water pump.
 
You can take out the thermostat and rig up a electric drill to run the water pump engine off. You should see flow. You can also just remove the pump and inspect it for damage deterioration and if it's good just proceed to take the head off and have it checked. You can pop test the injectors first to see if it's over fueling? Has the tamper proof been messed with on the injector pump?
 
Yep, that really sounds like a water pump issue to me. I'd check the water pump before I tore into the head gasket. A lot cheaper place to start! Also, make sure you bleed the air out of the system good; a big air pocket near the thermostat housing can cause that same bouncy temp pattern.
 
Okay, frustration x2. New water pump. Water really moving (sans thermostat). At idle, runs cold. Takes a while to warm then goes hot then cold (repeat) under load only. At idle, runs cold. Acts just like a bad thermostat but since I pulled it... Funny I start with a topped off radiator. after cool down, water is low. I do get bubbles in the flow but they slow after running for several minutes.
Zero steam from tail. Starts and runs smooth as glass. no oil in water/no water in oil. It has 2 radiator caps, one at radiator, on between Rad and thermostat (that links to overflow bowl). Do I have the wrong cap on the overflow (it has a spring)
 
Sadly I am starting to think that too. But, why the temp swings? and zero steam or contaminated oil/antifreeze? Seems like at least one would present?
 
New idea: The buggy has a transmission oil cooler. Since the temp spikes then drops, could it be a but in the trans that's causing a bunch of heat? That would tie with it not getting hot while idling, only when moving.

Props to the tech support folks at Messicks for helping me with this thought.
 
It might not work as intended without a thermostat so replace with a thermostat that you have tested in the kitchen. I doubt the oil cooler would cause this issue. Also check to see that your fans are cycling properly and should confirm that your actual overheating
 
aurthuritis said:
It might not work as intended without a thermostat so replace with a thermostat that you have tested in the kitchen. I doubt the oil cooler would cause this issue. Also check to see that your fans are cycling properly and should confirm that your actual overheating
Click to expand...
Done, done and done. Used my infrared tester to confirm not a gauge issue. the overheat only happens when moving. I let it idle for 10-15 minutes and it barely moved the temp needle. when driving (fairly hard) triggers the temp spikes.
 
Have you checked for exhaust restrictions? Has the fuel settings been tampered with? Or the injection timing? You can pop test the injectors also.
 
Well curious update. Did another combustion gas test. Constant streams of bubbles without me even using the bulb. Nice, BLUE bubbles. Never could get the fluid to turn yellow/green which indicates exhaust gases in coolant. continues to get hot then cool. ZERO steam outta tail. I am convinced it is a head gasket but please give me a proper sign. Well, time to get my hands greasy.
 
Chip L said:
Well curious update. Did another combustion gas test. Constant streams of bubbles without me even using the bulb. Nice, BLUE bubbles. Never could get the fluid to turn yellow/green which indicates exhaust gases in coolant. continues to get hot then cool. ZERO steam outta tail. I am convinced it is a head gasket but please give me a proper sign. Well, time to get my hands greasy.
Click to expand...
Check that head closely when you get it off. I'm betting on cracked head.
 
You must log in or register to reply here.
Top