Radiator Fan

Topic: Radiator Fan (Read 1160 times) previous topic - next topic

Radiator Fan

October 25, 2011, 08:00:38 pm

My coach is 2000 - U320 42ft.

Which way is the fan on the side mount radiator supposed to blow.

Should they pull air from outside towards engine or blow from engine to outside?

- Roger Berke -

Re: Radiator Fan

Reply #1 – October 25, 2011, 08:09:19 pm

Roger,

Side mounted radiators normally pull air from the outside into the engine compartment. That is the way mine works.

Re: Radiator Fan

Reply #2 – October 25, 2011, 08:37:14 pm

Correct, but replace normally with always. The fan(s) suck air in from the side of the coach and exhaust it into the engine compartment.

Brett

Re: Radiator Fan

Reply #3 – October 25, 2011, 08:39:42 pm

I think mine are backwards (blowing to outside). I need to verify.

Since they are hydraulic, can you just switch the hydraulic lines to reverse rotation?

- Roger -

Re: Radiator Fan

Reply #4 – October 25, 2011, 08:44:22 pm

Roger,

I would start by determining if the fan blades are installed backwards. Also, verify with James Tirana the proper direction of rotation of the fans.

Brett

Re: Radiator Fan

Reply #5 – October 25, 2011, 09:50:30 pm

As I recall, correct rotation looking at the fans from the center of the coach is CCW

Re: Radiator Fan

Reply #6 – October 26, 2011, 08:09:42 am

Quote from: Dave Head – October 25, 2011, 09:50:30 pm

As I recall, correct rotation looking at the fans from the center of the coach is CCW

David,

Just so everyone understands, are you talking about viewing the fan from the engine compartment. And if anyone can confirm this for the OP, that would be great. We are 1,800 miles from our coach, or I would check direction of rotation.

Brett

Re: Radiator Fan

Reply #7 – October 26, 2011, 07:49:01 pm

Fans are rotating CCW.

This is what the blades look like.

Looks like it is pushing air to outside to me.

I will verify with James Triana.

- Roger -

Re: Radiator Fan

Reply #8 – October 26, 2011, 08:33:43 pm

Based on the shape of the fan blades, if these rotate CCW, then it is sucking air from the outside through the radiators, etc. and into the engine compartment.

Re: Radiator Fan

Reply #9 – October 26, 2011, 11:46:21 pm

Quote from: Peter & Beth – October 26, 2011, 08:33:43 pm

Based on the shape of the fan blades, if these rotate CCW, then it is sucking air from the outside through the radiators, etc. and into the engine compartment.

X2! If blade is spinning toward the top from position it is in, it is sucking air from the outside through the ratiators into the engine compartment. You can verify using a 8x10 sheet of paper on the outside.

Re: Radiator Fan

Reply #10 – October 27, 2011, 12:11:20 am

With engine running put a thin plastic drop cloth across the outside fins to determine if you are pulling in or blowing out.

Re: Radiator Fan

Reply #11 – October 27, 2011, 07:31:49 am

We are looking at the fan from the back.
It should always be looked at from the front.

Niagarachip.

Re: Radiator Fan

Reply #12 – October 27, 2011, 08:41:53 am

[snip: Based on the shape of the fan blades, if these rotate CCW, then it is sucking air from the outside through the radiators, etc. and into the engine compartment.]
If it helps this thread, I've observed the mechanics at FOT putting a large towel or other fabric over the outside of the radiator grill with the engine running to more quickly warm the cooling fluid. It's held there by suction. The radiator fan definitely pulls air into the engine bay.

Re: Radiator Fan

Reply #13 – October 27, 2011, 08:53:15 am

This is confusing. If we use a clock's rotation as our standard of measure, shouldn't we measure from the front of the fan motor, and not the rear. Like a clock. All respect to our members, but to say the fans turn CCW as seen from the engine compartment is like saying one should turn left, as seen from the next intersection. If we can measure from the back too, a single motor can be turning clockwise and counter-clockwise, which makes the measurement meaningless.

Am I missing something? Is there a mechanical standard that defines the rotation by where it can be best seen?

oldMattB

Re: Radiator Fan

Reply #14 – October 27, 2011, 08:58:37 am

Quote from: oldmattb – October 27, 2011, 08:53:15 am

This is confusing. If we use a clock's rotation as our standard of measure, shouldn't we measure from the front of the fan motor, and not the rear. Like a clock.

The only problem with your logic is that you can not see the fan's rotation from the outside of the coach, thus we can not measure it from the front of the fan motor. But you could always remove the radiator to see it.

And the "mechanical standard" that defines rotation does not hold true in the sense of "Lefty Loosey, Righty Tighty" in mechanics. There are many mechanical applications where that does not apply because of rotation and the effect there of allowing a bolt or nut to loosen. A big example of this would be the left wheels or rims on a one ton Toyota cab chassis used by the RV industry. But this does not hold true to all model years or models of Toyota Pickups. This is one reason why the industry has maintenance manuals for vehicles. So we know which way to turn the nut or bolt to tighten or loosen it. I once watched a guy spend 30 minutes trying to remove a lug nut from a front left tire on a Toyota. Finally told him to reverse his air wrench and it came right off. He could not believe that Toyota did such a "Stupid Thing", but was it. Looking at the front left tire when vehicle is moving forward, it turns counter clock wise, while the front right tire turns clockwise. If both lugs were to go on clockwise, there is the possiblilty of one side to come loose because of rotation.

