How to understand if the water pump is working properly.

Some things to check....

it does not have a temperature controller, thermostat. could this be the problem? Without a thermostat, should you see movement in the radiator cap? sorry if I ask too many questions ..

Requires a 9S3808 (170 degree) regulator. Heat transfer is not efficiently done if water flow is to fast through the system. May or may not see motion at fill cap if radiator has a top tank baffle. Everything needs to be correct for proper cooling.
Also check the fan drive belts and pulley wear for slippage.

[quote="Old Magnet"]Requires a 9S3808 (170 degree) regulator. Heat transfer is not efficiently done if water flow is to fast through the system. May or may not see motion at fill cap if radiator has a top tank baffle. Everything needs to be correct for proper cooling.
Also check the fan drive belts and pulley wear for slippage.[/quote]

thank you.
without you I wouldn't know how to do ...
very kind, as always

I've tried a quart of muriatic acid in a 10 gallon system. Unfortunately it didn't stop the overheating. Might have helped soften up the stuff clogging the tubes in the radiator core though. I ended up cleaning the core by removing the top radiator tank and running a rod down each tube. Couldn't get through about 10% of them but the other 90% did the job once they were cleaned.

hello thanks a lot.
Should I disconnect the inlet and outlet pipes?
Do I run the system with the engine running?
how long acidic?

[quote="uisum"]hello thanks a lot.
Should I disconnect the inlet and outlet pipes?
Do I run the system with the engine running?
how long acidic?[/quote]
I drained the coolant, filled with water and added the muriatic acid. I ran the D6 tractor for a day before draining the water and replacing the coolant.

Like I said, it didn't make any big difference in cooling performance. I think you need to have some method of monitoring pH to determine when you need to add more acid. Big problem is the acid won't work on clogged tubes, just those that are partially clogged.