Question? Clutch Fan On More. Two different MH's

[FreshAir]

My friend has an 04 Dolphin, 35', I have an 05 Pace Arrow, 36'. His clutched fan runs a lot more than mine while traveling together. Why would that be? Weights are pretty much the same and he is probably lighter.

[FreshAir]

My friend has an 04 Dolphin, 35', I have an 05 Pace Arrow, 36'. His clutched fan runs a lot more than mine while traveling together. Why would that be? Weights are pretty much the same and he is probably lighter.

[Joe Gilbert]

I expect it has everything to do with how much ram-air is able to flow through the grill opening and through the raditors. Actually I thought the Dolphins moved more air through than other makes as noted by the lack of burnt sparkplug wires on National products. If you could actually check the temp cut-in on the clutched fans I'll bet they are both in spec.

[DriVer]

Please inspect both of your fabrics which are attached from the top of the radiator framing and the upper coach body. It could be altogether likely that the fabric that covers the most holes over the top of the radiator will exhibit a tendency of running less.

Covering the most amount of openings allows more air to flow through the cool pack. This will reduce the amount of time that the auxiliary fans need to spool up and spin.

[FreshAir]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by DriVer:


Covering the most amount of openings allows more air to flow through the cool pack. This will reduce the amount of time that the auxiliary fans need to spool up and spin. </div></BLOCKQUOTE>

We were thinking about the grill size and the frabic air dam covering but they both are in good shape and grill openings are about the same.

The only real difference, his, the Dolphin has full fabric coverings on the sides of the engine where mine has none? It looks like the enclosed engine would not pass the hot air out as well as the open ones. He has considered removing the side coverings but is hesitant to do so.
Any thought's on this?

[M&EM]

I've considered removing the side fabric coverings on mine after seeing many OBs without them.

Bottom line is: Haven't recalled any Dolphin burned spark plug wire issues reported here.
So I am leaving it the way it is . With 46k miles and no heat issues, it must be ok.

Marty

[DriVer]

I am suggesting that you plug up as many avenues for air to flow around the cool pack (radiator) as possible and attempt to channel as much air through the cool pack as possible.

The coach builder's grill work looks really nice sometimes however the flow-through properties of the grill may not be as open in design as some others.

An air dam or spoiler directly under the nose also helps pull heat from the engine. It's a ground effect and it can create a vacuum to some extent and cause a slightly lower pressure area under the engine thereby drawing down heat.

If you ever get a chance to see a UFO radiator shroud, you will see that 100% of the air that is directed by the main cooling fan is passed through the cool pack - but in reverse. The air flow comes from around and under the engine and is pushed through the cool pack and out the rear of the motorhome. Any heat picked up in the jet-stream while it travels over the engine isn't enough to cool the engine to any appreciable degree. This is why I am suggesting that air must be channeled as much as possible through the cool pack. "IF" a (DIY) device in the shape of a trapezoidal shroud could be fitted to the front of a cool pack in front engine applications, I bet you could capture 95% or more of the air coming through the grill and direct it toward the cool pack.

This is why the UFO cools its engine more than adequately in any climate.