Replacing Evaporator core...i think

[Harmon]

i am on year 2 of trying figure out my AC issue....I have a leak somwhere...the only thing I have not changed is the Evaporartor core.  I was wanting to know if anyone out there had an issue with it leakin?  And if so, is it a big job?

 I just am at my wits end, and would love to drive my 86 chevy with the windows up and cold air blowing.
Thanks

[zieg85]

Did you have the dye put in the system? 

[Mr Diesel]

I haven't had to replace one yet on these trucks, but it should be pretty easy. Just unbolt the plastic cover under the hood and lift it out. (disconnect hoses and stuff too, of course). I did the one on my 1985 Camaro. It was pretty easy, and there was a lot less room to work under that hood than these trucks.

[78 Chevyrado]

Buy a GM evap core if you can find one....   I used brand x (don't remember which one)  and it took extensive reworking of both the pipes on the core and the link pipes I had that came with the truck.  had to bend all into almost totally different shapes.  But it worked and hasnt given me a problem since


Like above, put dye in your system, refill it then look for the leak.  it should be messy looking.  only thing with the dye is, you WILL NEED a black light to find it.  This is the simplest way to find a leak.

Good luck!

[Harmon]

Ive done the dye and had a link at where the orifice tube goes and those two pipes connect....Now I replaced the hose and the orifice tube is so far up the hose toward the evap core that I cannot get it out....perplexing.

[Captkaos]

How far up is it?  if it isn't to very far, you can run a sheet metal screw up in there and pull it out.

[78 Chevyrado]

How far up is it?  if it isn't to very far, you can run a sheet metal screw up in there and pull it out.

If that doesn't work, you can get a new evap core, of cut off the line the orifice tube is in and put in an available extender to put back what you cut off of the tube.

Orifice tubes can be horrible to get out.  one time on my 78, the old orifice tube slipped right out with my fingers, none others have come out in one piece yet.

If you do have dye and cannot find a leak, it may be the evap core which is hidden from site may be leaking.  put dye in, and wash and clean every part of the AC system, so it's clean looking and free of dirt, ESPECIALLY any connections.  then wait for it to leak.  there will be dye there.  without a black light it will look bright green-tinted.  a black light in the dark makes it 90% easier to find leaks.  IF the orifice tube is ruined, it may be blocking flow so the dye cannot disperse through the system like it should.  since you are having problems with the oricife tube that should be your number one priority.  that basically controls the whole system.  if it's bad, nothing else will work right.