Here is my final update:
I gave up on my volvo fans. I am towing too heavy now moving across the country and back in the next few years and need the CFM of a mechanical fan. They worked great in a light duty towing, and daily driver on road setup, but not when you're pushing the truck too hard in the dirt under the desert sun, or hauling equipment to a ranch on winding backroads up and down big grades.
I also gave up on the stock 3rd gen electro-hydraulic fan clutch after cutting another set of wires with the OEM unit I installed to get across the country on my first outing into the woods of the northeast.
Instead I have installed the following parts, ordered from RockAuto:
1999 DODGE RAM 2500 PICKUP 8.0L V10
HAYDEN 2791 Radiator Fan Clutch $ 38.79 $ 0.00
2001 FORD F-250 SUPER DUTY 7.3L V8 DIESEL Turbocharged
MOTORCRAFT YA225 Radiator Fan Blade $ 71.79
Total delivered to my door was $115.
1999 V10 severe duty fan clutch had the correct thread pitch, the 7.3 fan bolted right up with some metric hardware, and the fan leaves a ~1" gap to the shroud.
Haven't had any issues at all, but its not summer at 24000lbs gross yet.
If anybody is interested in my fan setup, it worked when pulled, wiring is complete, and it comes with an extra fan/motor. $180 plus the ride.
OK. Here are the details of my fans/shroud setup.
16 gauge galvanized sheet, 1 inch shroud depth. 26.25"x 29.5" inside dimensions. I used a sheet metal brake to bend the edges, and a plasma cutter to cut out the circles. (<$70 material cost)
*Volvo 2 speed fans and controllers, I took mine from a 97 S70 and a 98 V70XC. Any late 90s era volvo should work, but i took mine from turbo cars. ($20-50/each)
*Hollister Road 1.75" 304 stainless pipe with M14x1.5 bung and a 1/2 NPT bung for a coolant bypass dump. You could do 2" as well, must ask for custom 2 unit ($55)
*Trunk lid weatherstripping from junk yard
*BMW 91/99C low/high thermister BMW# 61311378073
*BMW wiring harness parts for thermister:
-1x 90 degree connector BMW# 61131378412
-2x high/low trigger wires BMW# 61130007445
-1x ground wire BMW# 61130007446
*Volvo Relay PN# 1398845 (just take these with the fans at the JY, plus all the wire you can get your hands on)
*2x Standard 5 pin relays
*Good quality heat shrink electrical connectors (
Wiring Diagram. I added another relay wired the same as the IGN switched relay to use a hot A/C control wire tap to trigger a ground which I tapped into the High speed control circuit
Cut to size, 1" edges bent, 15 7/8" diameter holes cut
Divider welded in and trunk lid weather stripping mocked up
mounting tabs welded. If I did it again I would weld them flush with the shroud height, butt welded to the edge to make installation easier. used the factory fan shroud for dimensional reference
Fans riveted on, relays and controllers also, plus a coat of paint.
More info is found scattered through this thread, but this has been the bulk.
Good luck, and may cool temperatures be with you.
Begin Original Post:
I installed the Flex-a-lite fans after my stock clutch wires decided to get in the way of the fan - ruining the radiator, fan, and clutch.
Not happy. The flex fans work fine on the highway, but at low speeds chugging up long winding back road hills they dont cut it, not to mention raging in the dirt... I kept pushing it one time to see if the temps would stabilize, but quit when I hit 245
I Need ideas. I was in a pinch and needed to get the truck back on the road, but now have time to around and figure out a real solution.
I've installed a set of Ford Windstar fans on a project before, and have heard about the legendary Taurus fans. I am contemplating trying to offload these things and getting a pair of Taurus fans....
Need MOAR CFM!