Zetor 6211 - Coolant Temperature Gauge

[eoghan_nevin]

Hi, new here, I have a 6211 that I have been trying to get the temperature gauge working. It is a single wire going out to the sensor. I tested it for continuity back to the gauge and it's fine and connections seem fine. The gauge is getting 12V. I ament sure if it's the gauge or sensor ( could it be the thermostat ) . I grounded the sensor wire with key on and gauge moved from full off to full on ( seen that that means the gauge is fine and it's the sensor - others say it doesn't 100% mean that ) Any help would be appreciated!

 

[diyfarmer]

I have a 6211 that I have been trying to get the temperature gauge working. It is a single wire going out to the sensor. I tested it for continuity back to the gauge and it's fine and connections seem fine. The gauge is getting 12V. I ament sure if it's the gauge or sensor ( could it be the thermostat ) . I grounded the sensor wire with key on and gauge moved from full off to full on!

If the clock shows nothing usually that would be the sensor, but you haven't said whether the gauge moves when the engine is warm. If there is no thermostat in the housing it will not show any high reading and will be at the minimum all the time. When it goes to the max with the key on means an earth.

 

[eoghan_nevin]

I have a 6211 that I have been trying to get the temperature gauge working. It is a single wire going out to the sensor. I tested it for continuity back to the gauge and it's fine and connections seem fine. The gauge is getting 12V. I ament sure if it's the gauge or sensor ( could it be the thermostat ) . I grounded the sensor wire with key on and gauge moved from full off to full on!

If the clock shows nothing usually that would be the sensor, but you haven't said whether the gauge moves when the engine is warm. If there is no thermostat in the housing it will not show any high reading and will be at the minimum all the time. When it goes to the max with the key on means an earth.

No it doesn't move at all when engine is warmed up. There is a thermostat bit I'm not sure if that is problem or if it's sensor. The gauge goes up to max with key on when I touch sender wire of an good earth ( which I've seen means they gauge is fine ) is that right ?

 

[eoghan_nevin]

Anybody else have any ideas for me ?

 

[hala]

Take a multimeter and messure the sensor resistans.. The sensor is just a variable resistor and the gauge measure the currant. If the gauge works when conected to earth my belive is a sensor interruption. I do not know the value of the resistance but it is a matter of kohm not mohm.

 

[eoghan_nevin]

Take a multimeter and messure the sensor resistans.. The sensor is just a variable resistor and the gauge measure the currant. If the gauge works when conected to earth my belive is a sensor interruption. I do not know the value of the resistance but it is a matter of kohm not mohm.

I have a voltmeter which doesn't allow me to set the level of resistance I want to measure but will that still work. Also any idea of a rough idea of the resistance I should be looking for and the rough difference expected for a cold and warm engine

 

[ixer0]

Make sure you have the earth wire onto the thermostat housing as it will not earth through the water hoses.
Mike

 

[hala]

The sensor is a NTC type that will say high temp low resistant. I'll measure the value of mine 4340 tomorrow. Try to find out if any currant flows through the sensor by connecting the voltmeter between the sensor and the gauge. Also check so you dont have any bad connection from the gauge and the sensor.

 

[eoghan_nevin]

Make sure you have the earth wire onto the thermostat housing as it will not earth through the water hoses.
Mike

Thanks Mike, you could be onto something there actually. There's only 1 wire on the sensor for the sensor wire that goes to gauge and the sensor is threaded into thermostat housing which is held in place by 3 hoses ( not bolted to any metal piece, so maybe it ain't getting an earth. Doesn't look like a connections has broken off so how does it get it's earth?

Eoghan

 

[eoghan_nevin]

The sensor is a NTC type that will say high temp low resistant. I'll measure the value of mine 4340 tomorrow. Try to find out if any currant flows through the sensor by connecting the voltmeter between the sensor and the gauge. Also check so you dont have any bad connection from the gauge and the sensor.

Thanks that's would be great.

Are you going to you a voltmeters because my fluke voltmeter senses up to 1000 ohms which means it's probably not sensitive enough to tell the difference between cold engine and warm engine resistance values.

How would if test if current flows through it . Set my voltmeter to amps ( current ) and test between sensor and gauge is it ?

