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Topic: Cummins M-11 450 Engine Overheating (Read 1488 times) previous topic - next topic

Cummins M-11 450 Engine Overheating

After replacing the Thermostat in Flagstaff & the Radiator in Denver. See Thread:
What did you do to your coach today.
I was still overheating on the way to Cody.
I kept noticing my Coolant overflow bottle was not moving up or down with the temperature.
I wasn't sure if that would be reason enough for me to be overheating.
But after some online searches it appeared it could be part of the reason.
I found my radiator cap had a tear in the gasket.
So I traded radiator caps with one of my traveling companions.
Mine was rated 15 and the other was 10.
For the next 60 miles it appeared to act more normal.
I got a new cap in Cody and will see if the problem is solved on the way home.
I think the radiator leak was a coincidence and needed replacing but the thermostat may have not needed to be replaced.
The selected media item is not currently available.Barry BEAM #16014
2003 U320 40' AGDS
Beamalarm, Foretravel technical help and specifications
"Whatever the mind can conceive and believe, it can achieve"

Re: Cummins M-11 450 Engine Overheating

Reply #1 –
Barry,

If the level of the coolant does not change cold vs hot, it indicates that there is air in the cooling system.  The air is absorbing the expansion of the coolant as it heats up.  If you only have liquid in the cooling system, it is non-compressible and will raise the level in the overflow bottle.

When cold, remove the radiator cap and top off.  Repeat until the level in the overflow reservoir rises when coolant is hot.

Brett
Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020

Re: Cummins M-11 450 Engine Overheating

Reply #2 –
There may be a air bleed petcock at the highest point in the cooling system on the M-11. This insures that all the trapped air gets out so there is only coolant in the system. On some installations, the radiator cap or reservoir is not the highest point in the system.

Any M-11 operators out there that may have had this problem?

Pierce
Pierce and Gaylie Stewart
'93 U300/36 WTBI
Detroit 6V-92TA Jake
1140 watts on the roof
SBFD (ret)

Re: Cummins M-11 450 Engine Overheating

Reply #3 –
The other Brett is correct.  The radiator cap is the highest point in the FT M-11 installation.  You would know if the radiator cap gasket had indeed failed.  You would see coolant all over your toad.  Don't ask.
Regards,
Brett

'99 42' Foretravel Xtreme
'14 Brown Motorsports Stacker
'05 Chevy SSR
'02 BMW R1150R

Re: Cummins M-11 450 Engine Overheating

Reply #4 –
I just had to drain my system to replace a hose. when I re-filled it to my surprise it filled completely on the first fill. I checked after the first couple stops and the level stayed full. (proper) So it seemed to have purged all of the air while filling from the radiator cap.
1999 U320
Mount Dora Fl

Re: Cummins M-11 450 Engine Overheating

Reply #5 –
Quote from: wolfe10 –
Barry,
If the level of the coolant does not change cold vs hot, it indicates that there is air in the cooling system.  The air is absorbing the expansion of the coolant as it heats up.  If you only have liquid in the cooling system, it is non-compressible and will raise the level in the overflow bottle.
When cold, remove the radiator cap and top off.  Repeat until the level in the overflow reservoir rises when coolant is hot.
Brett
That makes good sense Brett, but not sure how it would get an air bubble?
Up until this trip the overflow tank had been showing rise and fall of the coolant.
I have had no fluid leaking in my driveway from the newly found radiator leak which leads me to believe it had just started and was very small.
When I took off the old radiator cap the engine was still warm but safe to take off cap.
Coolant was at the top of the filler neck leading me to believe it was full. (false assumption)
After replacing the radiator cap the overflow tank was now moving after we stopped in campground.

SOOO, there are 4 of us here that want to rationalize what we are seeing for a learning experience.

1. It appears that I had an air bubble before I replaced the radiator however it got there.

2. I had an air bubble after the radiator replacement, possibly after running the engine the tech saw the overflow bottle with coolant in it and believing the coolant was full.

3. The radiator cap had a torn gasket and was not creating the vacuum needed to draw the coolant in after the engine cooled?

4. Checking the level of coolant before engine fully cooled gave a false assumption.

5. After replacing the radiator cap and letting the engine cool fully in the campground,  it did swallow the entire overflow bottle indicating it was indeed low as Brett suggest.

I will fill the coolant to proper level and monitor it on the way home next week with the new radiator cap.

Brett, thanks for the phone support.

