1025R - need auxiilary overheat warning, does anyone have ideas for sensors?

[DirtyHandsCleanSoul]

I need an auxiliary overheat warning on my 1025R. It will be operating in an environment full of dust and chaff and it is going to plug the screens and overheat. This is not a mower tractor, it will be operating a custom built piece of equipment in an industrial setting. I chose the 1025R because it has a real radiator that is easy to blow out. The last machine was air cooled and died after the cooling fins under the heat shields plugged up with crap and the plastic drain plug melted, causing it to do its own oil change. Actually it ran for awhile after that but threw a rod shortly afterwards. Ventrac + Kawasaki.

I would like to build something that cuts out the PTO as soon as the temperature reaches an above normal point. Basically just a normally closed relay wired in series with the PTO switch. The relay will be tripped through either an overheat switch or some microcontroller reading a temperature sensor. If the tractor overheats the relay opens and the PTO cuts out. I believe the x700 machines do this before they completely overheat.

I haven't even started poking around under the hood yet, but does anyone know of a specific place to plumb in a temperature sensor/switch? Is there a nice unused hole somewhere? It would be great if I didn't have to splice into the main coolant/radiator hoses. Does anyone have a specific source for a sensor/switch that they would recommend?

I've noticed that the temperature gauge is not a real gauge, but an idiot gauge like you would find in your car. Ie it has 3 basic positions, low, normal, and overheat. If its operating anywhere withing normal range the needle just points to that one position and never drifts. I want to know when its on the high end of normal and the gauge wont indicate that. Doers anyone know if the factory sensor is at least a real sensor? Or is it just an overheat switch? If its a real sensor then I can just read its value (microcontroller) and go from there. I'd rather have the system completely independent (both for warranty and extra safety) but that would work.

 

[dusty3030]

How about just a power unit. It will have all that built in the control box.

Engines, Inc. :: OEM Products -- Open Power Units

 

[DirtyHandsCleanSoul]

Its a mobile application. It needs to drive around with an operator.

 

[CNC Dan]

What you want is a temperature switch(s).

Check the surplus electronics places.
Or places like digi-key.

You can just tape them to a radiator hose, and add some insulation so the switch isn't cooled by the air.

Get a few of different temperatures, and you can have a warning light come on before your PTO cuts out.

 

[SimS]

You could get an inline radiator hose switch adapter and wire up a temp switch/relay to turn off/on idiot lights and pto, etc. They make adapters for all sizes of hoses and fittings. Here's an example on a popular auction site.
38mm 1 5" Water Temp Sensor Adaptor Gauge Radiator Hose Blue | eBay

SimS

 

[varmint]

I added an oil pressure gauge, a voltmeter and a temperature gauge to my old B8200 for under $20. The sending unit for the temp. gauge installed in a plugged hole in the thermostat housing, using a metric adaptor that came with the gauge kit. It was an easy, and I believe fairly accurate, way to monitor how the engine was running. Look your cooling system over, and see if there isn't a place to screw in a sending unit?

 

[Fallon]

If your diesel engine overheats, you want to keep it running but dump the load (turn off the PTO) on it. That way it will cool itself off rather than shutting down & letting it cook with the cooling system shutdown. Obviously you'd want to kill the engine if it lost oil pressure.

 

[DirtyHandsCleanSoul]

That looks really good varmint. Do you remember the source of the gauge kit? I looked over the engine quick and found a couple screws holding nothing together on the cooling system. I think one of them might be a bleed screw. Ill try pulling those and see what comes out. You did a really clean install of those gauges.

I found some tapped holes around a freeze plug too. It would be super simple to mill up an adapter with two through holes for bolts, an o ring, and a tapped hole for whatever sensor I want.

If your diesel engine overheats, you want to keep it running but dump the load (turn off the PTO) on it. That way it will cool itself off rather than shutting down & letting it cook with the cooling system shutdown. Obviously you'd want to kill the engine if it lost oil pressure.

I'm sorry, was that a question? Yes, that's what I want to do.

 

[CalG]

Search KLIXON , or something near.

All mechanical, will switch real currents, and they come in many temperature ranges and a few mounting configuration. 240F NC should be a good start. ;-)

 

[jaotguy]

find ANY temp sensor with a screw base ... tap any hole in the block near the water jacket ( not necessary to get into the water jacket ) to match the new sensor .... then connect a Normally Closed relay in series with the PTO wire ( breaks the circuit when it opens if overheated ) ... Ign hot wire thru a 10K pot ( pick 1 either side pin and the middle pin ) , to the 12v side of the relay activation pins , other side of the relay activation pin to the lead on the new sensor ...


then start the engine and block off the rad so it starts to overheat a bit ... adjust the pot till the relay kicks out ... remove the cardboard blocking the rad .... as the temp drops, the PTO should kick back in ....

disconnect the wire to the new temp sensor , measure the resistance of the pot and sub in a 1 watt resistor close to the value ... ( or leave the pot in place to give you a variable cut out )


or use a VW mark 1 (2 pin) rad temp sensor ( big screw base ) ... mount to engine ... then ign wire thru the energizing pins of a NC relay ( as above ) , then to either pin of the sensor and the other sensor pin connects to ground ... if the sensor overheats , it will turn the relay off ...