Overheating

[North Idaho Wolfman]

Head was surfaced when he block was re-sleeved.

HUGE RED FLAG!
Did you add a shim to make up for the milling on the head.
And Milling the head does not mean it was inspected for cracks.

How long does it take to heat up?
If it's real quick it's not the radiators problem.

 

[Blitzz]

Exactly. Until you confirm with some kind of known good thermometer (IR gun or otherwise), you don't know you have a problem.




I noticed this earlier and was going to comment, but got sidetracked.

If the coolant doesn't spend enough time in the radiator, it won't shed enough heat and won't get cool enough. It's called, "dwell time".

Don't assume there is something wrong when you aren't even running it according to design.

On another forum, we've seen poeple (usually a kid) one after another spend hundreds of dollars on high flow water pumps, uber-custom radiators, lower temp thermostats, and still have an overheating problem.

Then they put it back to stock and the problem is solved.

Get the t-stat back in place, get an accurate measurement, then you'll know if you have a problem or not.

If you do, my money is on your gunked up block.


Cooling systems are systems, not just a collection of different components. They are designed to work together.

The oem thermostat in in it, the gunk in the block was much less than I thought. Really was only between the welch plugs and the bores. When doing a system flush the water/vinegar comes out the same colour as it went in. I believe it is the cheap radiator if I buy a new one I will let yall know.

 

[Blitzz]

HUGE RED FLAG!
Did you add a shim to make up for the milling on the head.
And Milling the head does not mean it was inspected for cracks.

How long does it take to heat up?
If it's real quick it's not the radiators problem.

Yes we added the head gasket shim, I spared the details but I will go through them all for clarity.
Head magnafluxed, shaved, valve seats done.
It takes 25-30 min to get to 230, depending on the load. Mainly when I am cutting grass, the mower doesn't seem to bog it really at all but its enough to get it too hot. I can drive around all I want and be fine.

 

[North Idaho Wolfman]

Yes we added the head gasket shim, I spared the details but I will go through them all for clarity.
Head magnafluxed, shaved, valve seats done.
It takes 25-30 min to get to 230, depending on the load. Mainly when I am cutting grass, the mower doesn't seem to bog it really at all but its enough to get it too hot. I can drive around all I want and be fine.

Thanks for the info, it does matter.
New or old water pump?
You might be right, might be just not enough volume flow (air or water) through the radiator.

 

[Blitzz]

Thanks for the info, it does matter.
New or old water pump?
You might be right, might be just not enough volume flow (air or water) through the radiator.

Its a new water pump, old one started to leak. Its an el cheapo radiator from all state ag parts, was only ~$290 compared to $1000 for one from kubota. By the looks of it its made in turkey by kada radiators, you can basically look straight through the radiator, unlike most other radiators where you just get a bit of light.

 

[North Idaho Wolfman]

Its a new water pump, old one started to leak. Its an el cheapo radiator from all state ag parts, was only ~$290 compared to $1000 for one from kubota. By the looks of it its made in turkey by kada radiators, you can basically look straight through the radiator, unlike most other radiators where you just get a bit of light.

Do you still have the old radiator?

 

[Blitzz]

Do you still have the old radiator?

No, when we got the tractor it had been put down because the rear axle seals were leaking, sat for so long that every body panel and sheet metal component wrought off of it.

 

[Russell King]

Since you keep asking about the radiator and cores a little information about the design of a heat exchanger may help. The upper tank and lower tank are also called water boxes. In the older simpler days they had no baffles and the water flowed through one large heat exchanger from hot (top) to cool (bottom). There were no turns involved.

Then cost started to be a concern and the heat exchanger became smaller and more complex. The inlet for the hot water may be way over to one side, the water is blocked by a baffle in the upper tank and forced to the lower tank through only a few tubes and then moves towards the center of the radiator and back up to the upper tank. This would be called a turn (maybe two turns). This could repeat several times across the radiator or be a front and rear arrangement of baffles and tubes.

If you happen to measure the upper tank and lower tank on the same pass of water they may be close to the same temperature.

Did you measure the tank temperature or the upper inlet neck temperature and the lower outlet neck temperature?

Also the infrared sensor can be fooled by some surfaces (shiny?) so take temperature on the radiator hoses to see if that gives any different results.

Another source of limiting the airflow over the radiator is a clogged screen in front of the radiator or some clogged heat exchanger that is in front of the radiator. On my tractor the battery is in front of the radiator blocking off some flow. Just be sure that you have a clear path into the radiator fins since you know the radiator is clean on the outside. It might be clogged upon the water side but that is lower probability since you see good flow of the water.

Edit: now I saw your pictures so ignore the comments on clogged screen

 

[North Idaho Wolfman]

No, when we got the tractor it had been put down because the rear axle seals were leaking, sat for so long that every body panel and sheet metal component wrought off of it.

View attachment 75069

Can you find another radiator about the same size or bigger and use it as a temp test unit?

