heater core/ evaporator replacement tips?

[Farrar]

Hey, has any of y'all replaced your heater core and evaporator? If so, how long did it take and are there any special tools required? Any other advice? It looks like I will be doing this job sometime this summer.

Thanks,
Farrar

[Nicholas R]

Replaced my evaporator core back in 2007 with Hervey's reproduction. Unfortunately my system started leaking and its leaking again from the core itself :swear1: Looks like I'm doing the exact same job again. What a nightmare. It's a rough job, one I hoped to NEVER have to do again.

The real question now is whether or not to give Hervey's evaporator another chance or go with a different one.

[Farrar]

So I am guessing I should budget an entire weekend to do this job?

Are any special tools required?

Farrar

[A Van]

So I am guessing I should budget an entire weekend to do this job?

Are any special tools required?

Farrar

Easily, you need to account for the "unknowns"

None that I remember

[stevedmc]

I have replaced my dash, so you could say I am experienced with that part of the work.

[Farrar]

I have replaced my dash, so you could say I am experienced with that part of the work.

How long did that take?

Farrar

[stevedmc]

How long did that take?

Farrar

I believe it took me a whole weekend to do the work. This was the first job I ever did on the Delorean myself and I didn't know much about working on the car and was afraid of screwing up.

Now that I have better tools and know the car better I believe I could remove and replace the dash in less than 4 hours.

[Farrar]

afraid of screwing up.

That's me all the time! :lol:

Thanks -- I will plan to spend a weekend, then, replacing the heater core and evaporator.

See you Saturday!

Farrar

[kings1527]

That's me all the time! :lol:

Thanks -- I will plan to spend a weekend, then, replacing the heater core and evaporator.

See you Saturday!

Farrar


Hi Farrar,

Just a quick question on this. Can you replace the evaporator by itself or if I want to replace the evaporator, do I have to remove the heater core, too?

[sdg3205]

They are in the same box. They will come out as a unit so to speak.

The box will split open along the horizontal axis to give access to both.

It's a truly time intensive job but worth it.

[dmc4087]

I just completed this job. I wouldnt say its difficult, just time consuming removing bits of interior.

Make sure you note where the vac pipes go to on the box itself.

[kings1527]

They are in the same box. They will come out as a unit so to speak.

The box will split open along the horizontal axis to give access to both.

It's a truly time intensive job but worth it.


I just completed this job. I wouldnt say its difficult, just time consuming removing bits of interior.

Make sure you note where the vac pipes go to on the box itself.

Thanks for the responses, guys. I'm researching this so I have all the info ahead of time. Stupid question time: so since they come out as a unit, that definitely means that I'll have to drain all of the coolant and disconnect both the heater core and evaporator, even if I just wanted to get the evaporator out?

If that's the case, I might just put in a new heater core even though mine's working fine right now.

[Farrar]

I didn't drain all of the coolant. In fact I didn't drain any. Instead, I placed papertowels and a bucket under the car to catch the coolant I knew I'd lose removing the heater core.

Also, remove the carpet on the passenger side because you may spill out some coolant from the heater core as you twist the box to remove it.

[Nicholas R]

They are in the same box. They will come out as a unit so to speak.

The box will split open along the horizontal axis to give access to both.

It's a truly time intensive job but worth it.


Thanks for the responses, guys. I'm researching this so I have all the info ahead of time. Stupid question time: so since they come out as a unit, that definitely means that I'll have to drain all of the coolant and disconnect both the heater core and evaporator, even if I just wanted to get the evaporator out?

If that's the case, I might just put in a new heater core even though mine's working fine right now.

This is not true. They do not both have to come out at the same time. I've replaced the evaporator core twice now in my car and have never replaced the heater core. Never even gone near it. I just remove the evaporator core section of the HVAC box under the dash. Dont even touch the heater area. There is a horizontal split in the box, but there is also a vertical split that separates the evaporator section from the rest of the box.

To do the evaporator, this is the only section of the box that has to be removed:
17767


Likewise I know several others that have replaced heater cores without doing anything in the evaporator area.

[kings1527]

This is not true. They do not both have to come out at the same time. I've replaced the evaporator core twice now in my car and have never replaced the heater core. Never even gone near it. I just remove the evaporator core section of the HVAC box under the dash. Dont even touch the heater area. There is a horizontal split in the box, but there is also a vertical split that separates the evaporator section from the rest of the box.

To do the evaporator, this is the only section of the box that has to be removed:
17767


Likewise I know several others that have replaced heater cores without doing anything in the evaporator area.

Outstanding, Nick. That's what I needed to know. Thanks!

[Farrar]

Nick, how were you able to remove the screws at the rear of the box? I had to remove the unit to get its three pieces apart. And sealing it back up with press-n-seal ... are you magical or am I an idiot?

[DMCMW Dave]

Nick, how were you able to remove the screws at the rear of the box? I had to remove the unit to get its three pieces apart. And sealing it back up with press-n-seal ... are you magical or am I an idiot?

