Chillin' Louie (Part IV: The Condenser and Fan)

As I and many other folks have said, part of the recipe for upgrading performance of any vintage a/c system in any car is to replace the old-school serpentine-flow condenser and fan with the largest modern parallel-flow condenser you can fit in the nose, and the largest fan you can fit on the condenser ("big enough to suck a schnauzer off the sidewalk" is the way I've often put it). In this series of articles, I've been light on theory, as you can read about how an air conditioning system works in my book and many other places, but the condenser is basically the a/c's radiator, the place where it dumps the heat that's extracted from the passenger compartment. The more heat it can dump, the better. The old serpentine-flow condenser had one thick bent tube that snaked through it (hence the name), whereas a modern parallel-flow condenser has many small tubes, allowing more refrigerant to come in contact with more metal and thus dump the heat to the air.

Original Behr serpentine condenser and modern parallel-flow condenser

This is now the sixth 2002 I've done a/c rejuvenation or retrofit in. In each one, I've handled the condenser and fan differently, but consistent across them is the question of size and mounting.

Condenser Size

I and others have posted here on the FAQ about the question of the largest parallel-flow condenser that can be fit in the nose. It's been pretty well documented that a 10x18 condenser will fit between the horn brackets without needing to cut any sheet metal (though you may need to trim the bracket on one side of the condenser. I fit an 11x20 (mistakenly listed as 11x21 in my a/c book) by cutting both horn supports.

But in nearly all those posts, folks were looking at it from the standpoint of mounting the condenser vertically to the nose wall directly in front of the radiator. In this recent post, I revisited the issue by asking if there's larger size that can be fit if you instead angle the compressor behind the hood supports. By taking a piece of particle board and cutting it down until it fits, and taking into account the fact that the stated width measurement of a condenser is the outer tube-to-tube width, not the bracket-to-bracket width or the bracket-to fitting-edge width (you need to add on about 1.5 inches to the spec width), I determined that when you increase the width, you rapidly become unable to make the turn when you try to put the condenser through the radiator hole, but a 10x20 condenser would probably fit behind the hood supports. Unfortunately, neither that size nor 10x19 appear to be click-and-buy available, so I fell back to the well-vetted 10x18. I purchased mine on coldhose.com.

10x21.5 piece of wood simulating a 10x20 condenser fitting between the horn brackets and the hood supports

However, there was still the question of whether to mount the condenser vertically to the nose wall as I had every other one I'd installed, or try something new and mount it behind the hood supports. As with many other things like this, I wrote up the pros and cons in a spreadsheet (because, yup, I'm that much of an ex-engineer):

In front of radiator pros:

• Simple straight shot mounting with standoffs or rubber vibration isolators through nose wall

In front of radiator cons:

• It's close to radiator in terms of heat from one affecting the other
• Need to be careful about radiator mounting screws puncturing condenser (been there, punctured that)
• Access to top hose fitting partially occluded by horn bracket

Behind hood support pros

• Something new to try
• Physically separated from radiator both in terms of air flow and puncture from bolts
• Free access to hose fittings
• Can mount a Spal fan on the front of the hood supports where it fits perfectly

Behind hood support cons

• Less clear how to mount it; probably need to make some sort of bracket
• Air flow at speed may not be quite as good due to lower part of condenser being below kidneys

I thought I'd try the hood support mounting just to do things a different way. What stopped me was nothing in the above list—it was the fact that, as part of all this digging about in Louie's nose, I discovered that there's a lot more rust there than I thought. The bottom of the left hood support is rotted clean through to the point where it's detached.

Most surprising. And disheartening.

The detachment didn't make me afraid that weight of the condenser and fan on it would cause problems, but it did make me concerned that it might bang around, or vibrate when the fan was on. So I fell back to a conventional vertical mount in front of the radiator nose wall.

Mounting

As I've said, I've done this with 1"-long nylon spacers, as well as using the rubber vibration isolators that are used on 2002 air cleaner housings and tii injection pumps. I prefer the rubber isolators as they eliminate the possibility of fan vibration coupling through to the body of the car, and for a while, I seemed to have an inexhaustible supply of them, but this time, when I checked, the only ones I had were old and cracked, and I had nylon spacers left over from a prior installation, so I just used them.

You do want to space the condenser off the nose wall, both to get it away from the heat of the radiator (and vice versa) as well as to help assure that the radiator bolts won't puncture it (I've done this; see below), but the downside is that the further you move it away, the sooner the bottom of the condenser will run into the angled hood support, giving you less leeway with how far down you can mount the condenser.

Totally not kidding about having punctured a condenser with a radiator bolt.

Why do you care about having the bottom of the condenser further down? Don't you want the whole thing slid upward to help with air flow through the kidneys? Well, yes, but the other factor here is the fan. I'll get back to the fan itself in more detail, but as far as how it factors in with the condenser mounting, on a 2002 I usually use a 12"-diameter fan, as that maximizes the use of space between the hood supports. The condenser is only 10" tall, though, so the fan overhangs at the top and bottom, and it's by more than 1 inch because the overall housing of the fan is bigger than 12 inches. You can plan to center the fan exactly on the condenser and mount the pair against the nose wall, but when using standoffs, you may find that the bottom of the condenser won't go down far enough, and you wind up having to reposition the fan so it hangs further off at the bottom. It's not really a big deal, just be prepared.

As far as the actual mounting, you're likely going to have to drill holes in the nose wall. I've seen photos here on the FAQ of people who've hung the condenser from the horn brackets, and I suppose that another advantage of mounting it to the hood supports is that you could fabricate brackets that mount it to the 13mm bolts or the hinges and not have to drill holes, but most folks just mount it to the nose wall and drill holes. I usually slide the condenser as far to the right (driver's side) as it'll go and try to get the mounting points off the little shoulder around the radiator cut-out. 

