HVAC replacement parts

E28 technical advice asked and given! Troubleshooting, modifications and more.
Dale3783
Posts: 424
Joined: Oct 26, 2016 10:01 PM
Location: Miami, FL

HVAC replacement parts

Post by Dale3783 »

So after buying and installing Austin's AC kit, my AC system is cool, not cold. So I'm about to dive into the job of pulling the HVAC box out from under the dash to replace the evaporator and expansion valve. I'm going to clean everything and replace all the foam insulation as I've seen many others do in different threads over the years.

What else are must do's once I'm in there? I'm going to replace the AC blower motor, heater core and the evaporator and expansion valve as mentioned above, but what else?

Anything else to look for while I'm in there?

Thanks
Federico
Posts: 428
Joined: Sep 16, 2013 6:38 PM
Location: Argentina / California

Re: HVAC replacement parts

Post by Federico »

Not much more to add.
Be nice to your bowden cables. Disconnect them from the levers and leave them alone. They can become very stiff if you bend them just slightly.
vinceg101
Posts: 4483
Joined: Jun 20, 2007 2:40 AM
Location: Los Angeles, CA

Re: HVAC replacement parts

Post by vinceg101 »

Just went through this whole exercise recently. Sounds like you've got everything covered.
Dale3783
Posts: 424
Joined: Oct 26, 2016 10:01 PM
Location: Miami, FL

Re: HVAC replacement parts

Post by Dale3783 »

So no other sensors or electronic parts inside or around the box? Thanks guys

Specifically, if my compressor is coming on, do I need the evaporator temp control module or the temp sensor that goes into the AC box?
demetk
Posts: 8427
Joined: Aug 09, 2007 8:58 AM
Location: CT, USA

Re: HVAC replacement parts

Post by demetk »

As long as the evaporator is leak free why do you need to change it?

I'm assuming you flushed the the whole system? If so did you flush the evaporator with the txv valve (Thermostatic expansion valve) in place?

Did you charge with r134a?
Dale3783
Posts: 424
Joined: Oct 26, 2016 10:01 PM
Location: Miami, FL

Re: HVAC replacement parts

Post by Dale3783 »

The reason I’m pulling it apart is to replace the expansion valve. I was going to replace the evaporator core just because I’m already in there.

The system was flushed before being filled after I installed AC Solutions kit to convert it to R134a. Everything under the hood is new, compressor, condenser, lines, filter dryer but the air still wasn’t cold. Just kinda cool, which doesn’t cut it here in Miami.
demetk
Posts: 8427
Joined: Aug 09, 2007 8:58 AM
Location: CT, USA

Re: HVAC replacement parts

Post by demetk »

Before you take it apart get some measurements for us. With car at idle, ac on and the aux fan running.

1. Vent temp with blower speed on 1. A multimeter with a temp probe is ideal but you can also use an electronic meat thermometer with a probe.
2. High side pressure
3. Low side pressure
4. For subcooling calculation, temp of the high pressure line as close to the condenser as possible. A good place is just before the filter drier. Tape the temp probe onto the line and insulate it. The temp will allow you to calculate the subcooling and will determine if you're charged right, undercharged or overcharged.
gwb72tii
Posts: 229
Joined: Sep 21, 2021 4:58 PM
Location: Washington state

Re: HVAC replacement parts

Post by gwb72tii »

I'd be curious as to which evaporator core you use, oem or something from rock auto or equivalent?

anyone have experience with the rock auto knock off?
Dale3783
Posts: 424
Joined: Oct 26, 2016 10:01 PM
Location: Miami, FL

Re: HVAC replacement parts

Post by Dale3783 »

demetk wrote: Jan 08, 2022 6:12 PM Before you take it apart get some measurements for us. With car at idle, ac on and the aux fan running.

Ugh. Too late. I got everything ripped apart yesterday.
demetk
Posts: 8427
Joined: Aug 09, 2007 8:58 AM
Location: CT, USA

Re: HVAC replacement parts

Post by demetk »

Dale3783 wrote: Jan 09, 2022 8:22 AM
demetk wrote: Jan 08, 2022 6:12 PM Before you take it apart get some measurements for us. With car at idle, ac on and the aux fan running.

Ugh. Too late. I got everything ripped apart yesterday.
np. Post your measurements when you have everything back together.
Ju@n
Posts: 585
Joined: Apr 27, 2013 1:11 PM
Location: Uruguay

Re: HVAC replacement parts

Post by Ju@n »

Your list is pretty ok, another thing to check, if you have a "later" car with an electronic middle slider (you'll know since the middle slider won't have a physical metal wire). Check that the small motor and sensor work ok, when you remove the dash (at least the lower parts) you'll be able to see it actuate.
DavidE9
Posts: 144
Joined: Apr 22, 2012 1:29 AM
Location: Encinitas (LA is a shit show right now)

Re: HVAC replacement parts

Post by DavidE9 »

I'm in the middle of the same job. It was recommended to me that I replace the AC resistor while I was in there. I have an extra part, but realoem shows it as being for an E30. As near as I can tell, the PN is 64111373771--which you might be able to make out in the photos below.