 

[Blitzz]

Since you keep asking about the radiator and cores a little information about the design of a heat exchanger may help. The upper tank and lower tank are also called water boxes. In the older simpler days they had no baffles and the water flowed through one large heat exchanger from hot (top) to cool (bottom). There were no turns involved.

Then cost started to be a concern and the heat exchanger became smaller and more complex. The inlet for the hot water may be way over to one side, the water is blocked by a baffle in the upper tank and forced to the lower tank through only a few tubes and then moves towards the center of the radiator and back up to the upper tank. This would be called a turn (maybe two turns). This could repeat several times across the radiator or be a front and rear arrangement of baffles and tubes.

If you happen to measure the upper tank and lower tank on the same pass of water they may be close to the same temperature.

Did you measure the tank temperature or the upper inlet neck temperature and the lower outlet neck temperature.

Also the infrared sensor can be fooled bu some surfaces (shiny?) so take temperature on the radiator hoses to see if that gives any different results.

Another source of limiting the airflow over the radiator is a clogged screen in front of the radiator or some clogged heat exchanger that is in front of the radiator. On my tractor the battery is in front of the radiator blocking off some flow. Just be sure that you have a clear path into the radiator fins since you know the radiator is clean on the outside. It might be clogged upon the water side but that is lower probability since you see good flow of the water.

I measured the temp with the IR thermometer initially at the upper neck and the lower neck, then just by measuring at the tanks. There was no difference there, when I measured at the hoses the temp went up a considerable amount, almost 80 degrees, so I didn't go off of the hose measurements which were ~295 F. There is no screen on the radiator, the battery is 6-8" away so I don't think that is a problem.

 

[Blitzz]

Can you find another radiator about the same size or bigger and use it as a temp test unit?

I can take the radiator out of my st30 if that will work, thats down for a cracked frame. If not I have radiators from a couple cars, maybe way too big but its worth a shot.

 

[GeoHorn]

1- I believe you mean pressurizing the cooling system increases the boiling point

2- Coolant flow is not the issue most people think it is. More important is the ability of transfer of heat from the block engine to the coolant and from the coolant to the radiator. Also air flow through the radiator is key. One issue with removing the thermostat is that many diesel engines use the thermostat to block the coolant bypass when the thermostat is open. I know some Kubota engines have this feature and some do not.

THANK YOU for clarifying my intended message. (morning coffee was late) Yes…. agree!

 

[007kubotaguy]

Is it possible that the junk that was in your block has got into the new radiator core and plugged up some of the tubes? I have used many radiators from Allstate tractor parts without any issues.

 

[Blitzz]

Is it possible that the junk that was in your block has got into the new radiator core and plugged up some of the tubes? I have used many radiators from Allstate tractor parts without any issues.

There is a good chance that they are clogged, but I sorta dismissed that because of the amount of flow that I can see. Plus I have flushed the system multiple times.
I will se if I can get it rodded later this week, or even a better core.

 

[dirtydeed]

Ok, one last question. What are you using for coolant?

If antifreeze, is it straight uncut or premixed with water?

 

[GreensvilleJay]

when it's running, scan the block for 'hot' spots. maybe a section of the water jacket is blocked ?

also.. since there's 50+ posts here, perhaps post a 'recap' of what's been done,replaced, observatins,etc. in one post

 

[Blitzz]

Ok, one last question. What are you using for coolant?

If antifreeze, is it straight uncut or premixed with water?

I'm using regular coolant, doesn't ever get below 65 here, I've found that even if I mix 50/50 it doesn't make a difference, we usually run it straight.

 

[Blitzz]

when it's running, scan the block for 'hot' spots. maybe a section of the water jacket is blocked ?

also.. since there's 50+ posts here, perhaps post a 'recap' of what's been done,replaced, observatins,etc. in one post

RECAP: Freshly rebuilt engine D1301-a in a kubota l295dt. New radiator, water pump, thermostat, valves, valve seats, gaskets, bearings, welch plugs, head gasket + shim, radiator cap (14 psi).

Block was re sleeved, head magna fluxed and shaved as it was warped.

There is basically no temp difference between the upper and lower radiator necks,
UPPER NECK TEMP: 200
LOWER NECK TEMP: 198

When I get a chance I will check for hot spots, if none are found I will change he radiator to a temp test unit.

Thanks for the help all, I will keep you updated on my findings. Definitely more complicated than I was expecting.

 

[dirtydeed]

I'm using regular coolant, doesn't ever get below 65 here, I've found that even if I mix 50/50 it doesn't make a difference, we usually run it straight.

Blitzz, let me clarify what I was getting at. Undiluted antifreeze doesn't cool very well at all. Straight antifreeze inhibits heat transfer. That's why I was asking. If you're using a 50/50, then its a moot point.

 

[Blitzz]

The radiator was the problem, got it re-cored by a local shop. They said it wasn't blocked but the core did seem cheap. Runs between 180 and 200 when mowing.