Big Radiator Fan

[Ron & Dee]

For the past couple of years my big fan seems to come on sooner than it did when we first bought the Motor Home.

The Motor Home was 2 years old when we purchased it and have had it for 3 years. The big fan didn't come on unless the outside temp was in the 90's or we were climbing some steep mountains. Last year the fan started comming on around the 80's and now this year it is starting to come on in the 70's and when we are slowing down.

The engine doesn't seem to be over heating but the temperature gage doesn't seem as constant or steady as it used to. There is a slight rise in the temperature indicator needle, then the big fan comes on and the temperature drops way back and the fans shuts off.

The air dam is quite deteriorated and does need replacing. Last Summer while on vacation the air dam was only covering about 50% of the space above the radiator. While having some service work done in Roanoke Virginia the mechanic repaired the air dam as best he could.

I don't think I have any over heating problems, but my main concern is why the big fan is comming on sooner?

Thanks,

Ron

[Ron & Dee]

For the past couple of years my big fan seems to come on sooner than it did when we first bought the Motor Home.

The Motor Home was 2 years old when we purchased it and have had it for 3 years. The big fan didn't come on unless the outside temp was in the 90's or we were climbing some steep mountains. Last year the fan started comming on around the 80's and now this year it is starting to come on in the 70's and when we are slowing down.

The engine doesn't seem to be over heating but the temperature gage doesn't seem as constant or steady as it used to. There is a slight rise in the temperature indicator needle, then the big fan comes on and the temperature drops way back and the fans shuts off.

The air dam is quite deteriorated and does need replacing. Last Summer while on vacation the air dam was only covering about 50% of the space above the radiator. While having some service work done in Roanoke Virginia the mechanic repaired the air dam as best he could.

I don't think I have any over heating problems, but my main concern is why the big fan is comming on sooner?

Thanks,

Ron

[Mahlon]

The fan clutch may indeed shift to "high" when you slow down (or at least ease off on the accelerator pedal) because engine RPMs decrease, which means less airflow through the radiator, which means the coolant gets hotter, so the fan clutch engages to compensate. The fan clutch thermostat (mounted on the front of the clutch) is purely mechanical, so all it knows is the temperature of the air leaving the radiator.

I doubt that there's anything wrong because the usual failure mode of these clutches causes them to stay engaged no matter what the air temperature is.

Do repair/replace the air dam, that can only help.

[Ron & Dee]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">
Do repair/replace the air dam, that can only help. </div></BLOCKQUOTE>

Thanks Mahlon,

I'll probably do that and also blow some bugs out of the A/C condenser and radiator.

Ron

[Ron & Dee]

Follow up report on my Big Fan operation.

I am now a happy camper since I replaced the air dam as suggested by those in the know.

As I stated above, my air dam had become quite deteriorated in the past couple of years so I had it replaced a couple of weeks ago. This weekend was the first trip that we have taken since replacing the air dam and I must say, the fan doesn't come on as often and when it does come on it doesn't stay on as long as it did before.

Ron

[DriVer]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Ron & Dee:
I am now a happy camper since I replaced the air dam as suggested by those in the know. </div></BLOCKQUOTE>Ron, I speak often about replacing and or making sure that the air dam is in place while blocking as much of the space above the radiator as possible.

You have proven the result of assuring that the air dam is installed and properly fitted.