Radiator fan alternative?

[DigitalFrostbyte]

Sent: 2/19/2008 9:08 AM

So the original problem with my radiator is that the motor mounts that are bad, in combo with a bad water pump (replaced water pump) caused the fan to hit the radiator and damage about 5 cores.

I do not even have the money to think about replacing or recoring.... so, I was thinking of closing off those cores then taking a subaru/honda/toyota electric large radiator fan and bolting it to the radiator and doing a switch on the dash for going uphill and traffic.....
this has a temp guage, what temp is normal for the 318 to run at, what is hot, what is too hot?


Am I being silly? lol thanks...

[denisondc]

Sent: 2/19/2008 6:36 PM

Slantsixness would know the best answer. Mine would sit in the middle of the gauge, the pointer straight up - when I had a 180°f thermostat in it. It pointed to the lower 3rd of the middle region of the gauge with the 160°f thermostat, and to the right hand 3rd of the middle region of the gauge with the 195°f thermostat in it. The hottest it would get on long upgrades was still within the central region, i.e. not to the right of the central marked segment. I did see it hotter than that one year, because our radiator was partly clogged, and the system was boiling coolant out.
The gauges arent very consistent from one RV to another, but they are at least consistent with how they read in one vehicle; so whatever your gauge shows you when running on the level is what you could consider normal. I would begin to worry if the gauge got to the extreme end of the markings at the right side of the gauge. Beyond that I would call it 'too hot'. Going down a long slope it will probably read much lower than normal.

My opinion of mopar gauges is the reason I added a mechanical water temp gauge and an oil pressure gauge before we ever took ours out of the driveway. In the years we have had it, I have replaced the oil pressure sender once, and the water temp sender twice. In none of these cases did the oil pressure or water temperature misbehave, even though the gauges indicated -disaster-.

[ZR91]

Sent: 2/19/2008 8:58 PM

If your rad is not too badly damaged, you could remove it and silver solder the damaged sections. Regardless, an electric fan is more efficient, and if installed correctly in conjunction with a thermostatic controller ( Hayden or equivalent) you can have improved cooling and save fuel at the same time.-There is after all a reason that most light truck manufactures are switching to electric fans, and it is not to lower production costs.

We used an electric fan setup from a Ford Taurus and a 180 T-stat, and our 440 never gets past 1/2 on the factory guage(190 on the aux temp guage)

That being said, you should probably also repair your motor mounts asap.

Jay

[ClydesdaleKevin]

Sent: 2/20/2008 6:27 AM

I would guess that if properly set up an electric fan would work at least as well as the factory mechanical fan, but I would still be concerned about your transmission getting cool enough.  The transmission is cooled by a little mini-radiator sitting inside the bottom of your stock radiator.  A mechanical fan blows air through your whole radiator, including the bottom section, which is crucial for keeping your transmission cool.  I think that to be safe you would have to have a huge electric fan, or at least more than one to blow across as much of the radiator as possible.

Have you tried junkyards?  You might be able to get a radiator on the real-cheap that is still in good shape.  Or you might be able to retrofit a radiator from an older Dodge van with a 318 motor...our old 85 Dodge van had a 318, and when I bought a brand new radiator for it, with the transmission cooler in the bottom tank of the radiator, it was only 100 bucks...and that was only a couple of years ago.

Whatever you decide to do make sure you fix those motor mounts so you don't run into the same damage again.

Kev

[Lefty]

Sent: 2/20/2008 5:51 PM

Closing the damaged cores off will work, withthe understanding that the cooling ability of the radiator will be reduced slightly. I have taken snips and cut damaged cores out before (soldering the ends), and I live in a hot climate.
As for an electric fan, I would get one off the largest vehicle I could find that would fit. You can even install factory style temp sensors that would cycle the fan on & off as needed. Usually, there is one in the radiator, and another in the intake. thre are aftermarket kits that mount the sensor externally on the radiator core as well.

A 318 with a standard 180deg. thermostat should run at around 190-210deg. depending on your climate. Keep in mind that a 50/50 mix of antifreeze and water at 7psi won't boil until around 235deg. or so.

