JD 620 manifold

DavidT1 · Oct 7, 2014

Hello All,
I have a 1957 JD 620 that the heat exchanger I am unable to read if it is on the cold or hot mode. Any easy ways to tell if it is on one or the other without removing the manifold? It is so rusted in with the manifold I cant just remove it either. The tractor has been running in the 200 degree range so I am starting to scratch off the reasons for it running what I can tell is hot. Thanks!!!!

BushogPapa · Oct 7, 2014

I doubt that anyone alive has ever set the Heat to "HOT" on those manifolds..!!!

I would rather suspect sediment in the engine Block, stopped-up radiator or bad water Pump..

If you watch the coolant flow when the tractor is "up to temp" and can see that it IS flowing and the upper water tube (from the engine) gets HOT, the Lower tube TO the engine should be much cooler..
The Water Pump does have a "By-Pass tube" and should circulate coolant in the engine, even if the thermostat is Closed, so the Lower water pipe may be fairly warm.
If the Engine Block has not been FLUSHED in many years, I would drain the coolant and remove the Lower water pipe and un-bolt the attaching nipple from the engine Head and Power-Wash in there until the exiting water runs clear.
Sediment can really build up at the bottom of the cylinders in the engine Block and will restrict coolant flow and cylinder cooling.
Re-assemble and run White Vinegar (50% Water?) in the cooling system, to clean it out, Flush that out and re-fill with Winter Coolant.
Replace Thermostat with a New one.

fixerupper · Oct 7, 2014

Your engine won't run hot with the heat exchanger set on hot unless you are running it under a load on a hot day. I used to set my 630 heat exchanger to hot in the winter so it would warm up faster. Forgot to change it to cold one summer and it didn't get hot till I used it to cultivate corn on a hot day. Jim

gtx1967jewison · Oct 7, 2014

200 is fine when it's doing work

Mike M · Oct 8, 2014

I don't know ? Never tried it but couldn't you just feel for warmth as soon as it starts ? Check the front side and the back side see if the front intake side gets any heat at all.

RLA · Oct 8, 2014

200° is just right, that's where it's suppose to run.. If the engine slowly gets warmer & warmer I would suspect a partially open thermostat. A 620
plowing or discing will run 210 to 225° on a warm
day. Mine will run 190° to 200° raking hay on a cool day. I use a 7.3 Ford Diesel thermostat in
mine & it's 190°..

DavidT1 · Oct 8, 2014

Thanks to you all!! Yes it ran at 200-220 while plowing and disking on a hot day. I DO think I need to clean it out as noted beings this was my Grandfathers tractor and it sat for many years before I got it. Again I appreciate the information as it sounds like everything is right just needs to be flushed.

buickanddeere · Oct 8, 2014

Take the grill off . The rad fins could have 54+ years of oily mud plugging airflow.
Use 50% HD coolant and 50% distilled water.

BushogPapa · Oct 8, 2014

Especially if it has power steering and oil leaks have let oil get on the radiator fin area .

Always Pre-Mix your antifreeze & water before pouring it in, to be sure it circulates.
Very important in any early JD with NO Water Pump..

Ron.

JD 620 manifold

DavidT1

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BushogPapa

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fixerupper

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gtx1967jewison

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Mike M

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RLA

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DavidT1

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buickanddeere

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BushogPapa

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