You can futz with it for hours, but at some point, you just hold the condenser up so that the top hose fitting is about in the middle of the space made by the horn bracket, so there's clearance for the hose connector, mark the mounting points on the right as best you can with a Sharpie, center-punch them, drill them, and bolt them. I use M8 bolts with 10mm heads so the hardware feels in harmony with the other hardware on the car (and gives me the opportunity to lose another 10mm socket :^). This means having to drill out the holes in the condenser bracket to enlarge them slightly, but it feels right to me.

Upper hose fitting about in the middle of the space behind the horn bracket

Upper right hole drilled and test-fit. Note from the black Sharpie mark above it that I was off by one, as I couldn't get the bottom of the condenser as low as I thought due to it hitting the hood supports when stand-offs were used.

You're probably going to need an extra-long drill bit to reach in and drill from the front, as there's really no way I'm aware of to mark them and drill them accurately from the back. And the drill bits really tend to wander. My latest technique is to mark them, center-punch them, then use a Dremel tool with a pointy grinder bit on it to grind a little pilot hole for the drill bit. Do it first with the upper right mounting hole (as viewed from the front), put the bolt and nut through it, get it as level at the top as you can, make sure that the upper left hose fitting has clearance in the horn bracket, then mark and drill the bottom right.

On the left side, it's a little more complicated, as making the right side flush with the horn bracket pulls the left condenser bracket over the edge of the nose wall, so you almost certainly need some sort of side-mounting bracket to extend it over. One of the really frustrating thing about condensers is that their hole spacing doesn't appear to be standardized and is very rarely listed in the specs. The same is true with the rectangular multi-hole universal brackets that a/c companies sell. I bought both the condenser and the side-mounting brackets from coldhose.com, figuring that that way the hole spacing would match, and incredibly, they didn't.

Be aware that, on the left (passenger) side, your bracket and the holes you drill for it have to clear the radiator mounting ears. Here, I didn't, and had to redo it by adding an extra bracket to space it over further. Idiot!

This looked great from inside the nose, but...

...when viewed from the engine compartment, the head of the bolt was right where the passenger-side radiator mounting ear has to sit flush. D'oh!

Second attempt with another bracket to space it over.

Jim Gerock commented on Facebook that this looked like the condenser is supported in two places on the right side but only supported in one place on the left side. Well, sort of. I know Jim to be thorough, meticulous, and a first-rate mechanic, so I take his observations seriously. The condenser bracket itself on the left is shorter than the one on the right because the hose fittings are on the left. And it's difficult to drill at the very top and very bottom because of drill access. Plus, as you can see, I had to trim the left bracket slightly to get clearance around the horn bracket, so it's not like I could drill the hole several inches higher even if I had access to. The brackets themselves are pretty rigid and bolted together in two places. The whole mounting structure probably isn't as rigid as it would be if the mounting points were fully extended to all four corners, but it is mounted at four points, and it doesn't weigh very much.

The Fan

I use only Spal-brand fans. You can find cheaper ones that make all sorts of claims about cubic feet per minute (CFM) of air flow, but only with a manufacturer like Spal or Mishimoto would I actually believe them.

Spal's 12-inch pusher fans are in a table below. The costs are from Amazon. As with everything, there's a lot more about fans in my book.

The go-to 2002 fan for me is the 30101505. Despite my saying that I want a schnauzer-sucking fan, most of the time when I want a/c in a vintage car, it's because I'm road-tripping as opposed to caught in traffic, and the 30101505 has seemed like a good trade-off of profile, weight, CFM, amperage, and cost. Keep in mind that, on a vintage car like a 2002 with an anemic original alternator, you may need to upgrade the alternator if the fan is actually pulling 20 amps. I want to measure the actual draw of the fan, but the fuse on my trusty old Fluke multimeter is only rated to 10 amps. I have an old VDO ammeter kicking around the garage somewhere. When I find it, I'll measure and edit this article here.

As with the condenser, I've mounted the fans in a variety of ways. If you use the little Spal plastic brackets that slide right into the fan housing, you can bolt the 16-inch fan directly to the hood supports. If you use those brackets and the linear metal brackets Spal sells, you can attach them to the 

condenser brackets at the sides or top. But you can also use the zip-tie-like Deraile (or other) fan mounting kit and just snock it directly to the condenser. This used to give me the heebie geebies, but it's so easy to do that, as long as the fan is relatively lightweight and the car isn't driven offroad or on really rough pavement to throw the fan around, it seems to work out well. That's what I did here.

I did have two unanticipated issues. The first was that, because I wasn't using the little Spal right angle brackets (I thought I had four, but didn't), I instead zip-tied directly to the holes in the fan frame, and there's not enough room there for the round Deraile slide-on connectors. I trimmed them with wire cutters.

The trimmed connectors

The second issue was that, having mounted the fan on the condenser, I found that I couldn't pass the pair of them through the nose together. I had no recollection of ever having this problem before. I cut the connectors, bought another set, put the fan through, then the condenser, then mounted them.

But, finally, it was done.

Yes I trimmed those zip ties.

The view from the back with the pads for the backs of the Deraile zip ties.

Next installment: The Clardy evaporator assembly.

--Rob

(My a/c book Just Needs a Recharge: The Hack Mechanic Guide to Vintage Air Conditioning can be purchased here on Amazon, or personally-inscribed copies of it and my other books can be purchased directly from me here.)