AC is going on the sweptie soon, which means the extra load on the motor is going to really hurt drivability unless I make an upgrade. Gears are on the menu, but first, the truck came stock with a shroudless direct drive fan, hugely parasitic and not great at cooling either.

A Proform electric fan (https://www.summitracing.com/parts/pro-67017/overview/) is $114. On the other hand a low duty thermal clutch+mechanical fan from Hayden comes out to about $60, with an extra $35 or so for a universal shroud. I recently learned here that the old alternators don't put out much more than the fan would draw... but being thermostat-controlled, the fan would only be on at or around idle, anyway. The clutch fan obviously won't draw amps, but on the other hand, it will only save about half as much power as the electric fan, and the shroud between the radiator and fan will be a lot bulkier than the radiator-mounted electric unit. On the other other hand, there's no wiring involved.

What all upgraded fans do you guys have on your motors?

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'69 D100, 225 SL6, A745→NP435

An electric fan will have a large amp draw when it first starts but then the amp load will drop significantly once it is running. You can shop around and find electric fans that have a lower initial amp load and a very small running amp draw. Try and find a setup with two smaller fans instead of one large fan.

If I were in your situation, I would keep your stock fan, invest in a fan shroud that covers the whole radiator and necks down to place the fan right in the middle of the engine side opening with about a 1 inch gap on the sides of the fan. I would then invest in a pusher fan mounted on the front of the AC condenser that was wired via a relay to come on when the engine temp gets too high and when the AC compressor comes on. Rather than buy aftermarket, I would get an OEM electric pusher fan and relay wiring from a junked modern car. Try and find one with an integral shroud for impropved efficiency.

Start reading here; that's chapter 1. There's a link to the next chapter at the bottom of each page. Chapter 5 is about fans and why you might want to pick one kind over another. An electric fan will require significant electrical system upgrades, and a cheap off-brand electric fan will raise dependability issues as a matter of "when", not "if".

Adding A/C effectively will require thoughtful selection and specification of components, and it will also require upgrades that you might not have thought of as part of the project. The cooling system (not just the fan) has to be up to the task, and the truck is a "solar oven" that needs insulation and window treatment if the A/C's to have better than a snowball's chance in hell of doing anything like a good job for you. See here. You'll want a parallel-flow condenser; it won't be expensive. See here (and threads linked there) and here.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

Fine series there, Dan! Loads of good info in a well-written package.

Thanks, Reed.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

Thanks Dan and Reed!

Reed, am I correct that you're suggesting two fans (stock pump-mounted and electric pusher) will be necessary to keep the engine cool with AC running? Especially with the stock solid fan, I imagine that would result in a lot of parasitic power loss. Shouldn't I upgrade to an idle-lock clutch (as per Dan's link) with a junkyard blade? I definitely agree that a full-coverage shroud should work better than the semicircular universal kits.

Dan, I went with AC from Nostalgic Air based in FL. I'm using this kit. Was not easy on the wallet but I figured if there was one upgrade I could use right away... It uses a modern compressor and appears to have a parallel condenser unit. I can get tint done right for relatively low cost around here. When you say electric fan(s) require significant upgrades, do you just mean alternator and relay or is there more?

I thought Proform was a relatively established brand. Since it is a kit w/ thermostat I thought there might be less chance of me botching the wiring. Would your overall recommendation be the same as Reed's to go with an electric pusher and a solid/clutch fan?

Despite the poll answers, I'm getting the impression that idle-lock thermal clutch and junkyard fan + full shroud might be the way to go right now...

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'69 D100, 225 SL6, A745→NP435

Necessary? No. The optimal solution? Probably not. My recommendation to you was my attempt to balance ease of installion with costs. Dan is correct that any electric fan really requires a charging system upgrade on a vehicle as old as a Sweptline.

If money were no object and I was in your position, I would upgrade to a later Nippondenso 90 or 120 amp alternator, upgrade the charging wire, bypass the ammeter in the dash (install a voltmeter instead and don't run the entire charging system output through the ammeter), install an electric puller fan with a shroud, and install an electric pusher fan that comes on whenever the AC is on. But that is very expensive and likely not necessary.

A cheaper solution would be the charging system upgrade with a dual electric fan set- either both pullers or both pushers. One fan runs whenever the AC is on and the other runs to control engine temp. Or a low speed/high speed setup where low speed is for temp control and high speed is for AC airflow across the condenser.

An even cheaper solution would be a single large electric fan (with charging system upgrade) or a clutch fan with a shroud. That has worked on millions of vehicles for decades to provide adequate cooling for the motor and the AC system. Having a booster fan to circulate more air when the AC is turned on helps keep the AC cool in stop and go traffic but it is not absolutely necessary.

