B-2400 Overheat issue

[Wisco608]

I have a B-2400 that has an overheating issue. Do not know age other than 350 hrs. Has cab with Aux heating unit and FEL.

At mid rpm range it will leak out the overflow not a steady flow. The temp gauge will be about 1/2 way up. Usuall

At Near WOT it will overheat after about 15 min of run time and the gauge will show about 3/4 the way up and it will spew fluid but never run dry of coolant.

There is no white smoke or black blue smoke from the exhaust, other than the initial blue/black smoke on initial start up which is nothing more than a puff of smoke.

To Date:
Cleaned radiator fins from outside.
Cleaned radiator screen
Flushed Radiator and Block

Yesterday ran it at high rpm on level garage floor without radiator cap on. I observed good flow across the radiator through the filler neck. I reduced the RPM’s to idle and observed the level rise with a small amount run out the overflow. I did observe some bubbles escape the filler neck at the rate of 1 small bubble every 5-7 seconds.

I attempted to pressure test the system however the loaner cap/rad pressure test kit from the auto parts store does not fit the B-2400 rad filler neck cap.

How do I pressure test the system?

I’m also reluctant to doing the pressure test, if it is a simple head gasket and the coolant flows into the combustion chamber I don’t want to hydro lock or bend a rod. I suppose I can pull glow plugs and crank it to determine if it’s going in the block which should eliminate hydro, the pull dipstick if it flows into the oil.

I’m not on the ledge yet, if anyone has any other ideas or recommendations I’m all ears.

 

[JerryMT]

I have a B-2400 that has an overheating issue. Do not know age other than 350 hrs. Has cab with Aux heating unit and FEL.

At mid rpm range it will leak out the overflow not a steady flow. The temp gauge will be about 1/2 way up. Usuall

At Near WOT it will overheat after about 15 min of run time and the gauge will show about 3/4 the way up and it will spew fluid but never run dry of coolant.

There is no white smoke or black blue smoke from the exhaust, other than the initial blue/black smoke on initial start up which is nothing more than a puff of smoke.

To Date:
Cleaned radiator fins from outside.
Cleaned radiator screen
Flushed Radiator and Block

Yesterday ran it at high rpm on level garage floor without radiator cap on. I observed good flow across the radiator through the filler neck. I reduced the RPM’s to idle and observed the level rise with a small amount run out the overflow. I did observe some bubbles escape the filler neck at the rate of 1 small bubble every 5-7 seconds.

I attempted to pressure test the system however the loaner cap/rad pressure test kit from the auto parts store does not fit the B-2400 rad filler neck cap.

How do I pressure test the system?

I’m also reluctant to doing the pressure test, if it is a simple head gasket and the coolant flows into the combustion chamber I don’t want to hydro lock or bend a rod. I suppose I can pull glow plugs and crank it to determine if it’s going in the block which should eliminate hydro, the pull dipstick if it flows into the oil.

I’m not on the ledge yet, if anyone has any other ideas or recommendations I’m all ears.

Coolant coming out of the overflow does not mean an engine is overheating. It could mean you overfilled the cooling system and as the coolant temperature increases and it flows out the overflow. Since you flushed the cooling system, a few trapped bubbles might be coming out.
Put your radiator cap on get the engine up to temperature by working it , get an infrared thermometer (~$20) and measure the temperature on the outlet end of the thermostat housing. Depending on your pressure cap rating you should see temperatures less than ~235°F.

This next step requires some caution. Shut the engine down, wait about 15 minutes and then CAREFULLY, using a rag, slightly open the radiator cap to relieve the pressure. DO NOT OPEN IT FULLY BUT MERELY OPEN IT UNTIL YOU HEAR IT HISS. When it stops hissing open it a bit more. If it hisses, let it stop. Do this until you get the cap off. Then with the cap off, re-start the engine and look for bubbles in the coolant by looking in the radiator neck. If you see a continuous stream of bubbles than you can suspect a leaking head gasket or a cracked head.

 

[Wisco608]

>JerryMT I will check as you described. Thank you for taking the time to write this up for me. I will report my findings.

 

[Roadworthy]

When you cleaned the radiator fins I hope you blew them out or rinsed them out from back to front. You want to force any dirt or seeds back out the way they came. You do seem to have an over temperature issue based on your description. Have you checked your thermostat? If it sticks closed it will cause overheating. A pressure cap doesn't protect you from overheating. Its purpose is to allow the coolant to run hotter without boiling.

 

[Pau7220]

When you cleaned the radiator fins I hope you blew them out or rinsed them out from back to front. You want to force any dirt or seeds back out the way they came

I don't know the airflow of a B2400 but this advice would be incorrect on my L3650. Airflow through radiator goes from engine side to the front of the tractor... so you would blow and hose out from the front.

