On our return trip from Moro Bay this past weekend the drive belts starting squealing. I pulled off and a check didn't indicate they were lose so I sprayed them with WD40. They were quiet for about 30 miles and the temp was normal. Good thing because it was 106*(OUCH!) passing through San Ardo. About that time the clutch fan kicked in full blast. Sounded like a 747 passing through the middle of the coach. Temp was still normal. Just south of King City heard the dreaded sound of a drive belt self destructing and the fan went quiet. Temp went up on the high side and I kept going for we were only 12 miles from home. Between turning on the heater and coasting down hill in neutral I kept the temp within range. After cooling down an inspection showed that when I had the drive belts replaced the moron put the wrong sized water pump and power steering belts on. That was 5,000 miles ago and since then they streached to the point that the water pump was only operating a half the speed it should have been. I have replaced the belts with heavy duty ones. Now I discover the cluch fan is fully engaged and needs replacing. In my younger days I ran 440's on the street an used an eight bladed flex fan. Was wondering if anyone has used one of these fans or is currently using one? If so what kind of performance are you getting from it? Our Clipper is a 78 21' rear bath with a 440. We seldom tow anything, but do install a cargo carrier that I constructed for our three wheeled scooters. When we do tow it is my 67 Ford F100 pickup that weighs out about 5,000 lbs depending on what I load in the bed. Mostly it is fire wood and the two scooters. Thanks an keep on a Clipping!

Roger & Loreen
#3206

Clutch Fan and Belts. Your lucky you got home .    Bob Chaney

Thanks Bob. I'm aware that WD40 is not good for belts, but it was the only thing I had with me at the time. I use an industrial type belt dressing that is used on electric generator drive belts. Those puppies will not slip with this stuff. I have been attempting to find out if anyone has or is currently using a eight bladed flex fan in place of the clutch type. Ha very good luck with them in my muscle car days. Going to give it a try and see what happens. Again thanks for your reply and "keep on a clipping". Roger and Loreen

Roger:  It is my understanding that flex fans move more air at slower rpm and less at high rpm thus reducing fan drag and HP loss at high rpm but always using some engine power.  What RVs need is higher air flow through the radiator when the temp is up independent of the motor (fan) speed.  I don't think a flex fan will help as much in slow moving stop and go traffic as much as an electric fan set up. Has anyone in our Clipper world done an electric fan installation?  If so I'd sure be interested in the details.  If you install a flex fan please give this forum a follow up on how it performs for you or e-mail me your impression to me at mollerus@worldfront.com.
Bob Mollerus

My Clipper came with a flex fan which did not seem to be doing what the a/c system needed.  When I replaced it with a new fan and thermal clutch, the cooling improved and the noise level went way down.  I really think the flex fan is over-rated.  After about a year, the thermal clutch began to act up and Checker replaced it at no charge.  The new one works great and I'm quite happy with it.    

Electric fan(s) will cost more than replacing the clutch fan or going to a flex fan. I ran a flex fan on a big block ford hot rod and it worked great but was noisy all the time. Everything is a trade off. There are electric fan kits for engines up to 400HP. There are photos/details of an installation (not motorhome but the same factors apply) at http://www.thumper300zx.com/modifications/fanconversion/fanconversion.htm. If you do some research you will find the off-road truck people sometimes install two fans, often with two thermostats set just a few degrees apart. With electric fans you can set it to eliminate boil-over after you shut the engine down. I had an electric fan in a landcruiser with a chevy V8 and it worked great. Only came on when needed. Permacool makes excellent quality electric fans, shrouds help even if you have to make one yourself

Roger,
Don't even think about a flex fan.  I have used them on different vehicles over the years with good success but when I tried one on my '79 Clipper with a 440 it was very noisy and it blew air right past the engine cover seal.  I installed a Mopar Performance clutch fan from Summit Racing and it works great.  You might want to think about a high volume water pump and a Mr. Gasket thermostat.  I put all that on mine plus a double roller timing chain, high volume oil pump and a new radiator.  It ran better than new.  I've towed my 19' ski boat loaded with gear in 100 degree heat and it never came close to overheating.  You also might want to make sure your mufflers have good flow, exhaust back pressure can cause overheating too.  Finally, you might see a lot of suggestions here in the forum to install a double pulley on the power steering pump if your belts squeal.  Mine did so I replaced the power steering pump, flushed the system and used the newer Valvoline synthetic fluid.  It has never squealed again.  Good luck.

