another reason to use an electric fan is that if you plan on doing deep water crossings an electric fan can be switched off prior to diving in
Definitely a big plus.
I run an electric fan and am a big proponent of them. If you're worried about reliability, keep in mind most cars on the road run electric fans including the Toyota Corolla and Ford Focus, the two most popular automobiles in the world today. I've been running a junkyard fan in my Crawler since 2004 and it has yet to let me down. In my experience, if you are going to do this then the only way to go is with a variable fan speed controller and I would not be running an e-fan is this was not available.
Allow me to explain. Typical setups run an ON-OFF adjustable thermostat that turns the fan on or off based on the temperature of your radiator (or upper radiator hose). The problem with this is that high performance fans, like Flex-a-lite's 15" Black Magic, pull around 14 amps continuous and probably closer to 20 amps during start or spin-up. Twenty amps is a huge sudden load on your electrical system, and what you'll experience is the following:
- Thermostat reads high temps and turns the fan on at full power
- This causes an electrical "shock" causing your engine idle to surge as your alternator takes on a sizable load
- Fan speeds up to 2,000+ RPM generating a lot of noise
- Fan runs at maximum speed drawing a ton of air through your radiator which quickly drops the engine's temperature
- Temp drops and the thermostat switches the fan off
- Its quiet and your charging system has stabilized
- Then suddenly the fan kicks back on at full power, surging power through your charging system, putting a load on the engine, et cetera...
- Repeat forever during your time idling and Crawling very slow over some rocks
Our cooling system is under increased duress with Rock Crawling for many reasons. Examples:
- Crawling slowly results in minimal air flow through our radiator
- Extra load of hauling our camping gear around
- Extra load of large, heavier than stock tires
- Running these large tires at nearly flat tire pressures
- If you don't live on a plain then you're engine will be working extra hard at combating gravity up every steep hill climb
For these reasons you'll see this fan cycle repeating incessantly: Quiet, peaceful Crawling interrupted with the sound of a F5 tornado.
To solve all this I refer you to
http://www.dccontrol.com/constant_temperature_controllers.htm This is a company called DC Control that LCOwner turned me onto back in 2004. What this controller does is slowly increase the amperage to the fan in relation to the temperature of the engine. So the temperature of the engine isn't rising/dropping/rising/dropping; Instead it holds the temperature nearly constant saving your thermostat from heart attacks as well. You'll have all the benefits of running an electric fan but without any of the negative side affects mentioned above. Also, since the fan is not being accelerated at max amperage, the fan's motor runs cooler and will last much longer (read
very reliable). I am sure there are other controllers on the market but I have not needed to look as my DC Control unit has been working great for nearly 10 years straight. The controller is about the size of my iPhone, is waterproof, and is easy to install just about anywhere.
Another great feature is that the DC Control unit has an under-drive circuit where you can install a switch that will run the fan at 10% power (intended for race cars with under-drive waterpump pulleys). I use this circuit exclusively for Rock Crawling so that there is at least some airflow at all times under my hood when I am barely Crawling along. Moreover, when I park my truck to get out and help spot others, I'll leave the fan running at 10% power, which is about a 1 amp draw (1/4 the draw of just 1 headlight). This way components under the hood don't heat-soak when my truck is just sitting out in the sun not moving. Gives me peace of mind.
I also installed DC Control's variable LED light that slowly changes color from green-yellow-orange-red depending on the amount of current flowing to the fan. The feedback from this is great.
I am quite crazy over this subject and invite you to a few "enthusiastic" electric fan reviews I've posted in the past, mostly regarding the improvement you'll receive in gas mileage:
http://board.marlincrawler.com/index.php?topic=22108.msg234082#msg234082 and
http://board.marlincrawler.com/index.php?topic=22660.msg243208#msg243208Regards,
BigMike
