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going2 · 05-23-2022, 10:22 AM

I have a 2004 Newmar on a W22. I have had the Actia Instrument Cluster refurbished by Brazels. I replaced the thermostat with a new OEM ACDELCO 195 deg. I got new temp sensor, water pump, & fan clutch from workhorseparts.com. The temp gauge has started acting wacky. If I start it up and drive it all seems normal. But if I shut it off for a few seconds and then turn the key back on the temp gauge all of a sudden shows MUCH higher.
I connected an OBDll and watched the temp on there comparing it to the dash gauge. I started the engine and let it get up to 150 deg. The gauge showed about half way up to normal operating temp. I shut off the engine. 5 sec later I turned the key on and the temp gauge went right back where it was. BUT I turned the key off and 15 sec later I turned the key back on and the gauge went to half way between normal and hot (red). The OBDll was still showing less than 160 deg. I turned the key off and 15 sec later I turned the key back on and the gauge went to beyond hot. I turned the key off and 15 sec later I turned the key back on and the gauge went to WAY BEYOND hot. I turned the key off and 15 sec later I turned the key back on and the gauge went as for as it could go in the counter clockwise direction, almost 360 deg rotation from the cold position. The whole time the OBDll stayed around 160 deg.
I did the Cluster Diagnostics Gauge Test. The Temp Gauge was perfect, 0%, 50%, 100%. I pulled the 2 connectors off the back of the instrument cluster and reseated them a couple of times.
Some people on this forum have said that this workhorse has 2 temp sensors, one for the ECU and one for the Temp Gauge. Is this true? I can’t find any info that verifies this. Does anyone know what is causing this problem? I am going to follow ktoutoor example and install the digital temp sensor with alarm but I would like to get the Cluster Temp Gauge working properly.
Thank you for your help
Christopher

Kahoona · 05-23-2022, 10:49 AM

This is interesting. I bet it does have two sensors in different places. It s normal for the temperature in a large engine to skyrocket when the coolant stops circulating. The heat is no longer being carried away. This "Heat Soak" is not good for the engine but is accepted and planned for. If you had one sensor near the radiator and one in the engines block area you would see 2 different curves upon shut down. The radiator area would perhaps go up a little but would roll off quickly. The block area would begin to rise and would peak far higher and later than the radiator area.

There are variables too- If the radiator fan continues to run the heat would drop fast in that area. If the engine has an electric water pump and it continues then both will drop evenly. (these were used on race motors but are more common now).

I could be way off here but it's a thought. Those who remember older V8's will remember that they were hard to start if you parked in front of the store, ran in and came out. They had overheated while they were off without fuel pump or fan on.

edgray · 05-23-2022, 03:52 PM

Going2: I suggest you talk to Jon or Alan at URVP about what you are seeing because they will stand behind their work.
FYI, the service people at WCC admitted years ago that the cluster “gauge” is PROGRAMMED to point to the mid-point almost always, unless there is a REALLY high coolant temperature. They admitted that this was done because their engineering people believed that some owners would not understand that a pressurized system isn’t boiling when a real gauge could be showing more than 212*F.

going2 · 05-23-2022, 06:33 PM

Thank you for your replies. I plan to call URPV tomorrow. Hopefully they are familiar with the problem.
Christopher

going2 · 05-24-2022, 12:01 PM

Update; I talked to Alan at URPV. He said that he is pretty sure it’s a bad stepper motor. He said that’s the way a bad stepper motor acts. Their records show that I got a LCD display screen replacement but no record of replacing the stepper motors. I can’t find any records on my end and now I’m starting to doubt my memory. It’s been at least a couple of years ago. Maybe I just got a screen replacement.

George Schweikle · 05-26-2022, 07:25 AM

I'm not surprised. The same has been acknowledged by manufacturers for oil pressure gauge readings. That's why I rely on engine data using information from the OBD2 port; reading with a Scangauge & OBD Fusion on a tablet.

Quote:

Originally Posted by edgray

....FYI, the service people at WCC admitted years ago that the cluster “gauge” is PROGRAMMED to point to the mid-point almost always, unless there is a REALLY high coolant temperature. They admitted that this was done because their engineering people believed that some owners would not understand that a pressurized system isn’t boiling when a real gauge could be showing more than 212*F.

Kahoona · 05-26-2022, 09:28 AM

Quote:

Originally Posted by edgray

Going2: “gauge” is PROGRAMMED to point to the mid-point almost always, unless there is a REALLY high coolant temperature. They admitted that this was done because their engineering people believed that some owners would not understand that a pressurized system isn’t boiling when a real gauge could be showing more than 212*F.

True! In fact, many temperature sensors and oil gauges are now only switches connected to dials that either read good or not. We recently paif $2000 to have a $49 oil pressure switch replaced. The engine shut down was also activated and it would not run until the entire onan generator was removed from the RV and dismantled to get to the switch.

1972VWbus · 06-03-2022, 02:43 PM

Quote:

Originally Posted by Kahoona

True! In fact, many temperature sensors and oil gauges are now only switches connected to dials that either read good or not. We recently paif $2000 to have a $49 oil pressure switch replaced. The engine shut down was also activated and it would not run until the entire onan generator was removed from the RV and dismantled to get to the switch.

The fix for the oil sensor on the Onan is to get rid (disconnect) of the wire to the oil sender (bottom of generator). Or spend the $money$ to replace the sensor.

As for the dash temperature gauge the early P series chassis caused many owners headaches due to their dancing wildly. Normal behavior for those units. 454 TBI units ran normal temps of 195 - 240ish

Kahoona · 06-05-2022, 09:48 AM

Quote:

Originally Posted by 1972VWbus

The fix for the oil sensor on the Onan is to get rid (disconnect) of the wire to the oil sender (bottom of generator). Or spend the $money$ to replace the sensor.

As for the dash temperature gauge the early P series chassis caused many owners headaches due to their dancing wildly. Normal behavior for those units. 454 TBI units ran normal temps of 195 - 240ish

Yes! We had a 120v 4000k which I eventually learned to overhaul. While it was out I wanted to replace the infamous oil sensor and did a bit of head scratching trying to locate it. Turns out that my model did not have one. It had a very rudimentary brain. Our 9k 240v diesel had the same problem and I spent the $2300 to have the generator pulled out and torn down to get to the sensor and replace it. If I had known that it would run if I disconnected the sensor I might have tried that. It has a lot more brains than the 4000 though.