water circulation problem

[bbse]

I think I have figured out part of my over heating problem. I got it hot and (carefully) removed the cap. The water is not circulating. Last saturday I changed the t-stat, radiator cap and cleaned the radiator inside and out but the temperature was still fluctuating rapidly. It was doing better so I did some bushhogging and the temp stayed at mid range. The strange thing was when I mowed sideways the temp would shoot up and come back down when I leveled out. This is weird but now I am thinking water pump. I came home today and ran it till it was in the mid range and took the cap off. nothing moving. Any ideas? Can the impeller stop moving water? /forums/images/graemlins/confused.gif

 

[JerryG]

If the thermostat is closed, there will not be any water moving in the radiator.

 

[bbse]

I part of what I did was change the t-stat

 

[JerryG]

I have a feeling that you are not waiting long enough with the rpm up high enough.

 

[bbse]

How high should the temp guage go before the t-stat opens. I checked it at 1/3, 1/2 and 2/3 up. No circulation at any point. I drove it around a while and checked again. I think I wil remove the t-stat and then it should circulate constantly. Shouldn't it?

 

[VictorW]

I have never had this problem with a tractor. I used to work in a Chevrolet dealership. T-stats should operate the same in both. With no t-stat, the water should flow constantly. Most of the time, t-stats don't start to open until closer to their rated temp. You may have to wait until at least 3/4 temp and then it should open slowly until the proper temp is reached. I have seen water pumps go bad on GM vehicles where the impeller comes lose on the shaft but this isn't common. I'd take the t-stat out first and try your test. Then, I'd pull the pump. You didn't say how old the tractor is and was wondering if the radiator is plugged inside. Let us know what you find out. I'm sure the members can get you going.

 

[Powhatan]

Just a silly question, but I guess you put the thermostat in right. You can get it in backwards and cause this problem. The water pump can cause this problem, but like the guy before me stated the impellar coming loose on the shaft is rare, but it does happen.

 

[JerryG]

I don't know what temp. thermostat Kubota uses, but there has been some owners here that have reported that the gage will not even register until the tractor has been worked hard or the radiator has plugged up. How far is your gage moving up? Fast fluctuating is usually a sign that there is still air space in the system and that it is low on water. After filling the radiator, have you topped it off again?

 

[bbse]

It is a 1995 LK3054. Saturday I took the radiator off of the tractor. I washed out the cooling fins until I could see through every slit. I changed the thermostat to one of the exact physical size, though it is not a Kioti brand, and 180f. I ran a heavy duty radiator cleaner in for 4 hours. The inside of the radiator does not look that bad but I am not a radiator expert. I did use water only for all the testing. It runs ok on temp and actually gets hotter at idle, under load or strangely when it is not level. I have a suspicion that it may be a head gasket. it does not surge or blow water out but there is a steady stream of pressure into the overflow. BTW I did also use a new radiator cap. I am going to try to check the circulation for no other reason than to eliminate that possibility. I have not seen water moving yet. I am perplexed but persistent. /forums/images/graemlins/tongue.gif

 

[bbse]

I missed a few answers. Tractor has 500 hours. There is a little blow by(i.e. some of my head gasket suspicions) I put the new thermostat in spring toward the engine. I will do a boil test when I take it out. As to toping it off I have done several tests. I fill the radiator up and fill the over flow to a marked level. When I let the temp go to max it blows a pint or so out of the radiator into the overflow tank. When I check the radiator it is low by the same amount. I have actually used a suction ball to remove it from the tank and put it back into the radiator and it leveled out. If I keep the temp in the middle to 2/3 range the radiator stays full. Another thing, when I ran it Monday until the temp gauge went all the way to 3/4 hot I popped the cap and actually(carefully)felt the water in the radiator. It was not even that hot. i could leave my finger in the water. /forums/images/graemlins/crazy.gif That is when I started suspecting a circulation issue, whether it be a t-stat or a water pump.