Overheating going uphill only?

[euphoria2me]

My 2005 Monaco Diplomat overheats only going up hill. Had the radiator and CAC removed and cleaned in Denver, changed the filter, radiator cap and checked for exhaust leaks but she still overheats going up-hill, not on flat terrain. She has a 400 ISL Cummins with 62000 miles. I'm running out of options. Any technical suggestions based on actual experience with this problem would be greatly appreciated. 

Edited August 3, 2020 by Euphoria2me
Added text

[jleamont]

Euphoria2me, Welcome to the FMCA Forums!

When you say its overheating, do you mean it boils over or just the temp gauge runs high? 

If just the gauge it could be inaccurate, ours climbs into the red often and when I look at the digital readout it never goes over 190 degrees.

How old is the radiator cap and what PSI is it?

Have you tried to downshift to raise the RPM's and see if that corrects the concern? 

Is the cooling fan running on HIGH while this is occurring,? You should be able to hear it roaring.

Edited August 3, 2020 by jleamont

[euphoria2me]

5 minutes ago, jleamont said:

Euphoria2me, Welcome to the FMCA Forums!

When you say its overheating, do you mean it boils over or just the temp gauge runs high? 

If just the gauge it could be inaccurate, ours climbs into the red often and when I look at the digital readout it never goes over 190 degrees.

How old is the radiator cap and what PSI is it?

Have you tried to downshift to raise the RPM's and see if that corrects the concern? 

Thank you for the welcome. Temp gauge shows 225+ and alarm goes off. As I indicated, the radiator cap was changed. Higher RPM's helps but does not solve the problem. I'm showing signs of excessive heat on engine door insulation. 

[jleamont]

What PSI cap and how old is the coolant? I know it was all pulled and cleaned the radiator and CAC but sometimes the old coolant will get reinstalled to save a few dollars. 

Can you hear the fan? This is a big one, Monaco had problems with the wax valve that controls the fan in those years. I don't recall what the problems were i.e. fan to aggressive or not aggressive enough. I believe it could go either way depending on what position it failed at. 

What are you using to monitor temperatures? I installed done of these and accurate readouts have made me not look at those old gauges. 

https://www.scangauge.com/products/scangauge-d/

This is the solution to a failed factory fan control wax valve.

http://sourcerv.com/conversion

 

 

[euphoria2me]

Much appreciated! Thanks!! 

PS. New fluid and cap. 

Edited August 3, 2020 by Euphoria2me

[jleamont]

Another thought. Replace the water pump with the newly designed for more water flow. Here’s an example of the difference. OEM Cummins is the only one making the new version.the old one is the all metal. 

[rayin]

Another possibility, Has the cooling system thermostat been checked or replaced? How is the lower radiator hose? If it is soft and squishy(technical term there) It can collapse when the water pump is working fast.

[wildebill308]

Euphoria2me, Welcome to the forum. Ithink Joe is on to something with the wax valve. The first thing I would do is see what the fan speed is when it is hot. I am betting it isn't locked at high speed. (one of the common problems)

Let us know what you find.

Bill

[euphoria2me]

Thanks for the advice. I will eliminate as advised until the problem is resolved.l 

[hermanmullins]

On 8/3/2020 at 12:07 PM, Euphoria2me said:

Higher RPM's helps but does not solve the problem. I'm showing signs of excessive heat on engine door insulation. 

With your above statement I would lean towards dirty Radiator and CAC. What that tells me is that it is trying to draw as much air across to radiators as it can but need more air flow and a clean radiator will give it that needed flow.

JMHO

Herman

[euphoria2me]

On 8/3/2020 at 5:38 PM, jleamont said:

Another thought. Replace the water pump with the newly designed for more water flow. Here’s an example of the difference. OEM Cummins is the only one making the new version.the old one is the all metal. 

I took your advice and installed the updated water pump. We'll see if that helps. Thanks!

[wildebill308]

Have you checked if the fan is going to hi speed when the temps are up?