I had an RV with a Chevy 454 engine and electric fans.  There were two of them.  This worked very well.  I had an adjustible thermostatic switch that would turn on the electric fans.  For a while I had one fan with a manual switch and the other on the thermostat.  I found that one fan was enough for stop and go traffic, but I eventually hooked both up to the thermostatic switch.  The fans never came on while above 35 mph.  This vehicle  did have an air dam and a sealed air scoop before the radiator.  I found the electric fans to be very quiet.  I had a light that came on when the fans were in operation so that I could tell when they were on.  The vehicle was a 27 foot RV that got beween 8 and 9 mpg at 60 mph.  This was a class A and I think better streamlined than a class C.  Also, the electric fans took a lot less power from the engine than a belt drive fan so that would help some with the better mpg.  I was surprised when folks here told me that my American Clipper is going to get poorer mileage than the 27 foot RV I had before.  

Do you have the two belt setup for the water pump?  This resolves the destruction of the power steering [single] belt.  I fought this for over 15 years before adding the second water pump belt.  Hope this helps.

I have been fighting high coolant tempertures 220* on hot days high speeds 50-60 mph and the belt squeeling at 55-60 mph. I've tried every recomendation this forum has to offer in terms of new clutch fans, proper water pump, big mouth thermostat even with extra holes drilled in it and a ported goose neck, new belts, etc. Luckily no over heating or boil over. I've even installed the biggest single electric fan summit racing has to offer. The electric fan has only helped reduce coolent tempertures at idle, nothing at highway speeds. I also have an auto meter coolent gauge and it works well, it doesnt lie. The motor is rebuilt and balanced, all edlebrock high performance package, doug thorley headers large exhaust, fresh radiator, etc. with a dyno reading of 125 hp at the rear wheels. That may not sound like much, but the people who high performance tuned it were impressed being that it is an RV. Its not over advanced at timing. MY next attempt at the high coolent temps will be a different radiator. U.S. radiator out southern CA has a triple flow they swear by, and several sizes that will most likley cover the American clipper applications. As for the squeeling belt issue I have tried belt dressig (many kinds), retighting the pump, new pump, etc. The dressing only works for a while. I will locate a double pulley for the steering pump. My water pump has an extra slot for the second belt. I may try a flex fan to reduce drag on the belts at high speeds. The belt squeel seems to be rearing its ugly head more and more as these riggs get older and it seems every one has found something that works for them, but not every one. I think this will be vey common discussion as time goes on. chris zahnd # 2786

hmmmm.........

A faulty thermostat can cause all kinds of problems. Sometimes fluid is moving through the system TOO FAST - and doesn't get cooled down properly. Maybe go back to a "stock" thermostat, get your radiator checked out again, and your water pump as well to be sure it's not moving too much water.

Also, on occasion, a radiator hose (usually the bottom one) can "collapse" due to pressure at higher speeds, and restrict fluid flow - check your hoses for this phenomena.

I'v read all the letters about over heating and Horst is correct if the water is going through the radiator to fast it can't be cooled, having the radiator rodded out cool motor home water pump better but stick with the stock thermasat it will slow down the water enoff to let it get to all the cooling fins ask someone ho has removed the thermastat and found out the hard way that none of your smog systems work in cooler weather and then the motor boils when it gets hot out why the water is raceing throght the radiator to fast another thing people make a mistake about is trans coolers or better yet how to plum them you want the fluid to go to the aux trans cooler first then to the radiator if not the fluid gets cooled to much my Da had the stock thermatat in his clipper and towed a car to phenix without over heating

What is a stock thermostat?

I have a chevy 400 and just changed my thermostat to 160 degress instead of the 195 I pulled off it.

Should I have done this?

I have used an infared gun to check radiator and motor temps and got reading of over 200 at goose neck, slightly lower at top of radiator, and then sigificant lower readings at the bottom of radiator, so I dont think coolent is running through the radiator too fast.

Chris,
Are you "losing" any fluid?
Doesn't have to be be a visble leak - but are you finding that your resevoir is down after a trip?

Just wondering if you might have a  head gasket issue or (gulp - and hopefully not) a cracked block.

Burning oil?

All your fan shrouds are in place and properly installed?

Could your fan belt be slipping at higher speed, and thus not turning the fan quickly enough.

You might want to try installing an air dam. I've been on the lookout for one in junkyards for a while now - no luck. I don't want to get a JC Whitney one - want to find a 70s Dodge Conversion Van with a nice trick air dam - I understand that they really push air through the radiator while at the same time reducing turbulance for better handling and fuel economy.