If you think it will work for you, send me a DM and I'll send it off to you at no charge. Its never been installed or used. Somehow every job I do I end up with extra new parts...

https://share.icloud.com/photos/00cpUce ... IFNXvqNO9Q
https://share.icloud.com/photos/079s7pH ... IXLibIZmHw
https://share.icloud.com/photos/001HOPO ... YgqLFW4pvw
DavidE9
Posts: 144
Joined: Apr 22, 2012 1:29 AM
Location: Encinitas (LA is a shit show right now)

Re: HVAC replacement parts

Post by DavidE9 »

Im trying to help out Dale with his AC rebuild. RealOEM shows the AC resistor PN as 64511373277 and 64511468409. Does anyone know if PN 64111373771 will work ? It would really be unfortunate to install this part, put the AC back together only to have it not work because 64111373771 is incompatible. (or worse, cause a fire)

-D
Dale3783
Posts: 424
Joined: Oct 26, 2016 10:01 PM
Location: Miami, FL

Re: HVAC replacement parts

Post by Dale3783 »

gwb72tii wrote: Jan 08, 2022 7:05 PM I'd be curious as to which evaporator core you use, oem or something from rock auto or equivalent?

anyone have experience with the rock auto knock off?
Image
I ordered a evaporator core from Parts Geek and I'm going to return it. The lines were no where near the correct placement. I don't even think they would have fit out the hole in the side of the AC box. The quality looked decent but it was very different.

So I reinstalled the original evaporator care with a new expansion valve, foam, blower motor (original cages), and temp sensor. Glad I was careful with the old one on the way out....
gadget73
Posts: 857
Joined: Nov 22, 2017 10:30 PM
Location: New Jersey

Re: HVAC replacement parts

Post by gadget73 »

hopefully it got a good clean while it was out. Dust and dirt on the coil does a nice job of insulating it, which is not helpful for AC performance.
MyE24
Posts: 70
Joined: Apr 16, 2021 10:43 AM
Location: California

Re: HVAC replacement parts

Post by MyE24 »

I did the same job this summer on my e24.
I don’t know what’s in Austin’s kit, but for my job I didn’t buy a kit, but replaced everything with new, with the exception of the evaporator. But I cleaned the evaporator inside and out.

So:
New parallel flow condenser in the largest size that would physically fit. ($100)
New Spal high speed fan. ($150)
New genuine Sanden R134a compressor. ($200)
New AC lines (custom barrier hose). ($150)
New receiver/dryer. ($40)
New expansion valve. ($25)
Remove evaporator and chemically flush lines and clean exterior ($15 for the can of flush, $5 acetone).

Afterwards mine blows 40 degrees at the vents on a 90 degree summer day on R134a, so very pleased.

I also replaced my heater core while the dash was apart.

You say your system was flushed, but if you had that done without taking out the evaporator and removing the expansion valve, it wasn’t really flushed fully. You have to remove the expansion valve to flush the evaporator. And the expansion valve/evap is where clogs typically happen (as was the case with mine), because they are rarely removed because of the labor involved.

If your car has the AC fan variable speed transistor, you can replace that during the job, but if it’s anything like the E24, it isn’t necessary. It’s easy to replace at any time.

Be careful with the duct work. Make sure it’s all in place properly and not tweaked.
There’s a couple of gravity operated weighted flaps in the “transition piece” above the evaporator box, they are finicky and have small plastic tabs that break. Make sure they are in place and working properly (that is on an E24, but I believe the E28 uses the same thing).
Make sure your dusting is all sealed up. Often it’s not, and AC air escapes under and behind the dash. Use aluminum AC tape to seal as many of the seams as you can.
gwb72tii
Posts: 229
Joined: Sep 21, 2021 4:58 PM
Location: Washington state

Re: HVAC replacement parts

Post by gwb72tii »

How do you check if the evaporator is ok once you have it removed? I would guess a pressure check?
demetk
Posts: 8427
Joined: Aug 09, 2007 8:58 AM
Location: CT, USA

Re: HVAC replacement parts

Post by demetk »

gwb72tii wrote: Jan 21, 2022 12:39 PM How do you check if the evaporator is ok once you have it removed? I would guess a pressure check?
I pressurized it and stuck it in a 5 gal bucket. :)
MyE24
Posts: 70
Joined: Apr 16, 2021 10:43 AM
Location: California

Re: HVAC replacement parts

Post by MyE24 »