Connections are fine as I have tested them. I'm getting 5/6 Volts out at the sensor wire . Is that right ( should it be 12 - seen on some places it should've around 5 going out to sensor )

Thnaks Eoghan

 

[hala]

My temperature sensor 904 ohms at 5 degrees C. Connected to 12V it flows about 15 mA which increases at higher temperature. If you measure the current between the sensor and the meter, a smaller current will flow as the meter has an internal resistance. If there is no current flow, either the sensor or the meter is broken, but if the meter gives full effect when the cable at the sensor is connected to ground directly, it will indicate the sensor.

 

[hala]

Do not know how it is on your model but on 4340 the sensor is located on the thermostat housing and there goes one cable to the sensor and a ground cable to the house itself. Check this ground cable so you have ground to the sensor otherwise no current can flow.

 

[eoghan_nevin]

Do not know how it is on your model but on 4340 the sensor is located on the thermostat housing and there goes one cable to the sensor and a ground cable to the house itself. Check this ground cable so you have ground to the sensor otherwise no current can flow.

Thanks, yeah mine is same , screwed up in to thermostat housing. I have one cable going to gauge but I don't have another connection to po it an earth on it ( maybe it broke ) . Only thing holding it is 3 houses so not connected to any ground I think. I'll check it out and get back to ye.
Thanks

 

[eoghan_nevin]

Ok so tried out a few things. Firstly think the sensor wasn't getting an earth. So put an temporary earth on it.

Took out thermostat housing ( removed 3 houses ). Then took out sensor and checed it - seems fine. Then began to test resistance of sensor . Dipped sensor into tap water ( simulate cold ) and it read 460-500 ohms. Then out it in bear boiling water and read 53 ohms.

Also brought out sensor to tractor and plugged in sender/sensor wire and gave the sensor an earth. Had someone push down key and watch dial. Put sensor into pretty warm water and dial moved up to around 60 degrees !.

So from what I can see it's the sensor and gauge are fine but it's the thermostat that's gone / stuck on open position?

Thanks
Eoghan

 

[eoghan_nevin]

As I think it is Thermostat, is it hard to change out. I know the 4 bolts on housing and separate them and replace gasket when all done but is the thermostat held in or awkward to install ?

Really appreciate all the help

Eoghan

 

[diyfarmer]

As I think it is Thermostat, is it hard to change out. I know the 4 bolts on housing and separate them and replace gasket when all done but is the thermostat held in or awkward to install ?
Eoghan

I was saying to check the thermostat, to take it out of the housing you will have to open the 3 bolts going through housing and might need a screwdriver to get the thermostat up . But take caution opening those 3 bolts as they sit in water and most time they ring off when you try open them.

 

[eoghan_nevin]

I was saying to check the thermostat, to take it out of the housing you will have to open the 3 bolts going through housing and might need a screwdriver to get the thermostat up . But take caution opening those 3 bolts as they sit in water and most time they ring off when you try open them.
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How do I check the thermostat when I have it out though ?
Mine has 4 bolts and a gasket between them. Is the thermostat screwed or held in with clips when the housing is opened. Is there a certain way to put them in ?

 

[diyfarmer]

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How do I check the thermostat when I have it out though ?
Mine has 4 bolts and a gasket between them. Is the thermostat screwed or held in with clips when the housing is opened. Is there a certain way to put them in ?
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Whether yours 4 bolts or 3 I said makes no difference, the same principal applies, the thermostat is in the housing and be careful opening the bolts or they'll ring off. The thermostat is just sitting in but maybe stuck, the sensor end goes down. Maybe able to check it a bucket of boiling water it should pop open. Have look at this picture https://www.benzworld.org/attachments/engine_thermostat_flow_open_closed-jpg.500778/

 

[eoghan_nevin]

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Whether yours 4 bolts or 3 I said makes no difference, the same principal applies, the thermostat is in the housing and be careful opening the bolts or they'll ring off. The thermostat is just sitting in but maybe stuck, the sensor end goes down. Maybe able to check it a bucket of boiling water it should pop open. Have look at this picture https://www.benzworld.org/attachments/engine_thermostat_flow_open_closed-jpg.500778/

Ok thanks I'm currently trying to source a thermostat and gasket and I'll change it .

Is it possible to check the thermostat while it is in thermostat housing.

 

[diyfarmer]

Is it possible to check the thermostat while it is in thermostat housing.

The two ways you know if it's working is 1) the gauge would move to the last if the thermostat was stuck closed. or 2) the heater in the cab blows hot air when the tractor is warm from work.

Did you have it open in the past?