Model M John Deere, lower radiator hose cold?

john_bud · Apr 18, 2014

I'd back flush it and see if that changes anything.

RickB · Apr 19, 2014

psychonautbuddy said:
Alright, did a couple laps with brush hog, then I got out my digital multi meter, plugged in the thermometer, and got 212f sampling thru the radiator cap. I'm about a 50/50 mix.

I felt the lower hose, and the cast iron flange into the block, and it was barely above room temp. I popped off the sheet metal, felt accross the face of the radiator, hot at top,
warm in the middle, and so-so at the bottom of the fins. Putting my fingers on the lower tank, about room temp.

My guess is my radiator is clogged up! Funny though, it looked okay from the inside the cap.

If I get some positive feedback, I'll yank it and unsolder the bottom tank, rod it with an old dip-stick, and see what happens.

Whatcha say? Should this be in the part/repair forum?

If you run it for a longer period of time with similar results, I'd say the radiator was working well. Hot in, cool out, I'd say that is all good. Now if you get hot out and a high gauge reading or test temp, that's different.

psychonautbuddy · Apr 23, 2014

I added 1 gallon water, cleaned leaf/grass debris off the radiator, flushed one quart out at the low point plug, and worked it for about 45 minutes, then took a temp. reading. Running about 10f cooler, at 202f.
I think it's going to be okay. Thanks everyone.

stuckmotor · Apr 23, 2014

Did you get a temp reading from the water jacket around the block and head? Was it hot?

CalG · Apr 23, 2014

RickB said:
We're discussing an underdesigned thermosyphon system here. One that typically is complained about due to overly high operating temps. If you had any direct knowledge of or experience with this particular system, just about the last bit of advise you would give is to cover all or part of the radiator.

If I may add.

The Fordson E27n is a "enhanced" thermosiphon system. That is, the system has wide open passages, with the addition of a belt driven impeller to move the fluid flow along. Original equipment had a "calorimeter" on the tank head, and a canvas blind for blocking the heat exchanger (radiator, though radiation has little to do with the cooling effect)

I picked up a couple of very nice large dial face 90 degrees thermometers to replace the missing original many years back.
When blowing snow in winter, (can you blow snow in the summer? ;-) with the "radiator" blind wide open, the coolant temperature never got to 140 F. The engine ran OK, but...

With the blind up and modulated to hold the coolant temperature right at the boiling point, There is a noticable increase on engine power, AND a discernable "throaty" quality to the exhaust note. The fuel jet in the carb can be opened another 1/8th turn as well.

I'm sold on running as hot as the coolant will allow without boiling losses. (even boiling is OK as long as it doesn't get out of hand and run the level low.)

Just a real life experience report on the topic.

cheers

pmsmechanic · Apr 23, 2014

Thank you CalG. You statement was a lot more elegant than mine would have been.

psychonautbuddy · Apr 24, 2014

stuckmotor said:
Did you get a temp reading from the water jacket around the block and head? Was it hot?

No! I should have done that. I took it at same place, just inside the cap. Maybe I need to find a plug or something on the jacket. Sounds messy & scalding....

It's not boiling, so it can't be overheating, because if it were, I would have killed it by now. I'm not cutting grass, it's a brush-war!

CalG · Apr 24, 2014

May I add

I haven't a clue regarding the bottom coolant temperature.

The E27n is all cast iron, top tank and bottom collector. I trust the "calor-metre" as it's business end is submerged in coolant about 10 cm ;-)

I do know that the cooling fan pulls a nice flow of warm air over me whilst moving slowly on a cold day ;-) At times I would like a canvas surround as well!

stuckmotor · Apr 24, 2014

What I had in mind was checking the temp at several places on the outside of the water jacket, not pulling any plugs. It should be easy with a non contact thermometer. Harbor Freight sells them cheap.
I think there's a flow test that technicians do on radiators where they dump a certain amount of water into the top and time how long it takes to come out the bottom. A web search might give specifics.
It's been 40 years since we had an M and I my memory is not the best but, I don't ever remember the water boiling. It had a heavy radiator cap and I'm not sure whether this was some early type of pressurization cap, whether it was Deere issue, aftermarket, or whether the radiator was even pressurized.
Good luck.

psychonautbuddy said:
No! I should have done that. I took it at same place, just inside the cap. Maybe I need to find a plug or something on the jacket. Sounds messy & scalding....

It's not boiling, so it can't be overheating, because if it were, I would have killed it by now. I'm not cutting grass, it's a brush-war!

psychonautbuddy · Apr 25, 2014

The coolant never "boiled". It just seemed weird when I noticed the lower hose was much cooler to the touch, maybe only 10-20f above ambient.
I've never considered "pouring water into the top and see how fast it comes out the bottom" as a test. I like it. The cap is wore out. I keep it on
there to stop squirrels from nesting there.