[toddabney]

Sent: 2/21/2008 8:29 PM

hey jay, i just got a 73 brave w/440 last summer. i took off the stock fan and installed a 12 volt fan i got off the internet and from napa the thremo stwitch for the fan.not sure on the thermastat temp. thanks for backin me up!!i was worried that i had screwed up buy changing fans..i even bought a extra one and the those special zip ties to install them.i thought of putting one on the front of the raditior as well. i don't think i can OD on the cooling.there is a "pull a part "near me and i thought a nice mercedes fan( 15 bucks)( would keep things in check.          the added bonus of having the electric fans is that after i shut the rig down the fan runs for awhile. i had plans of installing a timed fan down there.i was shocked as to how hot it gets in the "dog house".i couldn't imange how  hot it gets in the summer!! so back to the bonus, it feels good to know that the fan is moving the air around for a "cooling off time". but then i worry"what if the wind cracks the heads?"i hope not............happy trails,todd

[ClydesdaleKevin]

Sent: 2/22/2008 6:36 AM

LOL Todd!  Running the fan after engine shut-off won't hurt anything.  But you should make sure that you let the engine idle for a few minutes before you shut it down so the cooled water can circulate into the motor and cool it down too.

Kev

[13503gds]

Sent: 6/14/2008 8:39 PM

Boy to think that an electric fan can NOT replace the HP hogging inefficient flex fan is an urban myth. I just purchased a used fan from a Lincoln town car . This thing draws about 4000cfm. Hook it up to a temp sensor soldered into the top tank & it's way better protection than the old clutch fan. It's ability to cool at idle in traffic is understandable. Works on rpm only. Not the electric fan, you can get a staged controller or simple on/off with a temp sensor. The one I mention covers the entire rad as the original shroud.

[cupcake]

Sent: 6/15/2008 10:39 AM

Some questions in regards to your electric fan? Iam guessing that you removed your stock fan & electric fan mounts on engine side of radiator, drawing air thru radiator blowing it back over engine same as stock fan? Is entire radiator surface covered by shroud and fan? I have considered the electric fan myself, just wondering what anybody else has tried. 
Thanks

[13503gds]

Sent: 6/15/2008 5:39 PM

The "stock fan" was an old clutch fan. I am in the process of replacing the engine with a 94 dodge 318 magnum mulitpoint fuel injected engine. Yes I did remove the clutch fan on this engine. I have the replacement as mentioned above. In 34 years a whole lot has changed since Winnebago built my 74. Most of it positive. If you look what's being built in the auto industry belt driven fans are becoming scarce for a reason.

[denisondc]

Sent: 6/15/2008 6:56 PM

I know belt driven fans are rare in the auto industry - because there is no easy way to spin one if the engine is transverse with the serpentine belt on the side. They still are used with some of the longitudnal engines though, in pickups and SUVs for instance.

An electric fan (a big one) would surely work well in most cases, i.e. terrain with only rolling hills: But I wonder how well they would cool an engine that was running at full throttle, going less than 30 mph in 1st gear - up a long grade in the mountains for instance; especially if you are towing a car or other load behind you.

Dont most heavy trucks still use belt driven fans? ...with an electric clutch to uncouple the fan from the hub when its not needed.

[toddabney]

Sent: 6/15/2008 8:12 PM

i ,ll say amen on that. i replaced my fan with the clutch affair with a electric fan i got online. but i have a "pull a part" junk yard  just down the road and fans there are $10 bucks i think. i'm heading down looking for that lincoin fan.thanks for the tip. i think i will buy a spare of some kind,just in case or even double them up......take care todd

[ZR91]

Sent: 6/17/2008 10:47 PM

Well,

I am very pleased with the electric I installed on our motorhome. The 440 runs cooler than ever in traffic, and the fan rarely even turns on while driving at highway speeds, unless we are climbing a steep grade

Jay.

[olhillbilly31]

Sent: 6/23/2008 10:30 PM

Are our motor homes with the 440's supposed to have fan shrouds...? if they do, i got to get one of those to....i think i will take you all advice and get a electric fan while im at it....

[denisondc]

Sent: 6/24/2008 6:19 AM

Yes, there would have been a fan shroud originally. It might have been made of plastic in later years.
I have never seen a CFM rating for the belt driven fans on our motorhome engines - . My Winnie came with its original viscous drive fan clutch, which at low rpm spins the fan close to the rpm of the water pump pulley (which on mine is about 50% faster than engine rpm), and allows more slip at higher engine speeds. I think the fan's top speed was typically about 2500 with the RV motionless - regardless of how much faster the engine was turning. This design seems to be fully adequate, even when towing uphills in 1st gear in hot weather.
The amount of air going through the radiator will always be some combination of the amount the fan moves and the speed of the vehicle through the air. CFM combined with "airspeed".

