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Topic: Engine running cold 175 degrees  (Read 371 times) previous topic - next topic

Engine running cold 175 degrees

I just had the radiator flushed at Foretravel. On the way back to Arizona I noticed when traveling at highway speed temperature gauge was showing 175 degrees.  When I slowed in traffic temperature rose to normal about 185/190, but when I increased to highway speed it drops to 175.
When I got home and after engine cooled I ran engine at high idle.  The fan started to kick in intermittently at 150 and started to run on high at about 160. Took it out for a test drive and got engine up to normal range, butt after a few minutes at highway speed it drops to 175.  Any thoughts?
Bruceolson49

Re: Engine running cold 175 degrees

Reply #1 –
Depending on which type fan controller you have it could have failed. If electronic it may not have got the wires hooked back up properly. If it is the hydraulic wax bulb style the bulb could have failed which can cause the fans to run wide open on start up. More info on what coach you have will help also with troubleshooting.

Mike
Pamela & Mike 97 U 320

"It's not what happens to you, but how you react to it that matters."

Re: Engine running cold 175 degrees

Reply #2 –
NO, a fan on high will not make the engine run cool.

The thermostat is what decides to send small or large flow to the radiator. Small flow and huge air flow will still not make the coolant temperature below thermostatic control.

Replace the engine coolant thermostat.
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: Engine running cold 175 degrees

Reply #3 –
Brett,

Yes you are correct that the thermostat should hold the temp before opening. I should have give that a little more thought. The thing is if the fans are kicking on at the temps he has stated that is controlled by the hyd. controller. So it could be 2 problems thermostat and fan controller.

Mike
Pamela & Mike 97 U 320

"It's not what happens to you, but how you react to it that matters."

Re: Engine running cold 175 degrees

Reply #4 –
Our coach ran in the 178 range. 
Joe & Dottie Allen
Sold!  December 2023.      2000 U320; build # 5645
Our coach " Maxine"
Motorcade #  15922;  Escapee 150950; FMCA F330833; Boondockers Welcome;  Harvest Hosts;  Thousand Trails
'98 U320 from 2000-'06
USAF '62-'66

"Do not spoil what you have by desiring what you have not; remember that what you now have was once among the things you only hoped for." ―Epicurus

Re: Engine running cold 175 degrees

Reply #5 –
Quote from: Pamela & Mike –
The thing is if the fans are kicking on at the temps he has stated that is controlled by the hyd. controller. So it could be 2 problems thermostat and fan controller.
Mike

Agree, may be two separate issues.  Certainly the fan on high when not needed reduces HP and MPG and increases noise.
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: Engine running cold 175 degrees

Reply #6 –
Could be that the gauge is off too
1991 U300 Side Aisle 6V92 Silver #3897
2004 U320 40' #6246

Re: Engine running cold 175 degrees

Reply #7 –
Quote from: BRUCEOLSON49 –
I just had the radiator flushed at Foretravel. On the way back to Arizona I noticed when traveling at highway speed temperature gauge was showing 175 degrees.  When I slowed in traffic temperature rose to normal about 185/190, but when I increased to highway speed it drops to 175.
When I got home and after engine cooled I ran engine at high idle.  The fan started to kick in intermittently at 150 and started to run on high at about 160. Took it out for a test drive and got engine up to normal range, butt after a few minutes at highway speed it drops to 175.  Any thoughts?
Bruceolson49
Bruce please state what year model coach you have. It's not in your profile either. Guessing you have a 2001 or newer coach. Prior years are much different in several major ways. Im Guessing you have a failing electronic controller.
In my particular coach I can override the control and super cool similar to how yours is operating down to about 175 degrees but again I'm can only guess.
Need more information.
 Hydraulic fan controller DIY