I am reaching out to all you RV Veterans because my RV keeps overheating. I have a 2008 Fleetwood Discovery 39R with only 20k miles. The RV is currently at Freighliner. This is the second time since November it has been there. First they replaced the Engine Harness and the Temp Sensor, this took two weeks to complete. On this visit they have replaced the Thermostat. Monday will be another two weeks they have had it. After speaking with their foreman today, they say it does fine on flat surface but overheats on any grade. Any ideas? I'm at the end of my rope and checkbook?

What type of fan system is on your rig?Is it on the engine, hydraulically operated or electrically driven? Could be it is rotating in the wrong direction.

interesting that they would change out the engine harness first, Did they have data from the control module that it was a load problem or a heat rejection problem or a bad instrument reading. If your gas milage is typical/normal I think Moses lake has pretty good input. Does transmission temperature track that of the engine. If so then instrument bad may be ruled out.

Should we assume there is slobber tube installed? After asking that, my 2005 Fleetwood Excursion (same thing as the Discovery) has a Cat C7 and needs the slobber tube. You may have the Cummins which I don't know if it needs one?Besides that issue, have they cleaned the radiator and CAC?Bill

It doesn't seem old enough to be suffering from core fin separation but it may depend on the environment it has lived in. If the fins lose their bond to the tubes in the radiator core they will not transfer enough heat out into the fins/air. I have seen it a few times but it's usually on older equipment. Usually starts at the lower sides. The fins will easily pull right off the tubes. Real bad ones will just flak apart. The complaint was the same as they described. When did this start was it gradual or more sudden?

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azrving
Explorer
Jan 15, 2015
It doesn't seem old enough to be suffering from core fin separation but it may depend on the environment it has lived in. If the fins lose their bond to the tubes in the radiator core they will not transfer enough heat out into the fins/air. I have seen it a few times but it's usually on older equipment. Usually starts at the lower sides. The fins will easily pull right off the tubes. Real bad ones will just flak apart. The complaint was the same as they described.

When did this start was it gradual or more sudden?
Trackrig
Explorer II
Jan 15, 2015
Should we assume there is slobber tube installed? After asking that, my 2005 Fleetwood Excursion (same thing as the Discovery) has a Cat C7 and needs the slobber tube. You may have the Cummins which I don't know if it needs one?

Besides that issue, have they cleaned the radiator and CAC?

Bill
traveylin
Explorer
Jan 15, 2015
interesting that they would change out the engine harness first, Did they have data from the control module that it was a load problem or a heat rejection problem or a bad instrument reading. If your gas milage is typical/normal I think Moses lake has pretty good input. Does transmission temperature track that of the engine. If so then instrument bad may be ruled out.
w4phj
Explorer
Jan 15, 2015
Dirty CAC?
enblethen
Nomad
Jan 14, 2015
What type of fan system is on your rig?
Is it on the engine, hydraulically operated or electrically driven? Could be it is rotating in the wrong direction.

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