Bill

[manholt]

I had that same issue on a 2007 WB Tour 40' with a Cummins 400.  My engine cooling tank was half the size it was suppose to be...replaced by WB because their end cap would not fit over the original chassis!  I lived with the yellow light coming on in the NM, CO, WY, mountains every year.  Downshift to 5 or 4 did help...rear radiator.

[papabee49@hotmail.com]

Just curious, is there a preference to side vs rear radiator, which one performs better?

[hermanmullins]

Definitely if you like to do your own work, a side radiator is best.

Herman 

[papabee49@hotmail.com]

I have no diesel experience so doing my own work is questionable

[TimeTraveler]

We have C7Cat in an 05 Revolution. Cac and Radiator partially clogged. At 220 degrees it would defuel and creap along and sound the alarm Freightliner cleaned them two weeks ago....but taking it out of the shop here in Kingman Az thy circled the building loading it up with dust.Wife drove it down the rod with me following. i thought it was on fire at first. Rear radiator and it vaccuums everything off the road. Hosed it off and all is good but....t does run hotter on biodiesel.It still gets near 215-218 degrees up hill on I4o in thin air at Seligman on to Flagstaff.

First trips west from 2006 2007 problems...and  UlSD not here yet and biodiesel was not even on thee horizon. I wish  I could find some old LSD this engine was designed for.

[wildebill308]

1 hour ago, TimeTraveler said:

It still gets near 215-218 degrees up hill on I4o in thin air at Seligman on to Flagstaff.

When it does that I would downshift to 5th or 4th gear.

I also run Diesel Kleen in every tank.

Bill

[dickandlois]

22 hours ago, TimeTraveler said:

We have C7Cat in an 05 Revolution. Cac and Radiator partially clogged. At 220 degrees it would defuel and creap along and sound the alarm Freightliner cleaned them two weeks ago....but taking it out of the shop here in Kingman Az thy circled the building loading it up with dust.Wife drove it down the rod with me following. i thought it was on fire at first. Rear radiator and it vaccuums everything off the road. Hosed it off and all is good but....t does run hotter on biodiesel.It still gets near 215-218 degrees up hill on I4o in thin air at Seligman on to Flagstaff.

First trips west from 2006 2007 problems...and  UlSD not here yet and biodiesel was not even on thee horizon. I wish  I could find some old LSD this engine was designed for.

Had the same problem with a Cummings engine, Cleaned everything and asked Service center to replace the Thermostat. It had failed mechanically with mettle failure .  A  unusual  issue , but it does happen.  

Rich.

[manholt]

Rich, do you have 2, or just one?  I'v had both fail, so now I replace each time I flush mine out.  

I prefer side radiator.  

[dickandlois]

Carl, The coach has just one in our case!

Rich.

[fly2low]

I found that switching to synthetic motor oil helped mine run cooler.  Kind of a last ditch cure as 30+ qts of T6 makes for an expensive oil change

[wildebill308]

4 hours ago, fly2low said:

I found that switching to synthetic motor oil helped mine run cooler.  Kind of a last ditch cure as 30+ qts of T6 makes for an expensive oil change

I run T-6 well worth the cost. My coach takes 40 Qt + the generator. 

Those ar 2 1/2 gal jugs.

Bill

Edited August 20, 2020 by WILDEBILL308

[rayin]

I'm feeling really good about my side-radiator Spartan chassis right now. It's never overheated-anywhere, which means I don't need to spend money on synthetic oil for that reason. I just flush out the fins once a year with a water hose.

[wildebill308]

1 hour ago, RayIN said:

I'm feeling really good about my side-radiator Spartan chassis right now. It's never overheated-anywhere, which means I don't need to spend money on synthetic oil for that reason. I just flush out the fins once a year with a water hose.

I didn't do it because I was overheating. Having run a oil lab in my past I believe in running the best oil to protect my investment. 

I now am running a K2 Spartan with a ISM Cummins.

Bill