The selected media item is not currently available.Barry BEAM #16014
2003 U320 40' AGDS
Beamalarm, Foretravel technical help and specifications
"Whatever the mind can conceive and believe, it can achieve"

Re: Cummins M-11 450 Engine Overheating

Reply #6 –
Quote from: Barry Beam –

Brett, thanks for the phone support.

You are welcome.  A little bazaar-- we were just getting off an Alaska cruise in Seward AK when I got your call.

Did you get a chance to determine how to force the fan to high speed?  Verify that as coolant temperature gets a few degrees above thermostatic control that it does kick to high speed?

Brett
Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020

Re: Cummins M-11 450 Engine Overheating

Reply #7 –
Quote from: wolfe10 –
You are welcome.  A little bazaar-- we were just getting off an Alaska cruise in Seward AK when I got your call.

Did you get a chance to determine how to force the fan to high speed? 

Brett
Yes,
Per Mark Harvey, You disconnect the cable to the Sauer Danfoss 1090273 fan control module to default to high speed.
I have not had the chance to try it yet. But will if problem persists.
The selected media item is not currently available.Barry BEAM #16014
2003 U320 40' AGDS
Beamalarm, Foretravel technical help and specifications
"Whatever the mind can conceive and believe, it can achieve"

Re: Cummins M-11 450 Engine Overheating

Reply #8 –
Barry,

Where is the fan control?
John Duld
1995 U320C SE 40'

Re: Cummins M-11 450 Engine Overheating

Reply #9 –
Quote from: John Duld –
Barry,

Where is the fan control?

See photo above. In my 2003, it is in the lower right in the engine compartment.
Yours may be different.
The selected media item is not currently available.Barry BEAM #16014
2003 U320 40' AGDS
Beamalarm, Foretravel technical help and specifications
"Whatever the mind can conceive and believe, it can achieve"

Re: Cummins M-11 450 Engine Overheating

Reply #10 –
Quote from: Barry Beam –
Yes,
Per Mark Harvey, You disconnect the cable to the Sauer Danfoss 1090273 fan control module to default to high speed.
I have not had the chance to try it yet. But will if problem persists.

Barry,

That is what I thought and told you, but did not have access to any manuals in Alaska.

Brett
Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020

Re: Cummins M-11 450 Engine Overheating

Reply #11 –
As a final thought. I bought a replacement radiator cap for myself & a 10 psi for BJ Holden for her coach since I borrowed hers for testing.
After inspection we noticed mine had a second gasket around the rim but hers did not.
Calling around to get some answers we finally got some info on the internet that if you have a coolant recovery system you need that second gasket.
Radiator Caps
My 15 part number is Napa 703-1427
All ready for testing on the way home 8)

Napa did not have a 10 with the gasket so we found one at Carquest Part # CCA 33022

The selected media item is not currently available.Barry BEAM #16014
2003 U320 40' AGDS
Beamalarm, Foretravel technical help and specifications
"Whatever the mind can conceive and believe, it can achieve"

Re: Cummins M-11 450 Engine Overheating

Reply #12 –
Since the advent of cooling system overflow bottles, radiator caps have two different spring-loaded parts, each with their own gasket and spring. There is a third gasket that keeps the cap tightly sealed all the time on the top lip. Cap must be rotated closed all the way to the stop for this third seal to work.

An inner gasket with a strong spring opens to let expanded coolant out and the number on the cap represents the maximum internal PSI of the cooling system before the cap opens. This is the gasket that seals against the radiator housing inside flat 'shelf'. Over pressure moves coolant from coolant system to overflow bottle.

A small spring loaded gasket is in the center of the cap and is held tightly closed when the cooling system is under any pressure. When the cooling system cools it starts to draw a vacuum and the center will open at the slightest vacuum as it is held closed with a very light spring. Under vacuum, coolant moves from overflow bottle to coolant system.

The hose from the radiator housing to the overflow bottle must be air tight so as to not suck air back in during the cooling phase and capture all overflowed coolant.

