When I bought my XJ about 4 years ago it had a slow leak leak in the evaporator (confirmed with electronic detector). Topping up each spring kept the AC going for the rest of the season. I knew at some point this would become a larger leak and the day has come - suddenly there is fast compressor cycling and little cooling way ahead of schedule. After running the AC for a few seconds I don't even need to hold my detector's sensor under the dash, it squeals like crazy as soon as it's switched on inside the cabin. So time to bite the bullet. Of course I'll be replacing the heater core as well while in there.

What are the current best aftermarket evaporator and heater core in terms of fitting with the least amount of aggravation? (It's going to be aggravating enough pulling the dashboard out without having to struggle to fit parts that aren't quite right.) Four Seasons has typically been my go-to brand for HVAC parts, but if anyone here has recently replaced these parts I'd like to hear what you used and how well they fit.

I don't know if I'll have time to get to this job before the end of the summer, if not I'll take it up in the spring. (The Jeep is not a daily driver so I can live without the AC for a while.)

 

They're all probably cheap chinese knock offs with different labels anyway..........

 

I bought a heater core from Quadratec, their best one, aluminum, and it's pretty much the same fit except on the edges ..the non-tank edges of the heater core, the sides aren't completely smooth like the factory one. A small amt of high-temp foam ..the black stuff, would take care of that. Some people commented that there are fewer fins, and that's true, but the passages appear slightly larger so the amt of coolant which can flow through them seems greater and therefore should have about the same BTU capacity.

Ultimately I didn't use the quadratec one, I went with a new copper heater core. It has a lot more surface area and quality was A1! But it's thicker and the ends are different and won't fit in the original foam gasketing. Since my jeep is used for plowing snow I wanted as much heat as possible. It came with a thick strip of 1/2" dense self-adhesive foam for the gasket and I just used that, it worked fine. Throws heat like a mother. The other benefit of copper is it has a wide pH range compared to aluminum. But I wouldn't have any problems using the Quadratec one, that was my original intention (I still have it sitting downstairs). I can't remember who supplies it to Q/T. I think it was like $80 but on sale for $65 or something like that.

Overall the job is not that difficult. It's not as difficult as some say, I guess it depends on your mechanical experience too. I would spray the bolts down with penetrating fluid that protrude through the firewall. Do that now a few times b/c getting them out with ease will make your job easier. What made my job suck is I did it outside in freezing temps or temps in the teens!! I didn't want to leave my Trans Am sitting out in the snow for a couple days. You're smart to do it now.

Once you get it apart, look at all the seals. By now, a lot of jeeps the foam on a couple doors has become brittle and rotted. On mine it was like one day the door between the outside air and inside air just gave out. Then, you just can't keep it warm. I replaced all of mine, other than the main door that diverts AC and heater core air to regulate the temp ...that one is a much higher quality foam and was still very good on my 87.

Replace your coolant with new and use filtered water (I'm sure you knew that, but just saying..). Coolant pH can change over yrs. Put some long-life stuff in it. On mine, I tweaked it to a pH of 9.2. The right pH is really critical when mixing metals: copper, iron and aluminum. They prefer different ranges and there's a small window where they all overlap and feel 'happy' (meaning, the pH won't attack them). Water and coolant attacking metals is normal ..but coolant helps slow it down, and they make AL parts thick enough that they last a long time in normal envrionment. But a heater core has paper-thin metal for good heat transfer. If your pH is off, it'll attack it and make swiss cheese out of it pretty quick. Guys don't know it was the pH that attacked it ...they just blame the heater core as being junk. Copper has a much wider range and works better with iron, that's why they traditionally used copper. Easier to maintain.

You can buy a cheap pH tester on ebay. I worked in the industrial heating/cooling for years and I've seen lots of guys ruin expensive equipment by running the wrong pH and scavanging their equipment. Same holds true with heater cores. I suspect most of the guys who cry-baby about their AL heater cores crapping out in a couple years were way out of the pH range. By adding a bit of Sodium Hydroxide (drain cleaner -- just a pinch) can move ya higher ....a touch of lemon juice (or sulfuric acid) can back ya down if ya go too far. Generally just adding new coolant and purified water doesn't get a vehicle withing the 'happy range' ...a touch of NaOH will. This is the tester I have (you should get all 3 power packs. the powder packs you mix with water to get a 'known' pH and use it to calibrate (and verify) the tester. 2x packs will get you to a tenth, 3x will get you to within a onehundredth of pH). Mine has kept and held it's pH. I keep my pH water mixes in tupperware containers to periodically check. I have a boiler in a house too, so I check the water for that too. A great tool for the $$ (Thank you Chinese ...for making and selling a brilliant tool that doesn't cost $100!!).
https://www.ebay.com/itm/Digital-Ph-...ffc295cac9bcd1

I can't comment on the ac evap core. I didn't replace mine. If yours is R12, now's the time to consider a 134 swap-over with the right core.

Good luck.

 

Should have mentioned it's a '99 XJ, though that does appear on the sidebar with my info.

I'd definitely be interested in a copper heater core. Main use of this Jeep is for when we get deep snow, so a good heater is a plus. Although it's not exactly New England here it's not uncommon for us to get a foot or more of snow in a good storm as well as temperatures that approach or reach single digits. Will have to check around for availability and pricing on a copper heater core.

BTW, I always use distilled water for cooling systems. I figure it's cheap insurance. That inexpensive pH tester looks like a good thing to have as well.

 

So far the only copper heater core I've been able to find is this, and it's listed as out of stock:

https://www.superiorcooling.co/48740...-wrangler.html

I don't know whether that means the part is just temporarily out of stock, or permanently discontinued. (Will need to contact them.)

 

That copper heater core is listed as in stock now. Doing some poking around it turns out these are locally manufactured in Texas, USA, and are made up in batches several months apart. Kind of pricey but I'm probably going to order one rather than go with a China-made aluminum core. Though starting an order I see shipping is over $36! Still if I want good heat in the winter it's probably going to be the best bet but will wait until I know I'm ready to do the job.