High temp coolant alarm

[jrburch1946]

On a recent trip thru the rockies , the high temp buzzer and light came on although the gage was only showing 210 degrees with engine showing no signs of overheating. When watching the gauge temp in relation to alarm/ light it appears that the alarm/light starts to comes on at approximately 200 with full brightness and sound at 210. I believe 200 is too low setting. Are there 2 sending units on the engine cooling system? 1 for the buzzer / light and 1 for the guage or is there 1 common sensor.

This is a 1997 Holiday Rambler Imperial, 8.3 c Cummins 330hp

Thanks to all who can help.

[Skip426]

There is every possibility that the chassis or coach manufacturer , has added a second sensor for the gauges , and that the Cummins sensor is defective, but , without attaching a scan tool to the engine ECM for a read out to confirm, what the ECM is seeing for temps and comparing to a read out using an infa-red thermometer on the thermostat housing , you can't tell which sensor is giving a correct reading.

Cummins coolant temp sensor is beside the t'stat housing, upper rad hose connection.

[GA Navigator]

Originally Posted by jrburch1946

On a recent trip thru the rockies , the high temp buzzer and light came on although the gage was only showing 210 degrees with engine showing no signs of overheating. When watching the gauge temp in relation to alarm/ light it appears that the alarm/light starts to comes on at approximately 200 with full brightness and sound at 210. I believe 200 is too low setting. Are there 2 sending units on the engine cooling system? 1 for the buzzer / light and 1 for the guage or is there 1 common sensor.

This is a 1997 Holiday Rambler Imperial, 8.3 c Cummins 330hp

Thanks to all who can help.

I had the very same thing happen this past summer. Same temps as you describe. The first time the buzzer was just barely chirping and I couldn't figure out what the noise was. I've never had any prior temp problems but those are some massive hills in Colorado.
I don't know if there are two sensors or one.


1994 Holiday Rambler Navigator
Cummins 8.3
Allison MD3060