Side Mounted Fans

[jleamont]

I wanted to know if I have a problem or if this is normal. Every time we drive into a campground that is not paved after pulling off of the highway, we stir up a tremendous dust cloud which causes the rear of the coach to disappear into a cloud. This get frustrating since I just washed it prior to leaving and it did look nice.

I was trying to figure out if a lower portion of my shroud was missing and the air was dropping down or if this was normal?

My temps run at 185 degrees except when pulling large hills it will climb to just shy of 200 degrees so I do not feel there is a lack of cooling.

Anyone else have this issue?

[wolfe10]

Most side radiator coaches have either two speed fans or variable speed fans.

So, first question is: Is your fan system operating as it should, or it is "stuck on HIGH". Note, high is the normal default speed, so if there is an issue, you will have the fan stuck on high. This leads to not only lots of dust at low speeds, but less HP and less MPG on the road, since you are using the extra power to power the fan on high speed.

Monaco should be able to give you insight into how your system works and how to verify that it is working properly.

With that said, most of the air forced through your CAC and radiator DOES exit the bottom of the coach.

[jleamont]

Hmmm, when I start it up it is not on until the engine warms up, but then it is always on, or should I say I always hear it even at hot idle it's moving a lot of Air. So I would say yes It's stuck on high? Anyway to test? Guess it's time to call Monaco

Thanks

[tbutler]

We get the same cloud of dust that you refer to when in dusty conditions. I know my fan isn't running full always, just when the engine is hot from highway travel. If you watch the temperature (we have the Aladdin monitor) it takes quite a while for the engine temperatures to cool down. Just because you are off the highway doesn't mean that the temperatures and the fan speed should drop immediately.

[jleamont]

Tom, do you hear it while driving down the highway? Once its on I always hear it, It may be normal but I want to double check the system.

I just figured since the air is not forced through the radiator like a front mounted engine, the fan would engage once up to operating temp and maintain a speed close to the engine RPM's, or at least that is what it is doing. The other concern is I have never driven the coach in ambient temps below 55 degrees, so it may be working properly just the conditions we run may not allow it to slow down.

I can see the motor and it looked new from the rear of the coach looking forward on the drivers side.

On hold with Monaco at this time....more to follow.

[dickandlois]

Just a thought regarding the fan speed.

When you first start the engine in the AM or after you have set at a rest stop for a few hours, does the fan speed tend to sound slower with less air movement.

I'm thinking that when the engine is cool that the fan speed should be low until the temperature rises to the point that its speed needs to increase to maintain the proper engine temperature.

The standard or should I say the proper way to control the fan speed is to have 2 temperature sensors located on the radiator - one near the top at the inlet corner and one at the outlet corner. Both can call for a higher or lower fan speed, should one fail then the default fan speed should be high as mentioned by Brett.

That way if one fails there is always a back up, but if one is always reading high the fan speed would always be high. This set up would also facilitate the operation of a variable fan speed system. One corner hot the other reading a lower temperature so the fan speed should be low or at a medium speed.

Rich.

[jleamont]

Spoke to Monaco tech support, very helpful as usual. Since the fan is not roaring on a cold start it is not stuck on high, if it had been, on a cold start the fan would be screaming immediately. It is a Variable speed with a control valve that is hooked into the cooling system, as the temp of the engine rises the valve sends more hydraulic fluid to the fan motor which makes it spin faster. My fan motor is a Sauer Sundstrand.

They feel it is operating as designed and he told me at most just make sure there is no debris blocking air flow through the radiator which will make the fan work harder. I will have to try to look through with a flashlight.

Thank you everyone.

[obedb]

Just a thought. Could you put a spring loaded interrupt switch in line? If temps are OK you could stop the fan for just a little bit while you are moving in a dusty area. Our rear radiator unit makes quite a cloud in an unpaved area but the fan is always on. My concern is not as much cosmetic as it is mixing with oily residue on the radiator. I can still charge up a hill with very little increase in coolant temp and I want to keep it that way.

