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Discussion Starter · #1 ·
May this thread be a living testimony to the jerk head who designed our AC/Heater box.
It's over 110F here and I have no AC due to leaking Evaporator.
And in this weather I have to do this myself due to labor costs .
After 6 hours into the job got this out

Tire Wheel Light Automotive tire Black


Which is buried inside here

Tire Automotive tire Motor vehicle Wheel Automotive design


Which is buried under the dash here.

Car Motor vehicle Hood Vehicle Automotive design


Not sure how long it will take it put everything back together.
Good luck everyone who have to deal with heater core/AC Evaporator.

So basically, below is the "how to" for this job
01) Seat yourself in the car and start remove everything on the way until the AC box is loose.
02) Get the black box out.
03) Remove all bolts.
04) Replace the defected parts.
05) Reverse the above.
 

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Wow, I had a 1996 Maxima and had it out in 30 minutes and back in in 15 minutes. Easiest vehicle to work on of any car I have owned. Now I know what to look forward to in due time.
 

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When I was going to do my heater core myself - same process - I took enough parts out to see that large crossmember across the dash. Fearing I wouldn't be able to get it out and back in by myself, its one of the few jobs I have taken to the shop in the last 2 decades.

Did you find the cross member difficult - it looked pretty heavy? Of did you just remove then replace - a bunch of parts in and out?
 

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2005 Xterra 4wd 6MT 1.5" lift Heftyfab skids,Shrockworks diff guard,Hardcoreoffroad sliders
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I have done the heater core in my X it was the biggest PITA I have had to do swapping the motor out was easier.
 

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If I had just spent 1.5 to 2 days tearing apart and reinstalling everything on my Xterra for a heater core replacement I would be griping about the design also.

I can remember the days when heater cores were mounted under the hood on the firewall.
 

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Discussion Starter · #8 · (Edited)
Not everything can be immediately accessible, or replaced in under an hour. How does that make the design engineer a jerk? Properly maintain your cooling system and this likely wouldn't happen.
X is maintained well. This is a leaking AC Evaporator core. It's end of its service life. In the desert heat we have low life on AC parts.

The main PITA here is the removal of the metal dash support. Literally everything has to be taken apart.
On the driver side there is removable bracket on the metal dash support to ease steering column removal or to access bolts beneath.
They could have done something similar on the passenger side and gave access to evaporator and heater core.

Burying the AC parts this deep is like burying the radiator near the firewall under the hood and you have to take apart everything in the engine bay to replace it.

When I was going to do my heater core myself - same process - I took enough parts out to see that large crossmember across the dash. Fearing I wouldn't be able to get it out and back in by myself, its one of the few jobs I have taken to the shop in the last 2 decades.

Did you find the cross member difficult - it looked pretty heavy? Of did you just remove then replace - a bunch of parts in and out?
You can take the box your self out. Cross member is not that heavy. When assembling you need another person to help align stuff. Everything together is bit heavy to maneuver yourself.
The black air box has to come out of the vehicle. There are 5.5mm bolts on the plastic support facing firewall that has to come out to remove heater core. For Evaporator core you have to take apart the black box. There are 20 or 30 bolts holding it.
 

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If I had just spent 1.5 to 2 days tearing apart and reinstalling everything on my Xterra for a heater core replacement I would be griping about the design also.

I can remember the days when heater cores were mounted under the hood on the firewall.
Its actually not just Nissan. My Jeep GC was actually worse - seats, steering wheel, center console - everything had to come out. Needless to say I bypassed the heater core and it became a summer only vehicle for the remaining time I owned it. Luckily I live in South Carolina so summer is about 9 months.
 

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That is a mess, scared me to see it. My 84' 300ZX you had to remove the entire dash, I had a shop do it, thankfully or unthankfully the shop had to essentially do every 84-89 300ZX at some point sa they all leaked coolant into the passenger foot well so while it was a complex repair they did a million of them.
 

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Welcome to my world! People wonder why I HATE modern vehicles. Here's a prime example. They're all loaded with ******* engineering exactly like this. I've wasted YEARS of my life dealing with engineering like this.

Back in the day, you never saw evaporator cores corrode to nothing like that. The cost cutting is another huge pet peeve of mine. EVERYTHING is low-bidder junk these days. So infuriating! I put a new evaporator in my '86 Grand Marquis in 2015, only because it was plugged with 30 years of tree crap and dirt. My reasoning was with a whole new system, I wanted maximum cooling. The core was still good otherwise! I could steam clean it and reuse it some day.

The job took me less than 2 hours start to finish. Remove the inner fender liner, disconnect the lines, and unbolt the plastic housing from the firewall. DONE!

Automotive parking light Typewriter Automotive tire Automotive lighting Vehicle


Automotive tire Wood Tread Gas Automotive wheel system


Vehicle Automotive tire Motor vehicle Hood Automotive lighting


Motor vehicle Auto part Electrical wiring Gas Automotive fuel system
 

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Discussion Starter · #12 ·
This has turned into a nightmare!!. I put everything back together and filled the refringent.
It was fine for 3 days. Today AC cooling is very low and there is smell form the vents. I think it's leaking again
 

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Best way to find leaks is with a sniffer. Might be worth a few bucks to pay a shop to at least find the leak for you with their refrigerant detector (sniffer). Will save you tons of headaches.

