Engine water temp-What is considered high?

[frankiebIII]

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!

[11178adm]

I am surprised you didn't get a check engine light at 230.
after a trip to Yuma and Utah in June I had overheat issues found a lot of grass, leaves, dirt and two mud dauber nest on the face of the coolant radiator, removed the cac and was able to use compressed air and a pressure washer to clean it out. a trip to Arkansas in 98 degree weather in late July and no overheat. you can not see the dirt on the face of the coolant radiator without a bore scope of some sort or removing the cac. this is a fairly common problem as the cac has larger openings and everything passes through it and gets caught on the face of the coolant radiator

[YC_1]

If the thermostat has never been replace, do it. Clean the radiator. I traveled the vine a couple of times in the RV and the last time (3 yrs ago0, the temps went above normal. A new thermostat that was new and improved has been running since. Many thousands of miles and hills. Thermostats are cheap,.

[usersmanual]

frankiebIII wrote:
Thank you for all the replies. A few things and more questions.
1. I am not very knowledgable when it comes to engines and don't do my own work so Usermanual I'm don't add more fluids and I don't know what an HP hose is.
2. I only put about 2500 miles a year MAX on the motorhome and get it serviced once a year although it has been a year and a half since last service.
3. When the temp hit 225-30ish and I hear the beeping sound i'm only at that temp for about 5-10 mins max before the grade levels out and the temp quickly drops.

What is the gear I should be in to climb the Grapevine grade?

Perhaps have one make sure your not low on coolant then if that's the case
HP= High Pressure water hose
4th gear at max and 3rd gear maybe depends on how hard u hit the bottom.I like to hit those climbs at like 75MPH so I can and make it part way before putting a load on my unit and having to shift down
5-10 minutes is nothing

[frankiebIII]

Thank you for all the replies. A few things and more questions.
1. I am not very knowledgable when it comes to engines and don't do my own work so Usermanual I'm don't add more fluids and I don't know what an HP hose is.
2. I only put about 2500 miles a year MAX on the motorhome and get it serviced once a year although it has been a year and a half since last service.
3. When the temp hit 225-30ish and I hear the beeping sound i'm only at that temp for about 5-10 mins max before the grade levels out and the temp quickly drops.

What is the gear I should be in to climb the Grapevine grade?

[Ivylog]

Yes
Yes
Yes
Manually gear down to get your RPMs up.

[Sam_Spade]

wolfe10 wrote:
I would no run over 210 or so.

Bad advice.

Or unnecessarily conservative at least.

Most all engines will cruise along all day at 220.
Most don't run quite that hot but they easily can.

The other advice about downshifting and turning off the A/C if necessary is spot on.

The truckers know what they are doing......but the ones going VERY SLOW are heavily loaded.

P.S. The rule of thumb is: You should go back DOWN the mountain in the same gear as the one you used to go UP.

[J-Rooster]

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]

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]

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]

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]

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]

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]

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]

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]

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.