Well, here I go... pulling the motor.

thesameguy · **Joined:** Sat Oct 01, 2016 8:24 pm **Posts:** 652

Or, leak NOT cured. The issue is/was the cooler itself. It was leaking ATF from the driver's side end tube. Being part of the AC condenser, the replacement part is very expensive ($300) and, possibly, discontinued. Super.

Since I'd had the original cooler lines modified, I was left with a nice 24 degree FlareLok compression fitting on one side, so I used an adapter to go from that to standard AN 37 degree:

It's a very clean, reliable connection.

I then installed a Setrab 50-910-7612 under the bumper:

This cooler should be quite an improvement over factory - it's about the same surface area but about 3x the thickness. I have one tiny little detail to attend to this afternoon, but then it's ready to go.

WWDiesel · **Posted:** Fri Jul 30, 2021 12:34 pm

That is a good location, that is where I mounted my 10 plate stacked oil cooler by Derale using AN fittings as well.
Once suggestion for your location, add some protective expanded metal over the cooler for protection from rocks, road debris, etc..
Cheap insurance! :wink:

user113 · **Posted:** Sun Aug 01, 2021 3:14 pm

I love these redneck modifications.

WWDiesel · **Posted:** Sun Aug 01, 2021 5:57 pm

user113 wrote:

I love these redneck modifications.

Necessity is the mother of all inventions! :jester:

If they don't make something, engineer it and build it.... :idea:

fjdiesel · **Posted:** Mon Aug 02, 2021 11:04 am

thesameguy wrote:

Yep, that worked perfect!

Not much to see, which is the way I like it!

The little electrical doodad in the second picture is just hanging out right now - I want to have access to it for a little bit before permanently placing it under the dash.

The recap:

Electric fan from a BMW F30. This is a 600w, DC, brushless, PWM-controlled fan. It moves an insane amount of air at full speed.
Re-using the BMW's 70a (!) relay
Power for the fan comes directly from the positive junction on the fusebox, through a 60a maxi fuse, to the BMW relay
The relay is triggered by the factory ASD relay, such that when the key is on the fan is "enabled," but will run only with a valid PWM signal OR if the PWM input is left floating (failsafe)
Y adapter for the factory ECT sensor sends ECT output voltage to the cabin

Inside the cabin is this thing:

https://www.ebay.com/itm/VARIABLE-PWM-F ... Swxv1epmGn

It gets power from the ASD relay, is grounded to the stud by the ECM, and is wired to the PWM fan and the factory ECT sensor.

At 195F degrees it runs the fan at minimum speed (about 10%) and it has a linear ramp to about 210F degrees where it's at full speed. In my manual testing, with ambient temperatures at 70F, the fan running at 30% will shed heat *fast*. I'm thinking it will never get to full speed. If that turns out to be true as it warms up around here, I'll raise increase the activation temp a bit higher. I just didn't want to run the chance of runaway temps until I know how this does when it's 100F outside. Since the fan relay and control module are both powered by the ASD relay, they can run for run for a short while after shutdown... I might add a capacitor to give me ~30s of runtime just to take the edge of in hot weather shutdown, but I'm not sure that's useful.

Total cost on this was about $280. I'm (initially) very happy with the result. The engine warms up quicker since there's no mechanical fan always spinning. Fuel economy is a bit better. It runs quieter without the mechanical fan, and at <50% speed the BMW fan might as well be silent - multiple times I've had to pop the hood to be sure it's running. Being a PWM fan, there's no huge inrush current, and since (so far) it spends most of its time at 20-30% speed, it's only using a few amps keeping engine temps under control. Access to accessories & the serpentine belt is vastly improved. This whole thing was a win, so I guess I owe FFD a big thank you for not responding to my emails and setting me off on adventure. :/

Awesome write up on that fan. Are you still happy with it? If so, I think I am going to start pulling parts together to do that.

thesameguy · **Joined:** Sat Oct 01, 2016 8:24 pm **Posts:** 652

I would say 95% satisfied.

I've been running this setup for however many months, from days where it's 60F ambient to recent days where it's 110F ambient. Cooling performance is extremely good - I've never had temps go beyond 203F and extremely rarely beyond 201F... the 203F scenarios are hot weather, sitting in traffic, and doing stoplight drags. Temps will spike and then come back down... very predictable.

The 5% unsatisfied is:

1. The window between "start temperature" and "max temperature" is slightly too wide for my taste. This causes the fan to start a little earlier than I'd like and not ramp quite fast as I'd like. The result is that when driving slowly in hot weather, the fan may be on at ~10% or so, but not actually doing anything which is just wasteful. It's not worth losing sleep over... 10% is basically silent and can't be more than an amp. Still, it's not perfect. I would rather have the fan come on a little more aggressively a little later.

2. The AC override runs the fan at 100%, which on a 600w fan is nutty fast. As a result, I'm not using the AC override, I'm still using the factory 2-speed electric fan to handle that work. In an ideal world, I'd be able to run that 600w fan at 50% or something and dump the factory electric fan entirely.

I'm not losing sleep over any of these. I've yet to have a reason to regret this choice. Temps are incredibly stable which should translate directly to long head gasket life.

FWIW, I also installed these controllers on my 1985 Saab and 1986 Merkur ... slightly different approaches since I used different fans, but the same controller, same sensor, same logic.

Also, there's a rev 2 of this controller coming out in August that will fix #2 by having a user-settable 50% or 100% switch for the AC override. They also offered to make a special run of controllers that would fix #1 for me - so I may go for that. I would retrofit all three cars.

fjdiesel · **Posted:** Mon Aug 02, 2021 9:04 pm

Thanks for the info and update. I won't be ready until this winter, so please keep us informed if the come out with V2 or you have a special run made. I would be up for one. Thanks again.

Well, here I go... pulling the motor.

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