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A/C Evaporator

Jessica19699

Well-known member
Joined
Nov 3, 2014
Messages
132
Location
Stephens City Va
Corvette
1992 Bright Red Coupe
Hello CAC world can anyone tell me where the ac evap is located on a 92? I heard it was under the dash and was hard to get to Is this true or is it under the hood by the firewall?
 

Wayback

Well-known member
Joined
Aug 14, 2006
Messages
560
Location
S-NJ
Corvette
93 Ruby Aniv roadster/6spd
Under the dash,plenty on vid's on U-Tube to give ya a idea of the work involved.
 

Jessica19699

Well-known member
Joined
Nov 3, 2014
Messages
132
Location
Stephens City Va
Corvette
1992 Bright Red Coupe
Wayback, thanks for the reply I searched on you tube and I cant seem to find anything more than changing out the heater core hmm,i did see this posting on another corvette forum after searching the net for this issue, is there any truth to this it seems so cause this guy says he did it to his 92 coupe and that is exactly what I have, do you or anyone else have any insight on this copy/paste posting I'm sharing it shows this is under the hood, my issue is it seems like it isn't blowing enough air out of the vents. Thanks in advance

Here's how I did it on my 1992 LT1 Coupe:

1. Jack up the front of the car and removed the right front wheel
2. Remove the rear half of the fender well liner
3. Drain and remove the windshield washer reservoir, making sure to unplug the sensor
4. Unplug and remove the blower relay
5. Remove the cross brace that runs between the frame and firewall
6. Remove the blower assembly
7. Remove the heater hoses from the heater core, be prepared to lose a little coolant
8. Remove all the screws that attach the passenger side of the blower housing to the firewall
9. Remove the screws that hold the passenger half of the housing to the driver side half
10. Carefully split the housing at the evaporator split line, leave the monkey poopie in place
11. The air flow inlet side of the evaporator will be facing the passenger side
12. If it is like mine, it will be caked with an oily/tar dirt

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Close-up View ~ Yikes

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13. Gently remove as much of the bulk as possible
14. Line the bottom of the evaporator coil with rags
15. Spray disk brake cleaner into the evaporator coils to remove the oil and grease
16. Try to have access to an air compressor so that you can vaporize as much cleaner as possible

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17. The air flow outlet side of the evaporator will not be dirty. Don’t mess with it
18. Reverse the steps to re-assemble
19. Re-use the monkey poopie to seal the air around the evaporator inlet and outlet lines

Now ~ crank the A/C, put on some great tunes, and go for a cruise…..
 

Jessica19699

Well-known member
Joined
Nov 3, 2014
Messages
132
Location
Stephens City Va
Corvette
1992 Bright Red Coupe
Otter, thanks so much for posting this,this is perfect so it does look like the evap is under the hood instead of the dash and looking at the video it seems to go in synch with the posting I shared up above from a guy that did his evap on his 92, thanks again
 

Wayback

Well-known member
Joined
Aug 14, 2006
Messages
560
Location
S-NJ
Corvette
93 Ruby Aniv roadster/6spd
Jess,I apologize for the incorrect location.
 

Jessica19699

Well-known member
Joined
Nov 3, 2014
Messages
132
Location
Stephens City Va
Corvette
1992 Bright Red Coupe
So has a reply to this evap location is there anyway of checking to see if the evap is leaking with it being in cased like it is on the video above? I understand the dye technique which is already in my Freon when they converted it over from R12 but it seems to have a leak the mechanic found two leaks on the fitting they installed for the conversion kit so they tightened them and recharged the system and when I picked it up it worked great the car then sat for a few days and when I went to drive it today I noticed the a/c was no where near as cold as it was 3 days prior so it has to still have a leak somewhere I will take it back to the shop that fixed it before but i'm just wondering if there is anyway of seeing the dye if the leak is in the evap that is incased, the mech still insist the evap is under the dash I told him what was said here and the video I seen showing It under the hood and he still says he is pretty sure it located under the dash ,,this is becoming frustrating
 

