temp / pressure working range

[andregrondin]

Hello !

I've search the forum ( the right way hopefully)

I've been thru the parts catalog as well as the repair manual and I can't find
what is the tempature range of the running diesel ( is it between 100 to 160 or form 140 to 240 )


found the normal range of oil pressure:

serial -22836 = 30 to 40 psi
serial 22837 -= 45 to 65 psi

so if I undertand properly then my dozer ( serial 08883T) would be under the range of 30 to 40 psi .

no gauges are working and it pi... me off !!

I try to fix all the gauges ( TEMP/ OIL PRESSURE / AMMETER )
so far from what I found would be that the temp sender is short ( been removed and test with voltmeter in DIODE test mode )


so I will try to test the gauge itself but I'm not sure how .
I want to put 12v direct from battery to gauge + & - on each terminal to find out if the needle is moving properly .

any tricks an help welcome

[440 iron popper]

Hi André,

Operating temperature of an old diesel engine is between 160 F to 185 F.

For the temperature gauge problem. There are 2 types I know on old machines. In both cases the sender is a variable resistor.

1. 3 wires gauge with +, Signal, -. You put 12V on + and a potentiometer between signal and - wich is also grounded. If you change the resistor value (turning the pot) the needle will move accordingly.

2. 2 wires gauge with + and -. You put 12V on +. Then a potentiometer on - and the other side of it to the ground. Again when turning the pot, the needle will follow. In this setup, if you put 12V directly to the + et - terminals, the needle will go Overheat!



You can get replacement with Stewart warner I guess. You might also consider changing to a mechanical gauge that is not very expensive.

I hope that helps.

[andregrondin]

Hi !

Ironpopper , thank you for the help ,

here is what I have done

1- remove the sensor from the motor ( scary moment cause it was
jammed ).

2- clean the sensor of paint and rust.

3- tested with voltmeter in DIODE mode ( means that when you touch
the leads together you hear BEEEEP , meaning ther is continuity) so it
means it is not OPEN which is good .




4- connect leads at both end of the sensor , put the volmeter in OHM
mode , reading zero OHM then heat up the sensor gently with a very
small butane torch and start seing OHM going slightly up meaning the
sensor is still good .






so far my diagnostic is that the sensor is good and performing well.

next step will be checking the gauge itself and also checking that ther is no short anywhere,

What I will do to check the gauge will be to connect it has it is suppose to be and heat-up the sensor with the torch .


I will post pics