555c backhoe overheating

[hidesertrat]

Background: Tractor would overheat and additional coolant would need to be added. Found the bypass hose was leaking, bleeding off coolant.

Replaced upper, lower and bypass hoses. While I had the hoses off, ran water through block and radiator to flush the system a little. Replaced radiator cap with 13psi cap. Radiator washed, vanes all look good and are free of debris. Once I put hoses one and filled with coolant, pressure tested the cooling system @15 PSI, pressure held well.

Ran tractor for about two hours and the temp needle remained in the "green" zone, Thought all was good. Went out the next day and checked the coolant, had to add about a gallon. :unsure:


Ran tractor for a about four or five hours, temp was good. Stayed in the middle of the green zone. The thermostat had been replaced prior to my introduction the the tractor, engine running in the green seems to indicate the thermostat is opening and operating okay.
However, when I shut off tractor the radiator blew off, sending coolant out the overflow hose. While it was doing this, it sounded as if the water was boiling, but could have just been the water getting past the radiator cap. I allowed the tractor to cool and checked the coolant the next day. Had to add another gallon.
Seems the engine runs at a good temp, but than blows off coolant when shut down. If you don't add coolant prior to starting the engine, it is going to overheat due to low coolant level.

1. What would cause the evacuation of coolant when you shut off engine, when the engine isn't registering as hot? Would a higher PSI cap be a solution? What would the disadvantage be of putting higher PSI cap on?
2. Has anyone installed a overflow tank on a 555c? I purchase a aftermarket one at AutoZone, but there doesn't seem to be a good spot to install it on the tractor.
3. Possible water pump? Best way to check?

Ran the tractor for about an hour this evening. The gauge got a little past the middle of the second green square, normal range. I had secured a gallon jug to the side of the tractor and ran the overflow tube into it. After the hour of running, the bottle was full and air was bubbling out of the overflow tube. Not sure if more than a gallon of water had been lost, the bottle may of overflowed without me noticing it. Letting things cool down before I add water to see how much was lost. The engine was at about 200 degrees, measured at the head, by the exhaust ports.

I believe the water is being pushed out the overflow, not because it is overheating but for some other reason. As the radiator looses water, the engine begins to build heat, which in turn causes more water loss. Just a circle.

I did let the tractor idle for a bit before shutting it off and it didn't blow off water like last time. Maybe because of letting it idle, it wasn't hot enough or there isn't enough water left to blow off.

Would really like to figure out what is causing this. Tractor has 7200 hours on it. At one time, it didn't overheat, so would like to get back to that point.....

Ideas of what and how to check what may be the cause?

Sorry for the long post.

[gecko.cx]

While I had the hoses off, ran water through block and radiator to flush the system a little. Replaced radiator cap with 13psi cap.

Did you just flush it with water or did you use one of the cooling system additives?
Both times I've used the additives, they've loosened a lot of debris which then lodged in the radiator blocking it.

Would a higher PSI cap be a solution? What would the disadvantage be of putting higher PSI cap on?

With a higher rated cap, you run the risk of bursting the radiator.

One possibility is the cooling system is mostly blocked. It allows enough coolant circulation while the pump is spinning, but too restricted to allow enough thermosyphon to prevent boiling once the engine is stopped.

You won't like it, but you need to consider a blown head gasket too.

[essexpete]

Is that the 4 cyl Ford tractor engine? I would be checking Ian Gecko's suggestion. When the machine has stood cool overnight, take out the oil drain plug carefully and see if there is any water collecting at the bottom of the sump. I have had this happen without the oil looking totally emulsified on the dip stick. Also after a few minutes from first start, release the rad cap slowly to see if you have any rapid pressure build. I have similar symptoms with a Ford in an old telehandler.
The other possibility, and even worse than head gasket, is the block going porous due to cavitation eroding the water jacket part of the block. The Ford tractor engines of the 70s and 80s have a bit of a reputation for that.

[hidesertrat]

Thanks for all the ideas. I don't believe it is a head gasket as I don't get bubbles in the radiator while the cap is off and tractor is running. My experience is a head gasket will cause bubbles and enough pressure to blow water out of the radiator. Still...... hoping I am right on this one.

https://youtube.com/shorts/BP9hLpgMEf4

This is a video of the water inside the radiator, while tractor is running at operating temp. I feel there should be more movement to the water as the pump is moving water through the engine. I am leaning towards the water pump being bad and not moving water as is needed. This doesn't rule out a blockage, but it is something I may need to check out.

I didn't put any additives in the flushing process, just plugged off lower port on engine, filled engine with water and released plug to allow water to run out quickly. Did this, until I was getting fairly clean water out. Same thing for the radiator. I know this isn't the greatest method, but it was what was available at the time.

I will pull the oil plug and check for water.

[gecko.cx]

Castrol (and probably others) make test strips to check for combustions products in the coolant. A pack is not cheap, but you may be able to chat-up your local radiator place for a single strip. "Knowing" the head gasket is ok is very confidence building.

I know you said the thermostat has been replaced, but I'd be checking it regardless - for opening travel, temp, and to make sure it's got the correct bleed hole or rattle pin as appropriate (I don't know the engine, so I don't know what it should have).

[essexpete]

Thanks for all the ideas. I don't believe it is a head gasket as I don't get bubbles in the radiator while the cap is off and tractor is running. My experience is a head gasket will cause bubbles and enough pressure to blow water out of the radiator. Still...... hoping I am right on this one.

https://youtube.com/shorts/BP9hLpgMEf4

This is a video of the water inside the radiator, while tractor is running at operating temp. I feel there should be more movement to the water as the pump is moving water through the engine. I am leaning towards the water pump being bad and not moving water as is needed. This doesn't rule out a blockage, but it is something I may need to check out.

I didn't put any additives in the flushing process, just plugged off lower port on engine, filled engine with water and released plug to allow water to run out quickly. Did this, until I was getting fairly clean water out. Same thing for the radiator. I know this isn't the greatest method, but it was what was available at the time.

I will pull the oil plug and check for water.

I found water in my one yet, initially, the oil looked black. I have not sorted the problem as the handler is just a standby and it starts even in cold weather. It must have got worse as now the oil looks slightly emulsified and there is oil sludge in the rad as well. I need to get it sorted but has not been priority.