Apparent overheating issues and cooling system flush

Hi all! I'm working on a 1850-hour 1979 MF230 with the Perkins diesel and and catching up on a lot of deferred maintenance.

When taking it for a test drive, I noticed that after <90 seconds, the temp gauge is at the top end of the 'green' (though it gets there gradually from the lower end of the gauge.

The rad is clean, and the fan is sucking a lot of air

Here's what I've done:

1. I drained the existing coolant. It was black, full of rust, with some slight oilyness to it. I flushed through the radiator and block until the water was coming out clear.

2. Filled the tractor with water, ran it for a few minutes. Temp gauge acts same as before, drained the water, it was black again, flushed through until clear. rad clears up with a few litres through. Block takes about 10-20 gallons before it runs clear.

3. Repeated #2 twice more (after letting it cool down). Gauge still goes to the hot end quickly, the water still drains black.

I *think* the thermostat is operating properly as the needle doesn't ever go fully into the red, but the temp hovers at the high end of 'normal'.

I assume the water pump is working and water flows through the rad, because the water in the bottom rad hose is warm.

So my questions are:

1. Should I continue to run and flush the tractor until the water comes clear after flushing? This could take a long, long time... I suppose I could bring it up near the house, stick a garden hose with a moderate flow on it, and run the tractor. It looks like just rust water now, so I don't need to worry about the grass...

2. Any thoughts about what could be keeping the temp gauge so high? I don't think it's just a dirty cooling system as despite several flushes it hasn't improved.

Try this test:
Next time you have a cool engine (completely cool), start it up and let run until the lower hose starts to feel warm. Then, pay attention to the upper hose and see if it starts to get warm. If not, then your water pump not working.

Have you had this tractor long? Any gauges or parts been replaced lately?

90 seconds isn't enough time for a cold engine to overheat. I would double check the temperature gauge and sender, especially if it is electric.

(quoted from post at 08:16:34 06/06/17) Try this test:
Next time you have a cool engine (completely cool), start it up and let run until the lower hose starts to feel warm. Then, pay attention to the upper hose and see if it starts to get warm. If not, then your water pump not working.

Have you had this tractor long? Any gauges or parts been replaced lately?

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Hmm, unfortunately the top rad hose would require me to stick my fingers through the fan! However, I can confirm that the coolant at the top gets warm, though I haven't stuck my fingers in to see if it's *hot*.

Had the tractor for about a week. Haven't replaced anything other than the main fluids and filters.

Can you borrow an infrared heat meter to check temperatures from a safe distance? Cheap ones start around $15.

I would install a known to be accurate guage(even if only temporarly) marked in degrees. Using radiator flush will make cleaning much faster.

Absolutely agree with the 90 seconds isn't long enough to overheat!

Black oily coolant is an indication of a leaking head gasket or cracked head on a diesel.

Need to run a combustion leak test to verify if that has happened.

Once the problem is fixed, try some laundry detergent in the cooling system, let it run an hour or so, flush it out with the thermostatout or a heater hose open, some way to get the block to flush, then replace the antifreeze.
Combustion Leak Tester

stop at your local grocery store and pick up a candy thermometer. basically a dial on a long metal rod. slide put the thermometer in the radiator and start the tractor and watch your temperatures. that will tell you if the gauge is bad. as far as a coolant flush, i use straight white vinegar. drain the system and fill with straight vinegar. run it a while then let it sit over night. run again the next day and get it warmed up. then drain the system. let it cool a little then flush with fresh water severeal times. you can add baking soda to help neutralize the vinegar. works good and its not an overly agressive acid.

The only way the temperature can climb that fast is if you have a combustion leak and the sender gets surrounded by exhaust gasses.

Caterpillar recommends Cascade powder dishwasher soap, just mixed up the soap in water and pour into the radiator, just pouring the powder in causes the powder to cake up and stop the flow, so mix up well. I also have hooked a hose from the hot water faucet to the block drain and back flushed an engine.

From what I have read, you are still getting crap out of the system. First guess on the temp. gauge is that the sender is totally gunked up and needs replacing. The Vinegat flush is a good idea. HTH

Sounds like a bad head gasket. Fill the radiator up to the very top then run at idle or a little faster. If you see bubbles
then you need to pull the head and have it checked.

Water pump impeller could be
Completely rusted off

So, to follow up on this:

I bought an infrared thermometer and bought a bottle of Prestone Rad Flush (this one: https://www.amazon.ca/Prestone-AS105-Radiator-Flush-Cleaner/dp/B00B99U088)

I then ran the machine for a while to get the block temperature up to 180 as read from the outside (took about 30 minutes at 2000RPM) with the coolant cap off. Used the thermostat to watch the rad fluid and lower hose temps. I never got it to climb past 180 really, but the operating temp seemed linear to the RPM, and I didn't want to push it too much higher.

The fluid in the rad neck got to ~140 degrees or so. The lower hose got to ~110 degrees. They pretty much stayed there

Once I shut the tractor down, the fluid in the upper rad neck went up to ~155 degrees.

My main thought is that the rad temps never got to where they should be if the thermostat and water pump were both operating. Given the amount of rust and gunk in the system, I think it's realistic that one or both is either clogged or junk.

180 on block temp is not really completely warmed up; you really sure there is a problem.

(quoted from post at 06:01:09 06/07/17) 180 on block temp is not really completely warmed up; you really sure there is a problem.

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What should I read for it to be completely warmed up? Maybe I'll drag around a bush hog for a while to see if I can get it higher today.

Brian

I do not know what thermostat is in it, so 5-10 degrees above that, the block will be a little cooler because the water flows up and out the head, so measure head temperature. I would think 182 on block and 192 on head would be perfectly acceptable temperatures with a 185 or 188 thermostat. You would raise or lower those numbers based on thermostat and loading. It is not abnormal for head temperature to run above 200-205 degrees with a 195 thermostat in place. The pressure cap on the radiator takes care of raising the boiling point.

If the temperature keeps going up, then you have a problem.

Get a combustion gas test strip for the antifreeze before taking anything apart.

(quoted from post at 06:30:40 06/07/17) I do not know what thermostat is in it, so 5-10 degrees above that, the block will be a little cooler because the water flows up and out the head, so measure head temperature. I would think 182 on block and 192 on head would be perfectly acceptable temperatures with a 185 or 188 thermostat. You would raise or lower those numbers based on thermostat and loading. It is not abnormal for head temperature to run above 200-205 degrees with a 195 thermostat in place. The pressure cap on the radiator takes care of raising the boiling point.

If the temperature keeps going up, then you have a problem.

Get a combustion gas test strip for the antifreeze before taking anything apart.

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According to the shop manual, the thermostat should start opening at 178 and be fully open at 200.

Did some bushhogging to get her nice and warm. Block temp got up to ~195. Radiator top got to 185 degrees, and the bottom host got to ~160.

However, the bottom hose got signifigantly warmer as you followed it towards the engine, which makes me wonder if it was just heating up from the engine's heat rather than carrying water that has passed through the rad...