Another trick I use to keep leaks from happening is, I put Nylog on every single o-ring. It has the nickname "liquid snot" in the industry, since it's thick, and sticky. The stuff is amazing. You'll never have an o-ring leak using that stuff. There are different types of Nylog, so you want the "blue" labeled stuff. At the very least, you want to lubricate the o-rings with refrigerant oil.

Crap - just went to look up a link to the Nylog, and it looks like it's discontinued. DAMMIT. Figures, too, since the stuff actually WORKS. RT201B - Refrigeration Technologies RT201B - Nylog Blue Gasket & Thread Sealant

Another backyard way of finding leaks will cost you some refrigerant, and possibly another accumulator depending on how humid it is outside. You can use compressed air to pressurize the system, then use soapy water in a spray bottle to hose down the condenser, evaporator (if you can access it), and any and all connections. Keep in mind if you do this, you'll need to pull a vacuum on the system for at LEAST 1 hour before recharging with refrigerant after repairs. Compressed air will introduce moisture you don't want in the system. Vacuuming will boil the moisture out of there. The longer the pump is left on, the better.
 

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Best way to find leaks is with a sniffer. Might be worth a few bucks to pay a shop to at least find the leak for you with their refrigerant detector (sniffer). Will save you tons of headaches.

Another trick I use to keep leaks from happening is, I put Nylog on every single o-ring. It has the nickname "liquid snot" in the industry, since it's thick, and sticky. The stuff is amazing. You'll never have an o-ring leak using that stuff. There are different types of Nylog, so you want the "blue" labeled stuff. At the very least, you want to lubricate the o-rings with refrigerant oil.

Crap - just went to look up a link to the Nylog, and it looks like it's discontinued. DAMMIT. Figures, too, since the stuff actually WORKS. RT201B - Refrigeration Technologies RT201B - Nylog Blue Gasket & Thread Sealant

Another backyard way of finding leaks will cost you some refrigerant, and possibly another accumulator depending on how humid it is outside. You can use compressed air to pressurize the system, then use soapy water in a spray bottle to hose down the condenser, evaporator (if you can access it), and any and all connections. Keep in mind if you do this, you'll need to pull a vacuum on the system for at LEAST 1 hour before recharging with refrigerant after repairs. Compressed air will introduce moisture you don't want in the system. Vacuuming will boil the moisture out of there. The longer the pump is left on, the better.
Looks like you can still buy the 2 pack of it per your link.
 

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This has turned into a nightmare!!. I put everything back together and filled the refringent.
It was fine for 3 days. Today AC cooling is very low and there is smell form the vents. I think it's leaking again
Is the compressor cycling off and on, or just staying on, or staying off?
Does the temperature change when you move it from low to high heat with the ac on?
Did you replace the heater core while it was apart?
Check for coolant leaks on the passenger floor.
Check coolant level in the reservoir.

Did the expansion valve go on without an issue?
.
 

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Discussion Starter · #17 ·
Is the compressor cycling off and on, or just staying on, or staying off?
Does the temperature change when you move it from low to high heat with the ac on?
Did you replace the heater core while it was apart?
Check for coolant leaks on the passenger floor.
Check coolant level in the reservoir.

Did the expansion valve go on without an issue?
.
Compressor is working fine.
Yes the temp changes from cold to heat with the knob
No I didint replace the heater core. In case of heatercore leak in future I will bypass it since we never use it.
No coolant leaks in passenger floor or resorvoir.

I replaced the expansion valve with after market one. it was exact match to the oem,
But I hear whistling noise occasionally from the valve.
Also the Evap core itself was also aftermarket. It was 1/2 inch shorter than the OEM. Whenever I hit pothole there is sudden burst of smell from the vents.
.
 

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Discussion Starter · #18 ·
Compressor is working fine.
Yes the temp changes from cold to heat with the knob
No I didint replace the heater core. In case of heatercore leak in future I will bypass it since we never use it.
No coolant leaks in passenger floor or resorvoir.

I replaced the expansion valve with after market one. it was exact match to the oem,
But I hear whistling noise occasionally from the valve.
Also the Evap core itself was also aftermarket. It was 1/2 inch shorter than the OEM. Whenever I hit pothole there is sudden burst of smell from the vents.
 

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Whenever I hit pothole there is sudden burst of smell from the vents.

Today AC cooling is very low and there is smell form the vents. I think it's leaking again.

Compressor is working fine.
If it's leaking, the compressor will soon start cycling and then stop. You can't have low refrigerant and have a compressor working fine.

What do you think that fragrance is ? Coolant? Refrigerant?
I've never known refrigerant to leak sporadically... it either leaks or it doesn't leak.
That being said, if that is indeed refrigerant you smell, the only possible scenario I can think of is a loose expansion valve.

How much 134a did you put in? Two 12-oz cans fill it to capacity.
 

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Wouldn't shock me one bit to find a bad new expansion valve. And also one that doesn't seal up correctly, even when tight. I'd be looking at that.

Feel the lines when you lose cooling - if the low side is still cool with a little condensation on it (Depending on your climate - this won't happen in SoCal or Phoenix) going back to the compressor, it's working, and you've probably got a blend door issue.
 
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