duckdudess
duckdudess

Installation of 12” SPAL fan with Massive Mounting Brackets:

My son and I completed the installation of an electric fan in our 1970 Chamonix 2002. As with most things with this car, it wasn’t particularly difficult. It did require a little research (on this site), access to a couple of wiring diagrams, a small pile of parts,and a modest level of problem solving skills.

There is an excellent “how to” article by Zenon Holz at this link http://www.zeebuck.com/bimmers/bmvseite/)and a great wiring diagram from Shaun and Zenon at this one: Electric Fan Wiring He obviously has better than average electrical and fabrication skills, and I chose to go a simpler route and bought parts to do the job.

First though, to describe the problem. It was not cooling the engine. That problem was solved with a new thermostat and water pump. I was also bugged by a small dribble of coolant out of the base of the plastic neck on the 320i (?) radiator and I noticed that the tips of the fan blades were worn off from contact with the radiator. So I replaced it with a 3 row Silicon Garage radiator. Temperature ran about 205 degrees on the VDO gauge and showed about 2:00 o’clock on the stock temp gauge. So far so good.

However, one day I noticed that the brand new radiator had been in contact with the fan. Not just wearing off the tips of the new fan blade like it had on the 320i radiator, but lightly marking the radiator fins (see picture).

After talking to a mechanic friend and searching this site, one of the suggestions to a post was to heat and bend the fan blades to provide more clearance between them and the radiator. So I did. Bought a heat gun, set it to 1200 degrees, and bent each blade about .5” back. Voila, more clearance. I reinstalled the fan, took the engine up to 6000 RPM and while the fan blades flexed forward, there was plenty of clearance.

Problem solved? Nope. During spirited driving on the highway I smelled what seemed like burning plastic. Upon inspection, it was clear that the fan had hit the lower edge of the top radiator tank. My assumption was that the fan had flexed forward during one of my high RPM moments and the blade bending process had weakened the plastic, causing it to flex forward into the radiator. So, my next step was to cut down the fan blades with my trusty tin snips , the theory being that the shorter blades could never flex enough, no matter what the RPM, to chew up Curt’s radiator. The amazing thing is that this didn’t affect the cooling ability at all.

For those of you that know moles…they are pesky critters that love to hunt insects and grubs and in the process wreak havoc with your yard. Some people flood their tunnels, some people use poison smoke, but I trap them. I want positive confirmation that the problem is solved. Same with this fan problem.

I assumed that the fan was the problem. Upon reflection, I think it was a small front end collision sometime during this car’s life that closed the gap between the radiator and the fan just enough to cause contact during the right circumstances. Those circumstances I believe now, had nothing to do with hard acceleration and fan flex, but exactly the opposite. I concluded that the contact occurred due to the inertial force of the engine under hard braking while the rest of the car is slowing. This may be due to the stock rubber motor mounts that I installed to get rid of the steering wheel vibration caused by the urethane mounts that were in the car when I bought it. In fact, during the day of spirited highway driving described above, I did indeed jam on the brakes at high speed to avoid a sudden slow down ahead of me.

In any case, I decided that I could either replace the nose to improve the clearance and correct the previous repair or install an electric fan and eliminate clearance as an issue. Seemed like an easier and cheaper solution as well as getting rid of the (unnoticeable to me) power loss from the stock fan. I still ended up with a new nose in the garage attic, but that’s a different story.

So, on with the fan installation. I read all the FAQ’s, Zenon’s article, and ordered some parts:

12” SPAL 1360 CFM pusher fan.

$112 - Fanman part #2030

Hayden electric fan control, variable temp setting, with a probe temperature switch.

$ 36 - Summitt Racing Hayden #3647

Massive mounting brackets

$ 75 - Massive

Manual on/off switch. 30 Amp

$ 3 - Radio Shack

Miscellaneous electrical connectors

$ 3 - Radio Shack

First, I chose the probe style switch because I had nowhere to put one more temperature sender. The coolant neck had the stock sender plus I drilled and tapped the spare boss for the VDO gauge and while I considered the bung at the bottom of the radiator, all the advice said to take the temp at the top, where the coolant was the hottest. The choice then was some kind of inline hose fitting or the probe. I picked the probe.

I also chose the Massive mounting brackets even though they were pricey compared to the other $5 dollar kits but they came with one thing the kits did not: Lee’s phone number. It came in handy and is the reason I am writing this note.