 

[Wisco608]

>JerryMT I will check as you described. Thank you for taking the time to write this up for me. I will report my findings.

Update:
Last evening I followed the steps you recommended. The Temperature at the thermostat housing was 198F That was after running at high RPM’s running the loader to mix up a dirt pile and driving it short distances, to get it up to temp.

I did observe a small dribble of coolant running from the overflow of the radiator, however with the engine running I was able to squeeze the upper radiator hose and there was zero pressure on the hose.

I moved to step 2 and did not observe a steady stream of bubbles.

The findings would suggest that the radiator cap should be replaced.
Thoughts?

 

[Pau7220]

The findings would suggest that the radiator cap should be replaced.
Thoughts?

Absolutely....... It's one of the most overlooked parts of any cooling system.

 

[Blue280z]

If rad cap is not issue then it is probably the head gasket going.

From cold, run at idle with rad cap off and look for bubbles

 

[Russell King]

Inspect the radiator neck where the cap seals, sometimes that is messed up and won’t seal even with a new cap.

 

[Wisco608]

Thank you for the

When you cleaned the radiator fins I hope you blew them out or rinsed them out from back to front. You want to force any dirt or seeds back out the way they came. You do seem to have an over temperature issue based on your description. Have you checked your thermostat? If it sticks closed it will cause overheating. A pressure cap doesn't protect you from overheating. Its purpose is to allow the coolant to run hotter without boiling.

If rad cap is not issue then it is probably the head gasket going.

From cold, run at idle with rad cap off and look for bubbles

wheew I do not have bubbles like that

 

[Blue280z]

If you adjust the rpm's to the right freq at idle, you can minimize tractor vibration at certain rpms and get the water surface in the rad to be glass smooth. This helps see tiny bubbles.

There should be no bubbles when warmed up. Even small ones. A sloshing water surface makes it hard to see tiny bubbles.

When a HG starts to fail, you will only see tiny bubbles at first.

 

[Blkvoodoo]

That tractor does not have a coolant recovery tank, so as the engine heats up the fluid expands and has to go somewhere, so it goes out the rad cap and the drain tube. Being there is no recovery tank to draw back in from, you loose what’s pushed out. Once it has reached about 1/3 level of upper tank, you won’t loose any more unless it gets hotter than it had previously.
I was concerned with this on my own B2400 until I realized there was no recovery tank.
You could make one easy enough, a simple 16-20oz soda bottle would work and drop the drain hose in that, I haven’t done it as it hasn’t been a priority. Mines been fine in the 1490hrs I’ve run it.

 

[Wisco608]

If you adjust the rpm's to the right freq at idle, you can minimize tractor vibration at certain rpms and get the water surface in the rad to be glass smooth. This helps see tiny bubbles.

There should be no bubbles when warmed up. Even small ones. A sloshing water surface makes it hard to see tiny bubbles.

When a HG starts to fail, you will only see tiny bubbles at first.

Ok so today is May 4, 2022 and thought I had the overheat issue fixed. Ran all winter plowing snow with no issues. Now it’s spring well kinda here in Wisconsin but warm enough to be the grass growing. I picked up a 60 inch mid mowed the lawn takes about 1 hour and at the end of the run it started getting warm and was spewing coolant out the overflow. So the rad cap wasn’t the issue. So replaced the thermostat and just got in from mowing and sure enough same deal. Gonna pull the radiator and check flow looks like some scale inside also going to check to water pump while I’m at it…… will check for bubble yet again.
Will the head gasket failing Into the combustion chamber show signs of “steam cleaning” on the glow plug kinda like a spark plug on a gas engine? I’m not blowing any white smoke.

 

[Dieseldonato]

Get a pressure test adapter to fit your radiator and pressure test the system. Right now your just aimlessly replacing parts. A temp of 198*f is perfectly safe and very close to most thermostat opening temps. A 190* thermostat will open between 185*- 200*f. If you keep filling the radiator to the top of the tank it will keep over flowing. The fluid level needs to be kept about an inch or so below the fill neck to allow for expansion. Also since you apparently got an ir temp gun, you can scan over a hot radiator to find any blockages. They will show up as a localized cold spot. Cooler fluid should be toward the bottom of the radiator. Hot in the top cool out the bottom. Some basic testing will rule out the head gasket and any possible leaks/ blockages. Water pumps typically let you know when they go bad. Haven't ever seen a kubota impeller let loose, typically it's the bearings that go bad but they don't really seem to be a major issue from my experience.

 

[Blue280z]

I fixed my G5200 overheating with a few grenades thrown at it at once so I do not know for sure which one did the trick. Your 2400 is larger and hopefully does not have a small rad like the 5200 so comparing may not be reasonable.

One low-cost grenade you could try is to drain the coolant and run with Evaporust for a couple of weeks then flush it out.