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CAT E120B Excavator Water Temp Alarm Sounding

parttimefarmer

Active Member
Joined
Apr 19, 2015
Messages
34
Location
minnesota
On the E120B excavator yesterday the water temp gauge lite up and buzzer sounded.
Never did that before.
I hit the lamp reset button and it stops.
Then in a little while a few minutes it comes back on.
Does not do it offen at higher engine RPMs. But at half RPMs it happens offen.
The heater in the cab is blowing hot air.
Anti Freeze is in the radiator.
Fan belts are turning.
Could the water temp gauge be bad?
What else could be the problem?
What ever comments you provide would be greatly appreciated.
Stumped by this.
 

check

Senior Member
Joined
Apr 1, 2012
Messages
800
Location
in the mail
My E70B used to do that. The problem was a dirty connection at the temperature sender on the engine.
Does not do it offen at higher engine RPMs. But at half RPMs it happens offen.
That tells me the higher voltage at higher RPM overcomes a bad connection.

GLTU.
 

parttimefarmer

Active Member
Joined
Apr 19, 2015
Messages
34
Location
minnesota
Hello Nige Wes hoping you would notice my question.
Do you have any ideas as to what could be causing the water temp light and alarm to go off?
 

Nige

Senior Member
Joined
Jun 22, 2011
Messages
28,984
Location
G..G..G..Granville.........!! Fetch your cloth.
Check answered your question in post #2 above. First place to look is at the electrical connection between the machine wiring harness and the coolant temperature sender located on the engine.
Without a machine Serial Number it's impossible to give more details, although the thermostat housing would probably be a good place to start looking.
 

parttimefarmer

Active Member
Joined
Apr 19, 2015
Messages
34
Location
minnesota
Ok some more information.
Stared the excavator today.
After just turning on the key (not starting the engine) the temp gauge moved from high to low, back and forth many times and buzzer when off, the engine did not even start yet.
I turned off key and opened the engine cover and looked around and notice what appear to be smoke or mist a little rising from the cab side of the engine. Note engine had not been started yet.
felt around in that area, very tight area hard to get ones hand in the area, the electric wiring felt hard, could be just the oil and dirt.
Started the engine and the temp dial when to high green just before red. buzzer may have gone off do not recall, if it did I pushed reset button and it quick buzzing; I dug a small trench 2 feet deep for 10 minuets and the buzzer did not go off but temp dial in high temp zone.
Radiator full of anti freeze coliant .
 

Nige

Senior Member
Joined
Jun 22, 2011
Messages
28,984
Location
G..G..G..Granville.........!! Fetch your cloth.
After just turning on the key (not starting the engine) the temp gauge moved from high to low, back and forth many times and buzzer when off, the engine did not even start yet.
OK, here's some info..........that's what's known as the "Self-Test". All the gauges swing full scale, the warning lights all flash, and the alarm buzzer goes off. Totally normal. You should keep an eye on the panel during this phase and if anything does not move, flash, or buzz - there's something wrong with it.....

It appears that you don't have an Operation & Maintenance manual. Did you know that you can download one for less than $50 from Cat.?

Back to check's post #2. Below is the water temperatiure sender (9). It is located on top of the engine where the upper water hose connects to the top of the radiator. Of particular interest should be the "spark-plug" type electrical connection on the top end of that sender.
upload_2019-10-17_9-16-57.png
 

parttimefarmer

Active Member
Joined
Apr 19, 2015
Messages
34
Location
minnesota
This is what I have done.
Installed a new CAT Water Temp Sensor.
Buzzer still comes on. Red light comes on, and thought out this process.
Idled machine one hour temp gauge when to middle of dial.
Shut off machine.
Turned on engine right away to see what would happen, the water temp gauge did not move from left side.
Buzzer came on.
Grounded the wire to the water temp senor to frame, the water temp gauge when to the far right side into the red zone far right side of it.
Plugged wire back on to water temp gauge.
Started machine buzzer went off. pushed reset button, buzzer goes off.
Water temp gauge does not move. Red warning light for water temp light comes on still..
Did a continutity test the wire from temp sensor to the dash water temp gauge is good.
Do I need a new Water Temp Gauge in the dash panel?
 

Cmark

Senior Member
Joined
Jan 2, 2009
Messages
3,176
Location
Australia
There are two separate sensors, one for the gauge, one for the light. The one for the light should be this one with two wires.

switch.jpg
 
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