Kubota L3650 overheats

[rbargeron]

Hey Airdriver - any news on the overheating situation? If it's not too late I'd like to change my recommendation to take off and inspect the water pump. It may come to that but it would be easier to check the radiator first.

Maybe you could try disconnecting the hoses from the radiator and running a garden hose into the top connection to see if full flow comes out the bottom. The flow should come barreling out the bottom right away - if it ponds up in the top tank or seems slow starting to come out, or runs a long time after taking the hose out, then not enough tubes are passing flow. If questionable, take the radiator to a shop for rodding out or new core.

A friend has a Nissan Maxima that has been running gradually hotter for a year - he looked at everything except the radiator - but that's what it needed. Take care, Dick B

 

[Airdriver]

When it started leaking through the shaft, I changed the water pump. Inspection of the old pump revealed nothing out of the ordinary. Impeller was metal and firmly attached to the shaft.

The temp gauge now goes up way more than normal, but does not get into the red zone. Perhaps it is the indicator gauge itself.....there are still no other indications than the gauge.

Hal

 

[ritschner]

Get yourself a infrared thermometer, they are fairly inexpensive, easy to use, and handy for several different uses. You can then take a reading on the intake side of the cylinder head and get within a couple of degrees of the actual coolant temperature. The red zone on the gauge is usually between 220 and 240 degrees on a diesel. I would second a vote on the gauge itself.

 

[oldcarkook]

Your symptoms are typical of a radiator that is plugged or scaled. The temp is not peaking to boilover (yet), but likely running hot since you've verified that senders and units are all operating properly. The water pump failure is additional indication of free minerals in the cooling system as they have abraded the water pump shaft and opened a seal leak.

I would pull the radiator and have it flow tested by a competent radiator shop. All radiators have a flow rate and over time, PARTICULARLY in a radiator that was not running inhibited antifreeze or had "tap water" added (overheat?) or tap water diluted antifreeze put into the cooling system. What are you running for coolant in the system now? Distilled water used to make up any dilutions?

Tap water has minerals in it that will precipitate when in an enclosed cooling system. Tractors that have been in service and had a plugged radiator screen (seed?) and overheated and lost coolant in the field, may often be topped off with water that is available which could be anything from pond water to tap water. It's all a guessing game, but for sure there is chemistry, dissimilar metals, and ions that all play a role in whether or not the calcium, magnesium, manganese, and iron that are in the source water will precipitate out on the inside of the radiator, but the white scale INSIDE the radiator is a very strong indication that you have plaque - like a plugged artery. It's in the engine block too but normally this is a far more forgiving area just on mass alone.

The radiator is a heat exchange unit and when you add a layer of mineral to the inside, you inhibit the heat exchange efficiency. That would explain why the temp is high but not boiling over. It's on the edge.

Running engines hot is never a good thing to do and getting your motor back into proper operating range is critical to lifespan.

I think you need think about dealing with the radiator and determine if it needs a recore or replacement depending on price and what's available.