Removing the screws is hard. Getting them back in is darn near impossible. I've seen the aftermath of a few of these partial-removal jobs and screws are always missing. Nick must have tiny hands.

[kings1527]

Removing the screws is hard. Getting them back in is darn near impossible. I've seen the aftermath of a few of these partial-removal jobs and screws are always missing. Nick must have tiny hands.

So unless I have raccoon hands, really the only way to get the screws back in place in the rear is to remove the entire assembly? And that means removing the heater core and evaporator as a unit? Trying to get a visual of all this.

[Nicholas R]

Thanks for the responses, guys. I'm researching this so I have all the info ahead of time. Stupid question time: so since they come out as a unit, that definitely means that I'll have to drain all of the coolant and disconnect both the heater core and evaporator, even if I just wanted to get the evaporator out?

If that's the case, I might just put in a new heater core even though mine's working fine right now.


Nick, how were you able to remove the screws at the rear of the box? I had to remove the unit to get its three pieces apart. And sealing it back up with press-n-seal ... are you magical or am I an idiot?


Removing the screws is hard. Getting them back in is darn near impossible. I've seen the aftermath of a few of these partial-removal jobs and screws are always missing. Nick must have tiny hands.

I got all mine out and back in both times. Oh yea, it's a major pain in the ass but still dooable. I have probably close to a dozen different quarter inch drive extensions in different lengths, some of which are wobble extensions, that I used on both replacements. To get the ones on the vertical split, I always had to go from the driver side with several long extensions. Sometimes I would have a friend guide the socket onto the bolt for me for remove. Same thing for installation. Any time I ever had to install a screw, I would take a tiny piece of paper towel, put it between the socket and the screw and press the screw into the socket, with the piece of paper towel sandwiched between the two. It created enough friction to hold the screw into the socket so it could be guided to the hole.

To get the ones in the back was mostly by feel. I used the above photo as a guide so I knew where all the bolts I was looking for were. First I would try to get a finger on one just so I had and idea where it was, then send the socket up on an extension or two, moving it until I could feel it settle on the screw head. A lot of work was done while upside down under the dash. I also tried using a mirror to see what I was doing (which worked ok).

For sealing I put silicone between the two halves before pressing them together.

I'm trying to remember exactly the course of events. I know after the last time I wrote it down because there was only one way things would go in. I posted it somewhere on here but have no idea where. If I recall correctly, I would drop the lower half of the evaporator box with the evaporator inside (fan already removed), down but it couldn't be removed because of the angles. I think the upper half of the box had to be removed next, then the lower half and evaporator could be removed together.

For re-installation I think it was just reversed. Install the lower half of the box with the evaporator set in the box (getting the aluminum hoses through the firewall) but still leave the whole assembly kind of hanging there in the footwell area (none of the box bolts in), then install the upper half of the box, then bolt up the lower half of the box.

I cant promise 100% but I'm pretty sure this is what it was. Both evaporator replacements were so full of anger and frustration that the memories are kind of blurs, haha. This all may make it sound easy, but it's not. There are few jobs I wouldn't rather do than an evaporator. Give me a fuel accumulator over an evaporator any day! :biggrin:

[TripleZeroFilms]

I'm getting ready to undertake this job myself, and will be attempting to remove the evap without removing the heater side. That being said, can anyone tell me how many vertical and how many horizontal screws will need to be removed? At the moment, by feel, it seems like 4 horizontal screws connecting the sides together and 10/11 vertical screws holding the top of the box to the bottom. Can anyone who has done this before verify/correct these numbers?

[Farrar]

I'm getting ready to undertake this job myself, and will be attempting to remove the evap without removing the heater side. That being said, can anyone tell me how many vertical and how many horizontal screws will need to be removed? At the moment, by feel, it seems like 4 horizontal screws connecting the sides together and 10/11 vertical screws holding the top of the box to the bottom. Can anyone who has done this before verify/correct these numbers?

I can't give you the number off the top of my head, but I do know that the Workshop Manual (which I don't have with me right now) says "remove ___ screws." So I kept fondling around in the dark finding more until I found that number, and it came out. So I'd say the Workshop Manual is correct.

Good luck, and post if you get stuck - I'll try to help you as best as I can from my fuzzy memory. :)

[TripleZeroFilms]

I can't give you the number off the top of my head, but I do know that the Workshop Manual (which I don't have with me right now) says "remove ___ screws." So I kept fondling around in the dark finding more until I found that number, and it came out. So I'd say the Workshop Manual is correct.

Good luck, and post if you get stuck - I'll try to help you as best as I can from my fuzzy memory. :)

I will definitely take you up on that should the need arise.

I am surprised, however, that the manual would speak on removing just the evaporator side of the heater box assembly. From what I've gleaned off the net, that sort of removal is a bit less traditional. I'll have to give it a look when I get home and see.

[Farrar]

I am surprised, however, that the manual would speak on removing just the evaporator side of the heater box assembly.

It doesn't, but I think removing all of the screws would make sure that you have the wiggle room to separate the top and bottom pieces on the right side. That's just my opinion.