Hi all, I have a 2005 Monaco Diplomat with a 400 hp Cummins diesel, I have owned it for 4 years. It has been problem free and runs great. However, the 4 times I have taken it over the Grape Vine steep grade the engine water temp creeps up over the 200 marker. When it gets to about 225 I start to hear a faint squelching/light beeping sound from by my left leg. As it gets to about 230ish it becomes a full blown beeping sound like when a car door is left open on an automobile. No warning lights come on and my RV is equipd with a engine warning light, a check engine light and a Stop Engine light. As I go down hill the beeping slowly fades as the engine cools until it goes to a light squelch and then disappears. I am assuming this is some sort of warning. Is it a warning?Does anyone else get this warning?Is my engine running too hot?What can I do to bring the temp down when going up a hill as I do have the peddle all the way down? Should I drop my speed to a crawl like the semis do?Should I pull over and let engine cool and if I do that do I rust sit and let it idle or turn off engine after it idles a few mins?Thanks for any education you can offer!

Drop down a gear or two to keep the rpms at 2000 to 2500. Might get radiator cleaned. Pull over to the side and run at Fast idle 1100rpm. Do not shut engine off unless temp does not come down.

With proper mix and pressure you should not boil until over 265.By all means check the cooling system or slow down a bit.I would not pull over unless the trouble continued at half speed or boil over seems inevitable. Not familiar with the warning system.

I would no run over 210 or so.As Jerry said, gear down, back out of the throttle a little. With the ISL, 2100 is peak HP. Governed redline is 2330. So, settle in at 2000 to 2100 RPM.Be sure the dash A/C is OFF (minimum of 5 HP additional load-- if A/C condenser is in the "cooling package" you are now using super heated air to cool the CAC and radiator).We are just finishing up a 3000 mile trip-- same engine. Never saw coolant temperatures over 202 degrees F. As coolant temperature approaches the 200 mark, I am proactive to keep it from rising.

My 6.0 Ford Diesel runs at about 205 on flat roads when I'm towing. When it gets above 220 I back out of the throttle. The fan on my truck is set to come on when the temperature reaches 210 and that usually keeps the temperature from getting much higher.You might be hearing the fan or a slipping fan clutch.

mabynack wrote:My 6.0 Ford Diesel runs at about 205 on flat roads when I'm towing. When it gets above 220 I back out of the throttle. The fan on my truck is set to come on when the temperature reaches 210 and that usually keeps the temperature from getting much higher.You might be hearing the fan or a slipping fan clutch.Totally different engine (Ford 6.0 vs Cummins 8.9) and totally different cooling/fan control (clutched fan front radiator vs hydraulic fan side radiator in rear).

Engine water temp-What is considered high? | Good Sam Community

J-Rooster
Explorer
Aug 29, 2016
Frankie, I drove diesels all my working life and I've heated a couple of those engines up a few times. I'm retired now but when I was working are mechanic told me one time not to make a habit out of heating motors up on a hard pull, downshift! And the wrench also told me that 212* is boiling but, diesels can run hotter than that on a well pressurized cooling system and not damage the motor. How much hotter I don't know?
wolfe10
Explorer
Aug 29, 2016
A case of "best practices" vs "what I got away with".

With just a little change in driving technique, one can easily move to/toward "best practices".

And, if a rear radiator, also an annual cleaning of the FRONT of the Charge Air Cooler!
rgatijnet1
Explorer III
Aug 29, 2016
What may also be of some concern is that when the engine temperature goes up, the transmission fluid also gets hotter. Best to keep them both lower.
usersmanual
Explorer
Aug 29, 2016
frankiebIII wrote:
Hi all,
I have a 2005 Monaco Diplomat with a 400 hp Cummins diesel, I have owned it for 4 years. It has been problem free and runs great. However, the 4 times I have taken it over the Grape Vine steep grade the engine water temp creeps up over the 200 marker. When it gets to about 225 I start to hear a faint squelching/light beeping sound from by my left leg. As it gets to about 230ish it becomes a full blown beeping sound like when a car door is left open on an automobile. No warning lights come on and my RV is equipd with a engine warning light, a check engine light and a Stop Engine light. As I go down hill the beeping slowly fades as the engine cools until it goes to a light squelch and then disappears. I am assuming this is some sort of warning.

Is it a warning?
Does anyone else get this warning?
Is my engine running too hot?
What can I do to bring the temp down when going up a hill as I do have the peddle all the way down? Should I drop my speed to a crawl like the semis do?
Should I pull over and let engine cool and if I do that do I rust sit and let it idle or turn off engine after it idles a few mins?

Thanks for any education you can offer!

the noise u hear is a factory overheat beeper. 230 is hot.For a short distance no problem,Big question is R U having to add fluids after this or not.Grapevines a long hard pull best to select 4 th gear or 3 rd gear and just slowly pull your way to the top running in the 2-21 rpm area.maybe try running a HP water hose through the CAC and side mounted rad. maybe getting pretty dirty
Have you ever stopped and made sure the fans running full RPM when getting these high temps?
sch911
Explorer
Aug 29, 2016
For my job we routinely run truck with trailer towing tests in the southwest US. The engine coolant abort temperature (the point where we stop the test) is 250F. In my DP I see similar temps like what you have. Doesn't worry me a bit!
wolfe10
Explorer
Aug 29, 2016
mabynack wrote:
My 6.0 Ford Diesel runs at about 205 on flat roads when I'm towing. When it gets above 220 I back out of the throttle. The fan on my truck is set to come on when the temperature reaches 210 and that usually keeps the temperature from getting much higher.

You might be hearing the fan or a slipping fan clutch.

Totally different engine (Ford 6.0 vs Cummins 8.9) and totally different cooling/fan control (clutched fan front radiator vs hydraulic fan side radiator in rear).
mabynack
Explorer II
Aug 29, 2016
My 6.0 Ford Diesel runs at about 205 on flat roads when I'm towing. When it gets above 220 I back out of the throttle. The fan on my truck is set to come on when the temperature reaches 210 and that usually keeps the temperature from getting much higher.

You might be hearing the fan or a slipping fan clutch.
wolfe10
Explorer
Aug 29, 2016
I would no run over 210 or so.

As Jerry said, gear down, back out of the throttle a little. With the ISL, 2100 is peak HP. Governed redline is 2330. So, settle in at 2000 to 2100 RPM.

Be sure the dash A/C is OFF (minimum of 5 HP additional load-- if A/C condenser is in the "cooling package" you are now using super heated air to cool the CAC and radiator).

We are just finishing up a 3000 mile trip-- same engine. Never saw coolant temperatures over 202 degrees F. As coolant temperature approaches the 200 mark, I am proactive to keep it from rising.
time2roll
Nomad
Aug 29, 2016
With proper mix and pressure you should not boil until over 265.
By all means check the cooling system or slow down a bit.
I would not pull over unless the trouble continued at half speed or boil over seems inevitable.
Not familiar with the warning system.
Mandalay_Parr
Explorer
Aug 29, 2016
Drop down a gear or two to keep the rpms at 2000 to 2500.
Might get radiator cleaned.
Pull over to the side and run at Fast idle 1100rpm. Do not shut engine off unless temp does not come down.

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