Re: Cummins M-11 450 Engine Overheating

Reply #13 –
Quote from: Barry Beam –
Yes,
Per Mark Harvey, You disconnect the cable to the Sauer Danfoss 1090273 fan control module to default to high speed.
I have not had the chance to try it yet. But will if problem persists.
After I left Cody with new Radiator Cap and fluid topped off, I still had the temperature climbing quickly when I accelerated uphill. I unplugged the fan control to default it to the higher speed.
After 90 miles with lots of climbing and high outside temps it was finally acting correctly.
I was going to replace the fan control until I looked at the plug :o
It had some white stuff all over it. I wasn't sure if it was corrosion or coolant overflow (my guess)
So I proceeded to clean the plug pin inserts with a dental proxybrush 8)
Plugged it back in and drove home from Las Vegas. Climbing the hills it worked much better.
Hopefully that solves the cooling issue with a new Radiator, Radiator Cap, coolant, Thermostat and clean fan control.
The Cody Rally ended up costing a little more than what I had budgeted but AHHH, do I know this cooling system inside and out now.
We decided to fly to Cancun next week for a family gathering and let someone else do the maintenance on this trip. ::)
The selected media item is not currently available.Barry BEAM #16014
2003 U320 40' AGDS
Beamalarm, Foretravel technical help and specifications
"Whatever the mind can conceive and believe, it can achieve"

Re: Cummins M-11 450 Engine Overheating

Reply #14 –
Barry,

De Oxit is a great product for cleaning those connections: Home of DeoxIT® and HAND-E-GLOVE® - CAIG Laboratories, Inc.

And, don't replace the controller until you have proven that it does not work properly with that electrical connection cleaned up.

"Not working properly" is defined as coolant temperature rises a few degrees above thermostatic control and then fan switches to high and brings it back down to thermostatic control at which time fan switches back to low speed.  Repeat.......

Yes, forcing it to high fan speed will cure the overheating is fan speed is the culprit, but you are paying more in diesel to turn that fan on high (takes more HP).

Brett
Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020

Re: Cummins M-11 450 Engine Overheating

Reply #15 –
Quote from: wolfe10 –
Barry,

De Oxit is a great product for cleaning those connections: Home of DeoxIT® and HAND-E-GLOVE® - CAIG Laboratories, Inc.

And, don't replace the controller until you have proven that it does not work properly with that electrical connection cleaned up.

"Not working properly" is defined as coolant temperature rises a few degrees above thermostatic control and then fan switches to high and brings it back down to thermostatic control at which time fan switches back to low speed.  Repeat.......

Yes, forcing it to high fan speed will cure the overheating is fan speed is the culprit, but you are paying more in diesel to turn that fan on high (takes more HP).

Brett
Thanks Brett, That was my next thing to do. I have some electric contact cleaner here at home.
Since it appears to be working I wont be replacing the fan control.
When I forced the fan to high speed I did see it taking its toll on the mileage over 90 miles.
But I was glad you gave me that option as a backup to try.
Lots of steep climbs that I dont think I would have made in the heat without that fan working on high.
Getting out of cruise control, dropping down to 4th gear and then to 3rd when necessary climbing the hills really made a difference in controlling the temperature also.
The VMSpc was so useful in getting just the right gear and speed to do the job while watching the temperature.
The selected media item is not currently available.Barry BEAM #16014
2003 U320 40' AGDS
Beamalarm, Foretravel technical help and specifications
"Whatever the mind can conceive and believe, it can achieve"

Re: Cummins M-11 450 Engine Overheating

Reply #16 –
Barry,

If you don't cure the problem with the spray, etc., it might be a good idea to have the coolant checked for products of combustion. Sometimes a light leak can result in elevated temps and a lot of head scratching. I have cured that problem with a simple retorque of the cylinder heads on a couple of occasions.

If you have not been to Cancun before, I can suggest Eco-hotel Rey del Caribe downtown Cancun for a very pleasant place to stay in old town that is not on the generic hotel strip. PM for photos or other Yucatan tips. Ride up front in the airport bus and check the slick 6 speed manual transmission.

Pierce
Pierce and Gaylie Stewart
'93 U300/36 WTBI
Detroit 6V-92TA Jake
1140 watts on the roof
SBFD (ret)
 

Re: Cummins M-11 450 Engine Overheating

Reply #17 –
The pressure cap increases the boiling point by 3 degrees per pound of pressure..Therefore a 15 pound cap increases the boiling point from 212 degrees to 257 degrees. If your antifreeze is 50 percent water and 50 percent antifreeze, the boiling point is raised another 10 degrees..resulting in a 267 degree boiling point. The engine is harmed when the coolant boils, because once it boils it can no longer pick up heat from the engine and internal damage results.. usually a piston sticking to the cylinder wall....
2001 U320 40ft
Build #5867
2003 Tracker
VE7DOD