Evaporator: second opinion from the Mud hive mind

[Marvelicious]

I'm midway through my AC rebuild... My compressor seemed to be going out so I decided to replace everything but the lines. When I ordered, the Denso evaporator was out of stock almost everywhere and priced like it was made of gold where I could find it. I made the decision to try off-brand parts on it and the condenser based on some decent experiences with Chinese heat exchangers of various other types. I stuck with Denso for the compressor and expansion valve because I figured those were sensitive parts. The Nissens condenser turnout out to have a slightly smaller footprint, but fit well and actually a bunch more more coils (Is there a better term? The flattened flow tubes from one upright tube to the other), so there is actually more surface area in contact with the air. I'm thinking it's a wash at worst and possibly and upgrade.

Now, the other part that I'm actually wondering about. The GPD evaporator core is around 15% thinner: 3.5" thick vs 4.125" for the original. It's the same size in the other two dimensions and has the same coil spacing. Seems like that has to hurt efficiency, right? At the moment I'm thinking about flushing the everloving #@<& out of the original since it doesn't actually look too bad, just dirty. I've also got some foaming coil cleaner that I picked up for my household AC, so if it goes back in, it's going back clean.

Take a look at the pics... Anyone have any thoughts? I tend to start using AC about the time it's over 60ºF outside, so I want it to WORK.

 

[NeverFinis]

I waited and waited for the Denso evaporator to come into stock at the usual locations (RockAuto, Amazon, Partsouq, Denso Corp) and it never did. I paid nearly double the price to buy it from Ourisman Toyota as I wanted my A/C system to be finished. I suspect it isn't being manufactured anymore, or at least it is rarely manufactured.

Since it is once in a decade (or more) job, I decided to pay the extra money to get it right, rather than buying a smaller chinese evaporator.

On the other hand, the evaporator isn't that difficult to change out.

 

[jonheld]

The evap coil is simply a radiator. I would pressure test it. If there are no leaks, then clean the crap out of it and throw it back in.

 

[Marvelicious]

I waited and waited for the Denso evaporator to come into stock at the usual locations (RockAuto, Amazon, Partsouq, Denso Corp) and it never did. I paid nearly double the price to buy it from Ourisman Toyota as I wanted my A/C system to be finished. I suspect it isn't being manufactured anymore, or at least it is rarely manufactured.

Since it is once in a decade (or more) job, I decided to pay the extra money to get it right, rather than buying a smaller chinese evaporator.

On the other hand, the evaporator isn't that difficult to change out.

They don't list it as discontinued, so I suspect they make the occasional run, but you must have to catch it when it happens. So, are all the Chinese evaporators undersized?

The evap coil is simply a radiator. I would pressure test it. If there are no leaks, then clean the crap out of it and throw it back in.

A radiator that's well protected at that. I found a few failures on here when I was originally researching replacement parts, but I suspect those were mostly rust belt vehicles. They all had visible external corrosion issues. I figured I'd sleep on it, but I came to the same conclusion. I'm pretty sure it's leak free: my system was fine until the compressor started acting up. Had I opened the system up before ordering parts, I probably wouldn't have even ordered the evaporator.


For the sake of future reference for anyone else who searches this topic, I'll post pics of the Nissens condenser as well. The one in my 80 was almost definitely not original - I have a reconstructed title and my core support is a different color, so this is probably a junkyard part and for all I know was originally from an R12 vehicle. It's definitely older than my radiator. It's pretty crusty, which is why I decided to replace everything else.

Here is the old one and new compared. 21 coils vs 34 on the new one, so I'm not concerned about the change in size.

Sooooo.... anyone need a screaming deal on a never installed, slightly undersized chinese evaporator?

 

[KCCruiser]

I am also in the middle of replacing a/c components. I also found that the Denso evap was not available so I ordered and received a new OEM. The price difference between Denso and OEM (also Denso) was only about $100. It’s money well spent as the first one lasted 30 years.
The new Denso condenser, drier, expansion block, and compressor all fit like a glove. If you’ve emptied the system, you may as well just replace everything as it was probably less than $650 all in. Just my opinion and of course.