To quote one source: "By common convention, right-handedness is the default handedness for screw threads. Therefore, most threaded parts and fasteners have right-handed threads. Left-handed thread applications include:
Where the rotation of a shaft would cause a conventional right-handed nut to loosen rather than to tighten due to fretting induced precession. Examples include:
The left hand pedal on a bicycle.[3]
The left-hand grinding wheel on a bench grinder.
The lug nuts on the left side of some automobiles.
The securing nut on some circular saw blades - the large torque at startup should tend to tighten the nut."

Re: Radiator Fan

Reply #15 – October 27, 2011, 09:34:33 am

I will check air flow later.

Photo below should clarify rotation.

- Roger -

Re: Radiator Fan

Reply #16 – October 27, 2011, 09:54:48 am

Quote from: PatC – October 27, 2011, 08:58:37 am

Quote from: oldmattb – October 27, 2011, 08:53:15 am
This is confusing. If we use a clock's rotation as our standard of measure, shouldn't we measure from the front of the fan motor, and not the rear. Like a clock.
The only problem with your logic is that you can not see the fan's rotation from the outside of the coach, thus we can not measure it from the front of the fan motor. But you could always remove the radiator to see it.

And the "mechanical standard" that defines rotation does not hold true in the sense of "Lefty Loosey, Righty Tighty" in mechanics. There are many mechanical applications where that does not apply because of rotation and the effect there of allowing a bolt or nut to loosen. A big example of this would be the left wheels or rims on a one ton Toyota cab chassis used by the RV industry. But this does not hold true to all model years or models of Toyota Pickups. This is one reason why the industry has maintenance manuals for vehicles. So we know which way to turn the nut or bolt to tighten or loosen it. I once watched a guy spend 30 minutes trying to remove a lug nut from a front left tire on a Toyota. Finally told him to reverse his air wrench and it came right off. He could not believe that Toyota did such a "Stupid Thing", but was it. Looking at the front left tire when vehicle is moving forward, it turns counter clock wise, while the front right tire turns clockwise. If both lugs were to go on clockwise, there is the possiblilty of one side to come loose because of rotation.

To quote one source: "By common convention, right-handedness is the default handedness for screw threads. Therefore, most threaded parts and fasteners have right-handed threads. Left-handed thread applications include:
Where the rotation of a shaft would cause a conventional right-handed nut to loosen rather than to tighten due to fretting induced precession. Examples include:
The left hand pedal on a bicycle.[3]
The left-hand grinding wheel on a bench grinder.
The lug nuts on the left side of some automobiles.
The securing nut on some circular saw blades - the large torque at startup should tend to tighten the nut."

I was really asking if there is a standard for measurement of rotation direction, not a standard of direction. I suspect the standard measure must be independent of the conditions when it is installed. If we consider the fan to be CCW because the radiator is in the way (when it turns from right and over to the left from our perspective), the shop that sells a new fan or fan motor would not know if the view would be obstructed, and would likely sell us the opposite of what we need (generally speaking). If we look from the back and the fan appears to turn CCW, we would know that it would be CW from the front, just as if we were viewing a clock. This would not apply to threads, because there is always an objective measure - from whatever angle of view, the threads do not change direction. We always consider the direction of threads as if we were viewing from the front. I suspect it should be the same for a fan motor or blade.

Having said that, I had a fun experience with a Ford Aerostar fan clutch, which threaded on. The instructions that came with the clutch AND the Clymer's manual were wrong in regards to the way to turn for removal! My buddy the mechanic and I spent hours trying to loosen, and eventually attempted to saw it off. After driving us to exhaustion, I tell no lie, we stood staring at it, and watched it as it loosened about 1/8 turn on its own!

oldMattB

Re: Radiator Fan

Reply #17 – October 27, 2011, 10:04:26 am

As has been suggested by several, invest in a sheet of newspaper and 2 minutes of your time.

Hold the newspaper across the CAC/radiator grill-- if no "helper", just use a couple of pieces of tape.

Start the engine. See if the newspaper is sucked into the grill as it should, or if it blows away from the side of the coach (in which case you need to go to "Plan B").

Plan B could be as easy as turning the fan around, or reversing the hydraulics. IF he posts that air flow is the wrong way, perhaps someone with the same coach can post a photo of their fan-- that will tell him if the fan is installed properly or reversed.

Brett

Re: Radiator Fan

Reply #18 – October 27, 2011, 05:40:02 pm

I have the same year but U295 and mine is the same ccw sucking in from the grille and as others have said before me that is what the fan is showing by the crap that is on the one side of blade.

Re: Radiator Fan

Reply #19 – October 30, 2011, 08:49:06 pm

Checked the air flow with light plastic. Much to my surprise the air is being drawn in towards the engine.

Thanks for all the help and responses.

- Roger -

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