First step was to drain the radiator, remove it, the fan and the front grills. The brackets were then installed on the fan (see pictures) and the fan+brackets slipped inside the nose through the grill opening. First problem: the fan bracket runs into the right side nose supports preventing the bracket from aligning with the upper right radiator mounting hole. Strange thing with Lee’s kit: it came with both screws and clips like the stock radiator mounting set up as well as bolts and nyloc nuts. I used the bolts and nylocs to mount the fan to the bracket and could have jettisoned the stock radiator screws and clips and used the bolts, but I was wondering why Lee included the new clips and screws. So I called him.

It turns out that which was intuitive to the designer was no so obvious to the untrained user. I was trying to mount the fan to the front side of the sheet metal wall, on the other side of which was the radiator. But that nose support was in the way. So Lee’s design really intended the fan to mount on the same side of the wall as the radiator, held in by the same screws and clips as stock, which he had included in the kit. Got rid of the problem with the nose support. Presented another one however.

The 12” part of the SPAL fan dimension is the diameter of the fan blades. It also turns out that the size of the opening in the wall in front of the radiator is 12.25 “, or so. Sadly, the housing on the SPAL fan that holds the fan is 12.5”, a bit too large for the opening (see picture). Now , if the fan were in front of the wall, that would be no big deal. A little surgery on Lee’s gorgeous aluminum bracket and it might bolt right up with the nylocs and bolts provided. However, it would also have left a gap between the fan housing and the radiator causing the pushed air to exit out the sides instead of being forced through the radiator. So, I solved this problem with a little sheet metal modification to the wall in front of the radiator. I cut off .25” on the top with my Dremel tool and cleaned it up with a file. The fan now fit through the hole and the mod was invisible once everything went back together. See pictures.

The fan is now sandwiched between the radiator and the wall using the stock radiator mounting. The fan housing is directly on the radiator so no air escapes while the fan is in operation.

If would have helped if I had thought to insert the probe though the radiator before I installed the radiator. But I didn’t. I wanted the probe and its wire out of harms way so I took out the radiator and installed it from the front. 2.5” opposite the upper left radiator bracket mounting hole. This allows it to the clear the sheet metal wall and not hit the Massive fan bracket.

Last step was the wiring. The Hayden kit came with a variable temp controller, relay, wiring for 2 fans, an A/C wire, the probe and a fused power line to the fan. A couple of comments. The fuse holder has no cover (not perfect) and the kit included minimal instructions, so I still don’t know the difference in temp between fan on and fan off. Testing will tell. Lastly the probe wire was barely long enough to reach the radiator from the spot where I wanted to mount the relay. That problem solved itself. I’ll explain later.

I mounted the fan relay below the horn relay which is the round thing next to the voltage regulator on the left inside wheel well. I picked this spot because it was close to the battery, had a good ground location and the green/blue horn power wire was right there on the relay. I screwed the fan relay to the wheel well, connected the 12 v power feed to the green/blue relay terminal using one of those two into one spade adapters, connected the fused power line to the fan, ran a new ground wire to the fan harness, connected the pink wire from the relay to the battery’s positive terminal, cut off the wires for the 2nd fan and the a/c and was almost ready to go.

I decided to add a manual switch inside the car. I fabricated a little aluminum bracket and used the 5mm x .80 screw hole on the bottom steering column cover to mount it. I grounded it and ran a wire to connect to the radiator probe. I simply used one of those blue crimp connectors that allows you to connect a new wire (from the manual switch) to the existing probe wire without stripping cables.

Great idea it seemed until I discovered that the fan would never turn on unless the manual switch was on, which meant that the relay circuit was doing nothing. It turns out that the blue crimp connector had severed one of the two wires going to the probe. Well, the probe wire was too short anyway, so I cut it, spliced in two new lengths of wire left over from the relay harness (the two probe wires are not interchangeable. Once severed they need to be reconnected to their original twin on the other end of the splice) and then had to figure out which one of the pairs to connect the switch wire to. Looks simple in Xenon’s wiring diagram, but it wasn’t obvious to me, so I tested the manual switch wire on each splice. One of them worked and I soldered the switch wire to it, separated the splices from each other with electrical tape, bundled the splices together then cable tied them into the wiring loom that ran to the headlights and horns.

All of that seemed to do the trick. The fan was set to keep the car at 200 degrees and so far so good. I have not road tested this to see if I can cause any catastrophe, but I left that task to my son, who of course always drives in complete control (just installed a new rim after he “slid on the leaves” into the curb).

I hope this helps the next person that tries this installation. Overall, it took a couple of hours, one phone call to Quebec, a little trouble shooting, but I now think my fan clearance problem is solved.

Someday, I will put the new nose on the car, but that can now wait until the 5 speed and LSD , which are sitting on the work bench, get their turn.

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