 

[Marvelicious]

I am also in the middle of replacing a/c components. I also found that the Denso evap was not available so I ordered and received a new OEM. The price difference between Denso and OEM (also Denso) was only about $100. It’s money well spent as the first one lasted 30 years.
The new Denso condenser, drier, expansion block, and compressor all fit like a glove. If you’ve emptied the system, you may as well just replace everything as it was probably less than $650 all in. Just my opinion and of course.

Eh, it's not staying out of commission any longer: ordering more parts at this point is not a choice I'm willing to make. Like I said above, I wouldn't have even ordered the evaporator if I had looked at it first.

I get what you're saying, and if I had a nice low mileage example that needed to do daily driver detail, I'd absolutely agree. I bought this as a wheeler, and while I drive it more than I thought I would, it's still a trail rig first. The odds of going even ten years without doing a motor swap or driving a branch straight through the condenser are pretty slim, so I think I'm content with the Nissens condenser and reusing the evaporator. I suspect I'm still on my original head gasket here... I'm probably going to have to tear it down at some point anyway.

 

[ZackR]

Eh, it's not staying out of commission any longer: ordering more parts at this point is not a choice I'm willing to make. Like I said above, I wouldn't have even ordered the evaporator if I had looked at it first.

I get what you're saying, and if I had a nice low mileage example that needed to do daily driver detail, I'd absolutely agree. I bought this as a wheeler, and while I drive it more than I thought I would, it's still a trail rig first. The odds of going even ten years without doing a motor swap or driving a branch straight through the condenser are pretty slim, so I think I'm content with the Nissens condenser and reusing the evaporator. I suspect I'm still on my original head gasket here... I'm probably going to have to tear it down at some point anyway.

Assuming it doesn't leak I'd clean the original evaporator and reinstall (with a new expansion valve at the same time).

When I pulled mine (July 2017) it was an absolute mess. Cleaned it up with some orange degreaser spay and a bunch of water and it still blows cold today.

 

[Gascan]

Earlier this year, I replaced every major component of my A/C system (compressor, condenser, evaporator, expansion valve, dryer, evap to firewall a/c line - because one of the two bolts corroded & broke in the threaded end of the line); I had already added an auxiliary electric fan to provide extra cooling at idle speeds prior to this. Recharged the system by weight.
Unfortunately, I don't have a thermometer to measure the vent temperature right now (gave it away to someone who needed it and haven't had a chance to buy a new one) so I can't provide you with the temp delta but the end result is night & day to the way my A/C ever blew during SW Florida summers. Cold, crisp air as soon as I start the engine and only gets better from there.
I think the biggest contributor in my case was that the evaporator fins had begun to rot/corrode and it wasn't up to snuff. Seeing as how you're already replacing damn-near every component, may I suggest you put in a fresh evaporator while you're at it.

I'm going to quote myself from a post I made a few weeks back as it seems fitting...

I ended up with a Nissens evaporator for the same reason as everyone else - DENSO is out of stock and with this economy, I don't have the coin for OEM when replacing everything at the same time - my original evaporator had rotted out and begun to leak (aluminum does corrode/rot over time and while your original evaporator seems to be in mostly-okay shape, will it outlast a fresh evaporator made out of the finest Chinese aluminum-like substance ). Having replaced it along with everything else, I have the coldest A/C I've had in memory. It fit fine and I'm not losing any sleep over it.
With that said, I'm tempted to chastise you for not buying a Denso condenser, which is in stock.

As time progresses, more and more of our beloved 80 series's components will be replaced with aftermarket components, if you have the $$, go with OEM until you can't... and if you don't, get what you can.

 

[Marvelicious]

I'm going to quote myself from a post I made a few weeks back as it seems fitting...