My car had dye in the Freon. I’d say many old cars do these days. If anyone ever put it in, it seems to stay in the system basically forever.
So I could see there was no leakage. My system also hadn’t been charged in 5 years and was still cooling, so I was fairly confident there was no leakage.
But yes, any way to pressurize it and put it under water would work.
It’s very important to flush it and make sure it’s flowing freely.
Before my system overhaul,my AC actually cooled a bit. Not great, but it worked somewhat.
When I flushed my evaporator and ran compressed air through it, I found it was significantly clogged. The flush fluid and compressed air broke it free fairly dramatically.
This is esp important in cars that have been converted from R12 to R134. I think 99% of the time when the conversions are done, the R12 isn’t fully flushed out, and it causes the system to eventually get gunked.
Dale3783
Posts: 424
Joined: Oct 26, 2016 10:01 PM
Location: Miami, FL

Re: HVAC replacement parts

Post by Dale3783 »

I ran a bunch of water and compressed air through mine as well. It wasn't really clogged and not much gunk came out. It was the expansion valve that was completely plugged. (hoping that was the entire problem). Then reinstalled and resealed everything as best I could. Getting it vacuum tested and charged this weekend. Here's hoping I have nice cold AC by Monday.
gadget73
Posts: 857
Joined: Nov 22, 2017 10:30 PM
Location: New Jersey

Re: HVAC replacement parts

Post by gadget73 »

its more the oil than the refrigerant. The R134a doesn't carry the old R12 mineral oil so it ends up puddled in random places. Any contamination in the system seems to get trapped in it so you get pockets of sludge that can plug stuff up. When I did the AC in my Lincoln I found evidence that the compressor and desiccant had both fragged at some point. The oil/sand/compressor gut sludge that came out of the condenser was substantial. I flushed it with mineral spirits until it ran clear, then acetone to get the remains of the mineral spirits out, followed by a long purge with compressed air to dry it.
Dale3783
Posts: 424
Joined: Oct 26, 2016 10:01 PM
Location: Miami, FL

Re: HVAC replacement parts

Post by Dale3783 »

So I got the system recharged today and I cannot believe how cold the AC is. 35 degrees at the vents at speed and about 41 at idle. Granted it's not that hot in Miami today, about 80, but I really couldn't believe it. Thanks Austin for the Sanden upgrade kit. Really, really happy.
TimU
Posts: 5
Joined: Feb 14, 2022 11:44 PM
Location: Sydney

Re: HVAC replacement parts

Post by TimU »

MyE24 wrote: Jan 21, 2022 10:54 AM New parallel flow condenser in the largest size that would physically fit. ($100)
New Spal high speed fan. ($150)
New genuine Sanden R134a compressor. ($200)
New AC lines (custom barrier hose). ($150)
New receiver/dryer. ($40)
New expansion valve. ($25)
@MyE24 - Could you share some details on the parts you bought please?
  • The exact Sanden compressor model - There are so many variants, I want to get the right one.
  • Which PF Condenser please? 16x19" appears to be the best size.
  • Any particular receiver/dryer?
Thanks in advance - I've just started down this journey for my own '86 E24.
MyE24
Posts: 70
Joined: Apr 16, 2021 10:43 AM
Location: California

Re: HVAC replacement parts

Post by MyE24 »

TimU wrote: Feb 15, 2022 2:00 AM
MyE24 wrote: Jan 21, 2022 10:54 AM New parallel flow condenser in the largest size that would physically fit. ($100)
New Spal high speed fan. ($150)
New genuine Sanden R134a compressor. ($200)
New AC lines (custom barrier hose). ($150)
New receiver/dryer. ($40)
New expansion valve. ($25)
@MyE24 - Could you share some details on the parts you bought please?
  • The exact Sanden compressor model - There are so many variants, I want to get the right one.
  • Which PF Condenser please? 16x19" appears to be the best size.
  • Any particular receiver/dryer?
Thanks in advance - I've just started down this journey for my own '86 E24.
Sure.

I got the Sanden from Summit Racing. VTA-04808-VUA
PF Condenser. 16x20 from Amazon CNFP1620
Spal fan 16” curved blade pusher 30102048
Receiver drier from Autozone - 80-8085
Hoses and fittings from Coldhose.

You can use the 16x20 PF, but you have to use the short drop fittings as shown on the Coldhose invoice.
For the condenser, the bigger the better.

You could actually use one a couple of inches taller, if you could find that dimension. The width, though, is absolutely maxed out for the space.

The problem with the condenser is the way the outlets point to the side. If they pointed forward, you’d have at least a couple more inches. If I were doing it again, I might consider looking for an 18x22, and having the outlets cut off and re-welded to face the front. But that’s probably just OCD overkill. I’m blowing 40 degrees in hot weather the way it is.

Also, I used the adapter brackets shown in my picture. They work fine. But afterwards I found out about the LC Wylie bracket. I think that’s a nicer solution, very clean and elegant. $150, but imo worth it. You can find him on Facebook.

Image
Image
MyE24
Posts: 70
Joined: Apr 16, 2021 10:43 AM
Location: California

Re: HVAC replacement parts

Post by MyE24 »

Pic links
Take a look at my Coldhose invoice, it has all the part numbers and pictures, it’ll help you out.

https://ibb.co/NFXdqTr
https://ibb.co/NTr1HvF
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