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Ask Hank F. Your Own Question
Hank F.
Hank F., RV tech - emphasis on gensets
Category: RV
Satisfied Customers: 14489
Experience:  RV tech since the beginning of the millenium.
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I have a onan generator on my rv, just serviced will crank

Customer Question

I have a onan generator on my rv, just serviced will crank and gerate power but will only run 30 to 40 minutes and cuts off. gives me a service code saying it needs service
Submitted: 8 months ago.
Category: RV
Customer: replied 8 months ago.
have a fault code of 24
Expert:  Hank F. replied 8 months ago.

Hello, my name is ***** ***** I am going to assist you with this.

Code 24 on this unit is Coolant Temperature Sender Fault.

However, it is very odd that it would be showing a code 24. Code 24 is set within 5 minutes of starting the genset. For it to be running 30 or 40 minutes is very odd.

Are you seeing the code 24 right as it shuts down, or are you manually retrieving the code after shutdown?

Customer: replied 8 months ago.
Right after shut down
Expert:  Hank F. replied 8 months ago.

That is very odd.

The first thing I would do with this one in my shop would be to run it until it shuts down, and then immediately use an infrared thermometer to test the temperature of the thermostat housing.

I would suspect that the unit is running too hot, rather than having a faulty temperature sender. As I stated, a faulty temperature sender will cause the unit to shut down in 5 minutes - not 30 or 40.

While running, the thermostat housing should never get above about 232 degrees. If it does, it is overheating. The most common cause for overheating I see on this unit is a restricted radiator, indicated by a very high temp on the top tank, but a much lower temp on the bottom tank. I've got one in the shop right now that is showing a 105 degree difference between the tanks.

Expert:  Hank F. replied 8 months ago.

Was this what you wanted to know?

Expert:  Hank F. replied 8 months ago.

Was this what you wanted to know?