The absolute cheapest and easiest solution is to upgrade to a clutch fan and fan shroud. No charging system upgrade needed, but you won't have the benefits of an electric fan.
Weigh your options carefully. If you are going to be adding more electrical upgrades to your truck (lights, stereo, etc...), you might as well upgrade the charging system. The upgraded charging system allows you to use an electric fan. I don't see any reason why the stock solid fan with a fan shroud would be unable to keep the engine cool and move enough air for the AC to work. There are options to make the system work more efficiently at all engine speeds (i.e. electric fans, clutch fans), but the stock fan and fan shroud should be sufficient provided the rest of the cooling system is in good condition.

If that's Reed's suggestion I would respectfully disagree. The correct fan count is one (1), properly selected.
That would be a good idea.
Also a good idea.
Good. You will still need to insulate and glass-treat your truck.
You can't just throw a big alternator in without upgrading the rest of the charging circuit. See here.
All but the super-ѕhittiest junk has a brand. Most brands are designed to make you think/feel they're legitimate. "ProComp" and "ProForm" and dozens or hundreds of other brand names have no substance behind them; they're generic trinkets brought in by the full containerload from China, with a brand slapped on 'em by an American fast-buck artist who then wholesales 'em to the likes of Jegs, Summit, Amazon, Pep Boys, etc. Even brand names that are legitimate don't necessarily guarantee a good product; see here and here. If you're going to put in an electric fan, get one from a reliable brand — Spal, Hayden, and Flex-a-Lite are three examples — or, usually better and cheaper, fetch a thoughtfully-selected original-equipment electric fan from a wrecking yard. The last (most recent, also final) one I sold was this one.
Certainly the fastest, easiest, and most cost-effective. Make sure you get a straight (unbent) fan blade and put a new good-quality clutch in it, and you cut your dependability risks down to almost zero.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

Ah, I thought you meant to do both at the same time rather than one after the other. I'm already running some 12v outlets, a stereo, and a tach off the ammeter bus terminal, so you're right that I should probably upgrade the charging system...
That's good to hear. My fixation on the clutch fan is as you said about getting the system to work more efficiently. As it is I'm not making much power and wouldn't want to lose any more. I think I'll get a good clutch and shroud to get some extra efficiency and cooling, respectively, and once I've upgraded my charging system and alternator (which I should eventually be doing anyway) the electric fans will be on the cards.

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'69 D100, 225 SL6, A745→NP435

Hmm, I'll definitely be keeping an eye out for that one whenever I hit the junk yard. For now, Hayden clutch it is.

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'69 D100, 225 SL6, A745→NP435

www.hollanderparts.com
www.car-part.com (as of this writing, the top result is a fan assembly off a 5.9, which is the one you need, for $100)

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

FYI- when this occurs (Dan disagrees with me), the wiser choice is to listen to Dan. He has forgotten more about this stuff than I will ever know and is far more accurate than I am.

Thanks, Reed, but hold on a sec. I overstate the case when I call one the "correct" number of fans. There are plenty of original-equipment and aftermarket 2-fan setups; it can and does work. The reason I recommend against it is higher parts count = more failure points and two motors = very high current draw. But if those two issues are addressed and there's some other reason a particular setup works best with two fans, use two fans!

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

Zac,

Terrific advice being given by Dan and co. here as usual.

I installed AC on my stock 1970 Aussie VIP Chrysler in Nov 2016. Two words - LOVE IT! I used the Nostalgic Air Compressor Mount Kit with great success. I did need to use a 3" water pump fan extension to clear the triple row crank pulley (power steering soon...) and extend one of the supporting brackets one inch.

I also took the opportunity to recondition/upgrade the radiator (2 core) and set it 1" further away from the motor for clearance. I used a Valiant 7 blade V8 fan (electrics are being upgraded so an electric fan is an option in the future if I want) and no shroud as I wanted it to look reasonably as stock at this point. I upgraded the cabin insulation, but still have improvements on that front to make.

I sourced and installed an evaporator and Sanden 508 style compressor. The rest was handled by air con specialist who took care of sourcing and installing the condenser, drier, lines (hard and flexible to my preference), gassing and electrical.

End result is a very good reliable system that does the job extremely well and was within my budget... and looks reasonably stock. My temps can creep up a little on 100 deg F days if I'm stuck in traffic for a long time, so I'm contemplating a shroud and perhaps a pusher electric fan in the future.

My advice is to be patient and get the best quality parts, expertise, and maximise each facet (overall design, cooling, electrics, insulation, etc.) of the installation as you can afford.

You won't regret it. Good luck!

Mario

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Love cruising in a bare metal Val!