LLC5

Well-known member
Joined
Sep 28, 2004
Messages
2,299
Location
Wa.
Corvette
98 black 6spd convert.
So has a reply to this evap location is there anyway of checking to see if the evap is leaking with it being in cased like it is on the video above? I understand the dye technique which is already in my Freon when they converted it over from R12 but it seems to have a leak the mechanic found two leaks on the fitting they installed for the conversion kit so they tightened them and recharged the system and when I picked it up it worked great the car then sat for a few days and when I went to drive it today I noticed the a/c was no where near as cold as it was 3 days prior so it has to still have a leak somewhere I will take it back to the shop that fixed it before but i'm just wondering if there is anyway of seeing the dye if the leak is in the evap that is incased, the mech still insist the evap is under the dash I told him what was said here and the video I seen showing It under the hood and he still says he is pretty sure it located under the dash ,,this is becoming frustrating



You should be able to see traces of the dye through the evaporator drain tube with a black light, or with Freon sniffer if there is a leak there. The system only working for 2-3 days sounds like a high side leak though, check the condenser very carefully with a black light (dye) for any unusual dirt/oil debris attached to it, if there is no dye then a strong bright led light will work. Check all the under hood fittings and hoses the same way.

I would have to see the vehicle to tell you where the evaporator is. The a/c tech should absolutely know where it is, or don't let him work on your vehicle again. It's a big unit and if it's under the hood there should be a big plastic/fiberglass unit bolted to the firewall on the passenger side that will make valve cover and spark plug access difficult.
 

Jessica19699

Well-known member
Joined
Nov 3, 2014
Messages
132
Location
Stephens City Va
Corvette
1992 Bright Red Coupe
You should be able to see traces of the dye through the evaporator drain tube with a black light, or with Freon sniffer if there is a leak there. The system only working for 2-3 days sounds like a high side leak though, check the condenser very carefully with a black light (dye) for any unusual dirt/oil debris attached to it, if there is no dye then a strong bright led light will work. Check all the under hood fittings and hoses the same way.

I would have to see the vehicle to tell you where the evaporator is. The a/c tech should absolutely know where it is, or don't let him work on your vehicle again. It's a big unit and if it's under the hood there should be a big plastic/fiberglass unit bolted to the firewall on the passenger side that will make valve cover and spark plug access difficult.

LLC5-Thanks for the reply there is a big black plastic unit bolted to the firewall of my car with A/C lines coming off it, take a look at the video attachment above that Otter shared mine looks exactly like that 91 that the guy in the video is working on. here is the link

YouTube
 
Last edited:

LLC5

Well-known member
Joined
Sep 28, 2004
Messages
2,299
Location
Wa.
Corvette
98 black 6spd convert.
LLC5-Thanks for the reply there is a big black plastic unit bolted to the firewall of my car with A/C lines coming off it, take a look at the video attachment above that Otter shared mine looks exactly like that 91 that the guy in the video is working on. here is the link

YouTube


That sounds like your evap.
 

LLC5

Well-known member
Joined
Sep 28, 2004
Messages
2,299
Location
Wa.
Corvette
98 black 6spd convert.
That's what I was thinking also thanks for the help



Before replacing the evaporator make sure that there are no leaks from the condenser, hoses, fittings or compressor. Common leaks are at the condenser and a/c compressor front seal.
 

Jessica19699

Well-known member
Joined
Nov 3, 2014
Messages
132
Location
Stephens City Va
Corvette
1992 Bright Red Coupe
Before replacing the evaporator make sure that there are no leaks from the condenser, hoses, fittings or compressor. Common leaks are at the condenser and a/c compressor front seal.


LLC5 yeah I took it back to the mechanic he told me the last leak was on the high side they had converted it from R12 to R134 the leak was by the fitting that is coming off the evaporator he is checking the condenser and all today or me.
 

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