Please answer any and all you have info of:

Was told by my mechanic that the Evaporator is where the leak is on my sons 98 Cherokee. He knows that we work on the car and said it would not make sense to pay him to replace it, that it is time consuming but we should be able to do it. I have a couple questions.

• What is the tool I need to separate the AC lines that come through the firewall? I haven't been able to locate them.
• The Evaporator at Jeep Air is $100 I see the
  same part on Amazon
  same part on Amazon
  for $42, any reason not to go with the Amazon one, same for the drier?
• Do I need to buy an o ring kit? Or should that come with the parts?
• Any reason I should not rent the AC charging tools and oil/charge it myself?

Thanks for any tips / tricks.

 

You'll need a vacuum pump to evacuate the air/moisture from the system prior to adding the "freon". You may be able to rent one, but the "mechanical" ones require a fair bit of CFM from your air compressor...

 

I had to replace the heater core on my 98 last fall. Sounds like you are comfortable taking your jeep apart. This isn't too hard of a job, just on the long side to get everything apart. This is my thread.. Before you start, take it ot a shop to evacuate the r-134. For the AC lines, you'll need a quick disconnect set like . I got a set from harbor freight. They have the metal set and a plastic set. Be warned, the AC lines can be tough to get separated since they have most likely been connected for 20+ years. I spray a lot of WD-40 in the joint and then try to twist and push/pull at the same time. If a connection won't come free, keep twisting and push/pull and it will eventually come out. You can get a complete o-ring/seal kit from https://www.rockauto.com/en/catalog/jeep,1998,cherokee,4.0l+l6,1315943,heat+&+air+conditioning,a/c+system+o-rings+/+seals,13290 pretty cheap.
I purchased a and AC gauge set. They have both come in handy and pay for them selves in 1 use vs taking to a shop (time and $$). Plus, I have 4 vehicles I have used them on at various times. I bought a robinair gauge set off of ebay. As far as the evap core, when I see the same part with a vastly different price at different vendors, In this case, looks like it's 1 year across the board on that part.
When I did my heater core, it was 2 days. I could have done it in 1 long day, but it was late November so ran out of light and my back needed a break.

 

I have a pancake compressor. would you say I need to take it to the shop for that part? I would much rather be able to test for leaks at home.

 

Thanks for the reply. Can you tell me which o ring set i should get? Also, Do I need to buy the foam seal kit somewhere? Or will the box holding the cores go back together? Can I use general insulating tape or do i need a specific set?

 

One model I see on Amazon requires 4.5 cfm @ ~90 psi for a half hour or so to prep it for filling.. To check for leaks, you wouldn't need to go to that extreme, but it's still going to take a fair amount of runtime on the compressor to get to a good vacuum level.

 

Before I got a 2 stage vacuum pump, I used on of these used with a compressor. I was able to get it ~-28 inches, but I had to do a lot of compressor cycling. Run until the compressor kicked on, turn the flow off, repeat many times.

For the oring kit, I think I got the four seasons one, but all 3 shown there should be the same. I have done the AC system on my 98 and 99 and the orings all looked pretty good, but for the cost it's so much easier to replace them. Make sure you lubricate them with some PAG oil.

this si the part # for the heater box gasket: 4874069AB. I needed to replace mine since I was getting some leaking around that seal prior to the R&R. I'm sure you could find a way to reuse the old one or make them from a foam sheet. I just didn't want to mess with it and not have to go back in. I bought it from here. In my notes from last year, I had the proce at $58. Looks like the foam must have some gold leaf or titanium in it since it has gone up $13 since then.

>Or will the box holding the cores go back together? Can I use general insulating tape or do i need a specific set?
I purchased some foam weatherstripping at Homedepot for the internal support around the heater core. I don't recall about the AC evap core, but I probably used the same as on the heater core. Most likely some 1 or 2 inch foam from HomeDepot.