On level terrain at any speed above 35 mph I imagine the fan, -any fan-, is un-needed, since the incoming 'ram air' would be enough. Unless you have a ferocious tailwind of course - but then your mpg would be 'great'.

The best type of fan is the one the owner is happy with. I replaced my original viscous drive fan clutch with one combining the viscous drive and a thermostatic element.

I have seen late model heavy trucks that have a belt driven fan, but with an electric clutch to make the connection. When that clutch kicks in, its entirely obvious, from inside the cab or when driving along-side the things.

[13503gds]

Sent: 6/29/2008 6:44 PM

The fan off the Lincoln town car pulls really good, tested with a cfm meter almost 400cfm.   My new magnum 5.2 in the winnie is going to look & run cool.

[jbmhotmail]

Sent: 6/30/2008 10:33 PM

I saw a "pull type" electric fan at:

http://www.surpluscenter.com/item.asp?item=16-1362

870 cfm, 12 vdc, 7.5 amps max, 12" blade diameter, size: 13-1/4" X 2-1/16, item 16-1362, $34.95 each + shipping.

I have purchased items from this company and would highly recommend them.


Admin edit:  As of 3/17/2013 this item has been discontinued.   

[Mosin]

Sent: 7/17/2008 6:15 PM

Driving Pandora through Red Bluff, CA on Hwy 5 @ 115 degrees outdoor temp 10 days ago (height of the recent heatwave) I found that I could only go 53-54 mph and still stay at 210 deg on my mechanical gauge. 60 mph and it would climb up towards 220. Later on that day, in more like 95 deg temps, I was pushing 220 deg on hills, which stresses me out. IMHO the new engine ran amazingly well and cool relative to these extreme temps (of course, with correct skirted thermostat and 110% tuned up with fresh 20/50) and I certainly could have pulled over and just waited out the heat. As it was, I didn't lose any oil or coolant the entire drive. The thing is, I don't want to have to pull over, nor do I want to have to slow down. Soooo...

My current plan is to install the largest, highest CFM pucher electric fan I can find on the front side of the radiator (which, btw/ is already has an extra pass) while leaving my stock fan in place. The idea is to enable me to manually switch on the electric fan in traffic or on steep grades to supplement the stock fan. I am fairly confident it will achieve these objectives (please someone correct me if I'm wrong) but I'm not sure if it will be supplemental/helpful, moot, or even a drawback on flat ground at highway speeds such as my situation in Red Bluff. (??) I have rejected the idea of two alternators to compensate due to HP dwaw, but plan to install the largest single alternator that will fit to boost the amps.

Thoughts? Advise? Additional considerations I am missing?

Thanks!

Dave

[ibdilbert01]

Sent: 7/17/2008 8:28 PM

If your going up a grade in hot weather at roughly 50+mph, adding a fan could make things worse. I don't think any electric or mechanical fan will increase the CFMs you already have by traveling at or above the speed of 50mph. Adding the fan might actually decrease your airflow because now it will be working against the fan. It might however help in traffic. This is just my thoughts, hopefully we will have some other gear-heads answer and give us their thoughts.

BTW, Other than the spinning of the extra mass and other minor drag created, the amount of HP you loose with adding a second alternator is directly related to how much energy you are producing. Here is the formula that I use.

Amps x Volts = Watts
Watts / 745.7 (one HP) = Electrical HP Produced by the Alternator
HP x 15% Efficiency Loss = HP Loss
HP + HP Loss = Total HP Used

To keep it simple, for every 1000 watts, you only need about 1.5hp.

[Mosin]

Sent: 7/18/2008 2:28 AM

Thanks for the tip/formula re. watts. Being a complete electronic/s newby and a historian (which inherently makes me mathematically challenged , how much HP would be drawn by one of these 17 in Derale fans at high speed (23.5A)?. If I can fit them I would consider doubling up as the diagram shows, so I assume multiply that total by two. 

http://static.summitracing.com/global/images/instructions/der-16217.pdf

The next question/issue (I thhink) would be, how big a single alternator would I need to dedicate 47 amps to the fans (if I can fit doubles) and keep everything else going--if that is even possible? Sorry to be so clueless here!

btw/ I do have the stock a/c compressor mount (which I removed along with every last vestige of the decrepit console a/c system) so dual alts is still an option. I'd just prefer to go with a whopper single and keep my relatively new current one on hand as an emergency spare.

Thanks again!

Dave