[jleamont]

ObedB, I thought about that, I guess I will have to be a bit choosier where I park.

Honestly, campgrounds without paved roads are a dust bowl either way, I hate when you’re sitting by a fire and someone rolls through at a high rate of speed in a golf cart or passenger car and stirs up the dust also, it doesn't taste good in your drink either.

[desertdeals69]

I think the dust is stirred up from the tires not the fan. Follow a car and you will see the dust cloud also.

[tbutler]

j,

I can't say that I notice the fan noise while traveling. I'm sure it is there but I can't separate it from the rest of the engine noise. Maybe I just haven't focused on the noises from the engine.

dd69,

The dust cloud is definitely from the fan as you can see the dust only on the radiator side and see it billowing as directed by a fan. Even at very slow speeds when tires hardly raise dust, the dust will billow from the fan induced air movements.

Given the alternate, a rear mounted radiator, I am happy to have the easy access to the engine that a side mounted radiator provides. I regard the dust cloud as a minor irritation. In my experience there really aren't many locations where this is a problem. It seems to be only the dustiest of locations that I notice this.

[jleamont]

Tom, agreed. I do love the ease of the engine access with the side radiator. I am going to see if there is any air blockage from dirt, given the operating temperature, if there is it's not much.

[huffypuff]

Yes, because of my rear mounter fan it's a two man job to change the belt. One man on the bottom after the rock guard cage is removed. The second man has to access through the inside hatch while the first man works the tensioner and hook the belt around the crank and water pump. The second mechanic hooks it over the alternator and air conditioner compressor. I have done them by myself but it's in and out, in and out until you finally get it. I'm going to change the belt at 50,000 miles whether it needs it or not because you don't want to do these on the road.

[jleamont]

Puff, I would have though that was a side mounted radiator on a Monaco of that size. When we were looking I wanted a rear radiator, my thought was to keep it simple, less to go wrong.

[huffypuff]

Yes it is a rear radiator but it's stacked under the intercooler. Seems like a strange setup but it works very well.

[Oldjoe18]

When I purchased mine the owner told me about this issue, not a problem with fan just what happens when your drive on unpaved roads. He was anal, so we got down and he had cardboard made that would fit under the radiator/fan and bungee cords, he showed me how to hook it up, but he cautioned not to leave it on, but it stopped the dust.

He was a perfectionist, I kept it for 4 years and just threw it away, I don't get on many unpaved roads.

[wepcpo]

Just thought, but my dust cloud is caused by my exhaust tip. On dusty roads even at idle it kicks up and then if I hit pedal it really creates a cloud. It did point straight down but now I turned it some just for that reason.

[obedb]

I may try that too if I can get it loose without messing up. Maybe a 90 degree turn to the outside.

[jleamont]

My exhaust has a 90 on it already it points directly back...helps with fuel econony, like a turbine on a jet.

Sorry, thats what the dealer told me when we went to look at it before we purchased it. The only problem is if you walk past to close it will get your leg every time.

[kaypsmith]

I didn't add anything earlier, but since it has been mentioned, my exhaust turns almost straight down and causes dust on a dirt road. Had my buddy at the sheet metal shop make a stainless

slightly curved plate, then mounted about 4 inches below the exhaust to deflect, it helped the dust about 50 percent.

[F233511]

On my motorhome, the side mounted fan controller is also connected to the dash A/C system. When the A/C is on the fan defaults to high. This works great to keep the A/C working at its peak and the engine from overheating. However, when the A/C is on and I drive onto a dusty road or driveway the cloud will rise!

[obedb]

Visited the storage yard today. My exhaust elbow already points to the driver's side. Took a look after the discussion. Shucks!! We enjoy dry camping, but the thought of my radiator and charge air cooler plugging up with dust! The Wupperman campground on Lake San Cristobal has been a favorite for years. One of the most beautiful spots in the USA. Don't tell anybody though.