2355N overheating

K Effective

Well-known Member
1989 2355N, replaced temp sender, thermostat, hoses and radiator this past winter after it showed hot last summer. Laser temp gauge read everything was maintaining 180ish, so assumed the sender was failed. Other parts were replaced because they were original and showed plugging or out of convenience. Now it really is running hot, last night the bottom hose read 181F but block was 220, coolant boiled out of overflow. Hydraulic cooler was very cool by comparison, 160, so I don't suspect a rapid hydraulic recirculation. I did not replace the plastic radiator top tank or cap, could it be not pressurizing? Or do I tear into the water pump?
 
Boiled out or is compression forcing it out ? You can put a radiator pressure tester on it and crank the engine over without starting it and see if the gauge builds pressure ?
 

Is the water pump actually moving the coolant ?
How worn is the fan belt , water pump/fan pulley and the alternator pulley ? Is the belt ,
Pump pulley and alternator pulley new ?
 
Some of these tractors / engines used a plastic water pump impeller. Has the water pump been removed and impeller inspected?? May be broke and or
slipping on hub?? New replacement will be cast iron. DW
 
I usually drill just a very small hole in the thermostat flange to let any trapped air out so coolant can get to the thermostat to open it. Any chance you have air trapped behind the thermostat?
 
More details: Last year, the gauge suddenly started to read off-scale high temp shortly after starting- like less than five minutes, with no work being performed. I used an infrared temp gun to read all surfaces- thermostat housing, hoses, block, all registered ~180F. So I figured the sender had failed, all else seemed to be working.

To get to the sender, one must remove a quite a bit of other stuff, which lead to the thermostat replacement, new water pump belt, all new hoses. I looked inside the radiator after using the coolant system flush from JD, and saw remaining white deposits on the internal tops of the tubes. No true radiator shops near me anymore, none will boil it out like the old days, at least, which is fine. So i ordered a replacement radiator. The tank on top is plastic, and actually communicates pressure with the system vial a hole in the bottom and a tube protruding from the top of the radiator, not just an overflow hose. The cap for this tank os a pressure cap, which I saw no reason to replace. There was a small crack in a corner of the tank, but not all the way through, and it did not leak when first filled and pressurized.

I replaced the thermostat the way the original came out. With 20-30 hours on it, I think any air would have been swept out now, the tank is far above the thermostat housing and the hose does not create a loop seal of any kind.

I don't think it's cylinder pressure, it does not overflow right away, but will get top-of-scale hot after working for a while, then fluid comes out of the overflow.

I have a water pump repair kit already, but after reading the instructions and not having a special tool required, I left the pump as it was. Yes, probably should have taken it off, but it was at that point when I got distracted by the turbo/valve guide seals, and worried about making more unnecessary work, as I already had.

Since the turbo had to come off to get to the thermostat, I looked into it and saw oil. I took it to a shop, but they diagnosed the seals as fine, almost no wear on the bearings, but that the oil was likely from a leaking valve guide seal getting oil in the exhaust side, none on the charge side.

I bought valve guide seals and removed the valve cover, but my older engine does not come with the seals, it was a retrofit or stock on later serial numbers. I had a mechanic look at it and he felt the valve guides were within tolerance to leave well enough alone, rather than pulling the head off.

I had to do a lot of cleaning on the fan when it was off- there was this gritty, black layer of stuff on the fan and shroud, almost like a spray undercoating. I don't know if the variable fan unit uses a fluid that leaked out, but when it was overheating, I didn't think the fan was moving much air, even with the front side shields off.

My first thought was a water pump failure. Then I considered a hydraulic heat overload, like if there was a high-flow open loop causing the hydraulic fluid to overheat, sending the heat the coolant-cooled oil cooler, overloading the radiator. The PTO is hydraulic on this tractor, but I don't think it is a constant flow thing. AND, the temps on the oil cooler were low, lower than the engine temps.

I'm headed to the parts store to eat the cap, and maybe bring the tester home to test the radiator (if it fits the threads)
 
Just got back from three different parts stores, none able to confidently test the cap. Will probably get a new one, cheapest and easiest first step.
 
Since everything is new. The only obstruction I see is the thermostat. If it isn't too hard try removing it, and see how it heats. Next option is a water pump problem. Just last year I had a heating problem on my 401 B. I installed a new radiator, after the shop said it was bad. A thermostat also. My main problem was a bad mechanical gage, at least I have a new radiator. It's been a day since your post I hope you have something figured out by now. Stan
 
Might be easier to heat the old thermostat in a pan of water and see what temp it opens, if it does. Stan
 
If water pump is bad, engine block will be very hot, but lower radiator hose will be cold, at least much colder than top hose.
 
If water pump is bad, engine block will be very hot, but lower radiator hose will be cold, at least much colder than top hose.

This is currently my condition, block read 220-240F, lower hose read 160F.

I bought the water pump rebuild kit around 2000, when very cold out it would drip coolant until it warmed up, never a puddle, but a few drops. I read the instructions and realized my leak+rare winter use=not a priority fix. When I had all this other stuff torn apart, I revisited the pump, but again deferred it. Looks like the second deferral was a poor choice (maybe). When I removed the cap yesterday to get it tested, the coolant level cold is right on the full cold mark of the plastic tank, so what amount boiled out was strictly due to an overfilled condition or extreme expansion- it was never blowing steam out, just drips along the edge of the hood, etc.

I can make it through spraying season with my other narrow 5500N, so I think this one will get parked until winter service time, useful only for moving wagons, etc.

My new radiator cap is due in Tuesday, I'll probably give that a try first before parking it completely. There is a weird, tapered rubber fitting on the inside center of the cap that mates to a plastic stem inside the tank. The rubber edge has been cut/pinched when tightened and is no longer 100%. When I had a tester threaded into the cap, it lifted immediately upon pumping the tester- the numbers on the cap say 1.2 and 0.6, but being German these may be in BAR, or metric, but probably not psig.

This tractor needs to be split again- the rear hydraulic lift pump is failing- when hot it will not supply enough to use the HI/LO and steering will loose flow. That doesn't tie in well with the water pump, but may justify a long-term disability claim...
 
I rally do not suspect the water pump, as it was working before you changed the other components. My bet is still on a thermostat issue, would change that and see if same issues. It was really good you shot the temperatures before and after with IR, that gives you a good benchmark.
 
I think that when I have time, ill pull the hose off the outlet of the pump as i drain the system, and turn it over to see what flow might look like.

Probably go after the thermostat IF we get some rain tonight
 

We had a 1995 GMC Jimmy That was an excellent t vehicle until about 7 years old .
Ran hot one day and then the temp gauge dropped . In fact it later ran cold on the highway .
Pulled the stat and found it sprung and stuck 1/2 open .
A couple of new stats , with a vent hole were installed . No different . Run screaming hot then have the stat stick open .
New hoses , new water pump no different . Had the engine out for rebuild and boiled the block and heads in the tank . Looked into every little coolant passage everywhere .
Never did find the cause . Still ticked off and annoyed that I did not solve the problem .
 

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