Engine overheat and derate

[Keith Moffett]

Two questions.

With the new steel surge tank and a new radiator cap, why doesnt the coolant bleed back to the overflow bottle?  The thermostats might be sticky?

Also, I was hitting about 215 deg. On the Silverleaf in the mountains on a warm day.  The analog guages read close to 230 deg.  So  which guage is used by the computer when it decides to derate the motor?

BTW, I did shift to 3rd. To keep it under 210 on the Si,verleaf and at the pass we sat for a few minutes and the Silverleaf got right down to 190 but the idiot guages were still at 210. 

Just makes me wonder .
Keith

[Lee Welbanks]

At that temp your should be full on, is your fan running on high speed? Radiator fins full of crap no air flow, thermostat stuck open.
I have never got my C13 up passed 205 on a hot day pulling wide open.

[Jerry Carr]

I have had temp issues since our major break down last year with the new fan (2 of these) and 3 Danforth wax Thermo valves we now run 194-207 the Danforth is rated at 199 this is correct for the C13 on our 06 PT

I used to run at 187 to 197. No one can tell way the difference but I have not seen an over heat since our return from PHX. If you hit the 230 range you should be getting an flashing or solid engine light also engine will de-rate.

I have been told the C-13 runs better in the 194-205 range and plan to watch it on the road to Branson.
   

[Steve Huber Co-Admin]

Keith,
Not sure where you are and what kind of grades you were pulling, but those temps sound excessive for a C12. Be sure the system is full of anti freeze. Also, take the tranny out of Economy mode and downshift to keep the temp down and RPMs up as Lee noted. Also, check/clean your radiator when you get a chance. If that doesn't help or radiator is clean, may be something mechanical, e.g wax valve or hydraulic pump.
Steve

[Gerald Farris]

Keith,
The correct engine operating temperature is the one displayed on the Silverleaf. That is the one that the ECM (engine control module) is using to control the engine, and derate it if necessary. Like I always say because of their questionable accuracy, the "analog dash gauges are for entertainment purposes only".

The 215 temperature reading is a little high for your model coach, regardless of outside temperature or hill climbing conditions. Are you sure that the cooling system is full of coolant? Low coolant level will also explain the lack of coolant transfer to the overflow bottle.

Gerald 

[Keith Moffett]

Yup, thanks all.  The radiator was cleaned outside and flushed inside a year ago with ELC added. 
When running down I 5 the Silverleaf reads 189 to 195 even towing.  We were going over White pass in Wa. To an elevation of about 4600 ft.  This is a small and windy road hwy 12 so speeds were slow.

There doesnt appear to be any leaks but the steel surge tank is always full from the over flow but not returning it to the bottle.  Just crack the cap and it spills a few ounces.  I am thinking a sticky thermostat.

Aparently the fan is kicking in because it will hit 195 or so and drop right down again.

Thanks
Keith

[Dave Atherton]

keith if you go to Branson in Sept. I can connect Cat ET to your motorhome and check out your
engine heating history. Dave Atherton Retired Cat Mechanic

[Keith Moffett]

Dave, thanks a bunch for the offer.  I would so take you up on that but we wont be in Branson.
Keith

[Larry Dedrick]

Keith:
            We had overheating problems on our 2001 Marquis Amethyst C12 as well. I had installed the metal reservoir and serviced it appropriately. When we left on our 2014 road trip, we had a small leak in our heater core for the driver and pass heat and did not realize this. As our travels continued, I started to see unusual temps but would settle to normal once we were rolling on the interstate. Eventually, the coolant got low enough in the radiator and our temp issues were compounded because the radiator fan probe was not sensing any fluid temp and therefore the fan would not operate appropriately. When we were experiencing the temp fluctuations, I had made sure the reservoir was full but did not continue to check everyday because it wasn't taking that much fluid. After the heater core was bypassed it took several days to get the coolant filled because the engine needs to heat up and cool down. On my last run to the cat dealer, the coach maintained an acceptable temp, but due to the temps I reached (225 deg.), I had them change the thermostat and engine oil and all was well. It took several days to fully top off the coolant even after the Cat tech was complete.
             I thought I was servicing the reservoir correctly but I should have been on top of it every cool down.
             As Gerald said, make sure the system is full.

              Good Luck              Larry D.

[Dave Atherton]

Gerald you said it in a nut shell. Analog Dash Gauges are for entertainment purposes only.
As our motorhomes are getting older and information of what is happening in the rear of
motorhome is ever important as we drive down the road. Having sliver leaf or Aladdin installed
Cannot be a better investment. What they have to offer will offset money outlay by being on
top minor problems that all is required in most cases stop and check what going on. Anyway
Very good review of analog gauges ( entertainment ) one stop at repair shop would pay for unit
on the road.  Dave