Hello All,

I am building an MK4 with a Gen 2 Coyote. Like several on this forum with Gen 2 Coyotes, I installed the Maradyne MFA136 fan controller so the radiator fan would not run full speed all the time - see GTBradley's excellent post, https://thefactoryfiveforum.com/show...ny-engine)-115

Installation was very straightforward (thank you GTBradley) and it worked well the first few times I ran the engine, starting the fan at half speed when needed and going to full speed when necessary. Unfortunately, when I ran the engine for the fourth time, there was a popping sound and smoke started to stream out of the Maradyne potentiometer (the part that allows you to set the temperature for fan engagement). Getting a replacement fan controller has been a real challenge. Initially, neither Maradyne or the store I purchased it from were willing to warranty the part. The store said it was Maradyne's responsibility, and when they contacted Maradyne, they were told that there was no warranty once the part was installed (what???). After several conversations between the store and Maradyne, Maradyne supposedly agreed to warranty the part, but they have yet to do anything and it has been a couple of weeks of unanswered phone calls.

Needing to move along with my build, I looked at other options and found that the Maradyne fan controller is probably a rebranded unit as several other companies have identical appearing/functioning units, but with different branding (Summit, Jegs). However, I did find a different fan controller called the AutoCool that I think is a better controller.

The AutoCool unit is very similar to the Maradyne in that it controls the fan by pulse width modulation via the fan ground circuit. The wiring of the AutoCool is basically the same as the Maradyne, except the 1/8" NPT sensor has two wires and there is no ground needed for the sensor housing (like the Maradyne). The AutoCool is very robust, with a nice aluminum case and thick aluminum mounting plate. It has a heavy duty dial on the front to adjust the fan engagement temperature. Probably the best feature of the AutoCool is that instead of just two speeds (Maradyne runs at 60% and 100%), it has several different speeds that it can cycle through. The first few speeds of the AutoCool are significantly quieter than the Maradyne half speed. In fact, I had to put my hand behind the fan to verify that it was running. Other benefits are that it is made in the USA by an Army Veteran, carries a 1 year warranty, has a hook up to easily install a manual over-ride switch, and Darryl (the AutoCoolGuy) offers excellent customer support. Downsides of the AutoCool is that it is rather large and thus mounting locations are limited, and it is more pricey. I ended up going with the NB50 ($190) which is their Non-Buzz unit, but if they had the AutoCool 55 ($160) in stock I would have probably used that one as I am not sure if the Non-Buzz feature is necessary and the AutoCool 55 appears to be a little smaller. https://www.autocoolguy.com/

I installed the unit on the passenger side F panel and I did make some alluminum covers to hide the wire connections.