I ended up with a Nissens evaporator for the same reason as everyone else - DENSO is out of stock and with this economy, I don't have the coin for OEM when replacing everything at the same time - my original evaporator had rotted out and begun to leak (aluminum does corrode/rot over time and while your original evaporator seems to be in mostly-okay shape, will it outlast a fresh evaporator made out of the finest Chinese aluminum-like substance ). Having replaced it along with everything else, I have the coldest A/C I've had in memory. It fit fine and I'm not losing any sleep over it.
With that said, I'm tempted to chastise you for not buying a Denso condenser, which is in stock.

As time progresses, more and more of our beloved 80 series's components will be replaced with aftermarket components, if you have the $$, go with OEM until you can't... and if you don't, get what you can.

Since damage to metal is literally right in the middle of my professional wheelhouse, I have to quibble with your thoughts on aluminum. Aluminum certainly doesn't rot and while it can corrode, it's incredibly stable at a neutral pH. That's why I mentioned the rust belt earlier, though things like smog can also be a factor. The key is that something has to be happening chemically to break through that stable surface oxide layer. What I have heard described as "rotted" evaporators is undoubtedly corrosion from acidic or caustic condensation, not rot.

I spent some time today and soaked, washed and flushed approximately an entire douglas fir tree out of the fins, and the cleaner I get it, the better it looks. Pending a quick pressure test, I have zero concern about reusing the evaporator at this point. My 80 spent its whole life in the northwest, so no road salt in decades and usually not too much air pollution (the rain knocks it out of the air). I also don't have any noticeable corrosion on the lines, or really anyplace but the condenser, which again, looks like it was a junkyard part to start.

As for the new condenser, I get what you're saying about OEM parts, and in many cases I agree with you, but again... this is a truck with a salvage title and it's not meant for the concourse show. There are places where the OEM part is undoubtedly worth the extra cash, but I really think this will be fine. It looks well built and I honestly think that the Nissens condenser probably has increased cooling capacity. That's a lot more cross tube surface area vs a lot of fin area from the original.


Anyhow, I mostly started this thread to organize my thoughts. I've come up with a plan and I'm going with it at this point.

Thanks for the help, all.

 

[Gascan]

To clarify, I used the word “rot” figuratively speaking, not literally; I’m aware how metal breaks down. While I’m not a chemist, those evergreen needles and other debris are likely the chemical source of the changes in PH of water on your evap.

Lastly, I’ll add a data point to your thoughts on rust belt evap failures… I’m the 2nd owner of my 80 series. It has spent ALL of its life in the Portland, OR metro area & Florida, neither area is known to used salt in the winter time (I think that may have changed for the western portion of PNW after I left) my evap still corroded away.

 

[Marvelicious]

To clarify, I used the word “rot” figuratively speaking, not literally; I’m aware how metal breaks down. While I’m not a chemist, those evergreen needles and other debris are likely the chemical source of the changes in PH of water on your evap.

Lastly, I’ll add a data point to your thoughts on rust belt evap failures… I’m the 2nd owner of my 80 series. It has spent ALL of its life in the Portland, OR metro area & Florida, neither area is known to used salt in the winter time (I think that may have changed for the western portion of PNW after I left) my evap still corroded away.

I didn't think it was likely you meant rot literally, but it's a terrible term for what happens. Just a pet peeve.

Fair point on the needles, but honestly, this thing is fine. Despite the debris, there was very little tarnish, or residue where condensation drains to the bottom. It's possible that it is not original, the air box had definitely been apart before. I initially assumed it had been apart to be cleaned, but there's no way to know. The records I have are too spotty to be useful.

It's getting one of the prefilters that @Outsane sells, so debris should be less of an issue from here.

I can't remember exactly when they switched to a non-salt solution for spraying ivy roads out here, but my best guess is that it was some time in the 90s.

 

[Marvelicious]

Post script: Job done. It's July and I need a parka...