I ran the Barth today. The low coolant alarm went off. There are no leaks and the overflow tank is full. Could this be the low coolant sensor? Where is it located on a Cummins 5.9 (1993 chasis)?

I had that happen to me one time last summer; for no apparent reason ...checked everything and ALL looked within normal limits.

I turned-on the dash heat to help cycle fluid thru the system and the alarm quit, nearly immediately. The alarm did not sound again after that one incident.

??? any suggestions - I'm no mechanic ???

I can't comment on where the Cummins Low Fluid sensor might be, but on my AMG/GM-powered coach, the sensor is in the top surge tank (oddly enough,a Ford part...), which is a plastic tank on top of the radiator.

quote:

Originally posted by Rusty:
...but on my AMG/GM-powered coach, the sensor is in the top surge tank...

I would suspect that it's on top of the surge tank too.

Remove it and check for slime, oil or calcium deposits. If you see this you should properly flush and refill your coolant system in addition to replacing the sensor.

Could a bad/corroded connection cause this???

quote:

Originally posted by Richard_Muise:
Could a bad/corroded connection cause this???

It COULD... but...

Normally a broken wire will keep it running and only a check engine light will come on to warn you.

But it also depends on how it's programmed.

Hmmmm, on my Breakaway, I don't have a surge tank, I only have a plastic catch tank and there is no low coolant level switch on it.

I will have to check now to find out if I have anything that could sense low coolant. I wish that the alarm panel would have a "self check" mode either on start up or a button that could be pushed to verify that all systems are go! All I got so far is low air and low engine oil pressure light at start up.

Will report back what i find.

quote:

Originally posted by MWrench:
Hmmmm, on my Breakaway, I don't have a surge tank, I only have a plastic catch tank and there is no low coolant level switch on it.

Richard has a 1994 Breakaway, just like you do. He has not contributed to the data tag yet, so I don't know if his was built after yours or not.

I would suspect that it is based on the low coolant shutdown feature. Unless of course, it was an added or upgraded item.

On my Regency the Gillig Manual has an electrical schematic. It shows TWO water temp coolant alarms - if you have a similar coach and a schematic look for rear and front coolant switches. I am guessing that this is because there are two heaters that use the coolant - one in the rear and one under the couch behind the driver. By cycling the Aux Heater you filled the lines and radiator and solved what was not a problem but now you know it works.

I didn't see anything on the expansion tank but I noticed an electrical plug on the left side of the radiator about 3 inches down from the top. It's connected to a screw in cylindrical device. Could that be it?

Rick

That's likely it.

quote:

Originally posted by Richard_Muise:
I didn't see anything on the expansion tank but I noticed an electrical plug on the left side of the radiator about 3 inches down from the top. It's connected to a screw in cylindrical device. Could that be it?

Rick

I just checked my rad and found that there is a sensor on the side just like yours! DUH! I have changed the rad but forgot about that sensor.

I did unplug it and turned the key on but got no alarm,tomorrow I will start it and see if it shuts down when removing plug, if that doesn't work, I'll short the connections to see if it shuts down the engine (or turns on the low coolant light) and report back.

Rusty is right, if there is a sensor that is where it would be.

I am feeling deprived, here, since my lowly Pee thirty-something does not have a low coolant warning.

Has anybody ever put one on a vehicle? I think I remember having one on an Olds 98 a while back.

Does anyone know the procedure for changing this sensor?

You would have to drain a bit of coolant, probably no more then a gallon, to get the coolant below the sensor position, and then unplug the sensor, back it out, replace with new using new gasket, IIRC it is a copper ring.

Reconnect the wiring, fill back up. Make sure you have coolant in the overflow tank, about 1/2 full and then run until up to full operating temperature, wait over night and check/top off the radiator again, get all the air out with some hot/cold cycling.

HTH