AC Evaporator Replacement

[gm79vette]

Hi! Does anyone have a procedure for replacing the AC evaporator when the
engine is still in the car? Thanks!

 

[TimAT]

You Sir, are about to learn some brand new bad words. But yes, it is possible, and really not that big of a deal. The box under the hood is split just for that reason. Find the bolts that hold the inboard half of the box to the firewall and the the outboard half, remove them and unplug everything. Split the box and it's right there. Not any fun at all. Be sure and use backup wrenches on the lines you're going to re-use. The aluminum is soft and the lines will twist.

 

[BankOfHell]

Make 3x sure you really need to replace it before you start. Get all new seals and sealant too.

 

[Bob Heine]

If it hasn't already been replaced recently, I would replace the heater core while you are in there. You should be able to pull the evaporator without having to remove the headers but you might find it easier if you remove the coolant overflow tank.

On a bright note, you are working with a small block. I replaced the evaporator and heater core on my big block and I was unable to speak by the time I finished it.

Once the headers have been removed and everything between the dash and firewall on the passenger side it's fairly easy.

You may find, as I did, that the housing has cracks and holes that weren't factory installed. A little fiberglass work, a coat or two of primer and you can test fit the housing. Probably best to do it once without the evaporator core so you know what it feels like when it goes back together.

My rocker arm covers weren't really in the way but once I sprayed the semigloss black I didn't want to scratch it up.

Compared to replacing the evaporator on my PT Cruiser, this was a pretty easy job.

 

[TimAT]

If it hasn't already been replaced recently, I would replace the heater core while you are in there. You should be able to pull the evaporator without having to remove the headers but you might find it easier if you remove the coolant overflow tank.

On a bright note, you are working with a small block. I replaced the evaporator and heater core on my big block and I was unable to speak by the time I finished it.

Once the headers have been removed and everything between the dash and firewall on the passenger side it's fairly easy.


You may find, as I did, that the housing has cracks and holes that weren't factory installed. A little fiberglass work, a coat or two of primer and you can test fit the housing. Probably best to do it once without the evaporator core so you know what it feels like when it goes back together.


My rocker arm covers weren't really in the way but once I sprayed the semigloss black I didn't want to scratch it up.

Compared to replacing the evaporator on my PT Cruiser, this was a pretty easy job.

That picture makes me just SOOOO happy I don't have A/C

 

[Bob Heine]

That picture makes me just SOOOO happy I don't have A/C

Tim, you're right -- I would gladly do without A/C if I didn't live in a sauna 300 days a year. Even up your way it's been warm lately. Our afternoon highs are in the low 90s but mornings starts at 80.

 

[BankOfHell]

Three years ago I replaced everything in my a/c system--correct to stock. It was just so so.

This year I did what I shoulda done in the first place--installed a Vintage Air system.

For once the car is cool and comfy to ride in on hot summer days.

Today was 101F in Raleigh--clearish skies. I have glass tops.

And you know what I did? I picked up an ice cream cake for my mom's birthday. And drove 20 minutes to her house. It was unmelted and yummy. No stock C3 factory a/c woulda passed that test. None.

Not to mention the wonderful extra room in the engine bay. No more crawling under the car for #6 & #8 spark plugs.

 

[stingray1977]

Hi, I am thinking of changing the evaporator in my 77 right hand drive it has the steering going through the box is this a big job with the steering the way it is. any suggestions Alan from down under Aus.

 

[gm79vette]

Hi, I am thinking of changing the evaporator in my 77 right hand drive it has the steering going through the box is this a big job with the steering the way it is. any suggestions Alan from down under Aus.

Hi,

I'm afraid I can't offer you much help at this point as I have not yet undertaken this part of the project. However, based on the comments I received about the difficulty of removing the evaporator, I would say having the "steering going through the box" is going to add some additional complications.