AC Evaporator and Low Pressure Switch

After getting the radiator and all subsequent leaks stopped it was time to move on to the evaporator core.  I destroyed the threads on the old one when I was trying to install the AC dryer.  On these cars you remove the top half of the air box and the evaporator just sits inside.  These boxes are very easy to break or crack as they get older and there is a urethane material that seals the two pieces, so it can also be easy to damage the pieces when attempting to pry them apart.  I got mine apart without further damage than had already been done by the individuals that had worked on it previously.  I also found that the last person to install the orifice tube had put it in backwards.  One small silver lining is I was able to thoroughly clean the air channels while I had this apart. 

This is what the area looks like with the top removed.  I used a putty knife to help separate the two halves.  The evaporator sits inside a cradle with no mounts, only soft strips to insulate it from vibration.

After the evaporator was out I had to scrape all of the old sealant off of all of the mating surfaces.  The worst part about this was that I had already sealed the top and side of this box to the cowl when the fender was off.  These areas are very prone to leak on these cars and I used windshield sealant to seal the area the first time, as was shown much earlier during this LS swap project.  Now I had to re-seal it again, but this time with the fender on, so it was more difficult.  I took a vacuum and cleaned the the bottom of the air box, then wiped it down with wet towels.  I had never had this off of one of these cars so it was interesting to see in person, not just a drawing, how the hot and cold air is directed through the car.

The sealant had dried so I tried to poke down until I made an exit, but the bottom of the tube was apparently dried too and the caulk gun wouldn't budge.  I had to cut the tube with a hacksaw to get to some of the usable middle parts.  I used windshield adhesive strips to seal between the upper and lower part of the air box, which worked great but I wasn't thinking and put them on the upper side of the box.  It is a tight fit and I couldn't get the box installed without messing up the sealant, which of course should have been obvious to start with.  I ended up having to remove all of it and then install it on the bottom part of the box and then sit the top down on it.  This, the correct way, worked much better.

After getting the evaporator back in I installed the AC dryer.  After getting that on I moved on to the final piece of the AC system that I'll have to make, since I'm going to have the remaining two hoses made at a hydraulic hose shop.  This is where I did something very stupid.  Because I had ruined the old AC dryer I had to order another one and I had to piece together parts from various different vehicles to get it all to work.  Also, it's been several months since I had worked on the AC wiring.  I knew that I had cut the end of the low pressure switch off of the original harness but I couldn't find it anywhere.  I had the new low pressure switch that I was going to be using and I remember that I had test fit it and it worked but I couldn't find the end I had cut from the original harness anywhere.  I tend to keep things of like manner together so I don't have problems finding them later on, but I still could not find this thing and I ended up spending several hours over a couple days cleaning out and searching through my garage.  I finally realized that I was trying to find something that didn't exist.  For some reason throughout this process I had ended up with a new R12 low pressure switch, which has a very large plug in the end for the harness and that is what I was trying to find.  I finally realized that the R134A low pressure switch is the one that I had finally determined I was going to use and one of the pigtails I had in the box fit it perfectly.  I had a couple different pigtails because the place I ordered it from (Summit I think) had an issue with their computer system saying a few different part numbers fit the same application, depending on how you looked it up.  They ended up sending me more than one and told me to keep the ones that didn't fit.  After I finally remembered all of that and remembered which new pieces were right and which new pieces were wrong I finally realized I'd had them in front of me the whole time.

I then found another issue.  The low pressure switch is just a ground from the PCM with a switch in the middle.  The pigtail from the switch has two wires so I expected to find two wires in the harness that I had put aside, but I found that there was only one wire there when I un-taped everything.  In short it turns out this is because I was combining multiple types of AC systems in order to get the computer to be able to control the AC system.  The issue stemmed from the fact that the original compressor had a ground wire coming off of it, which the low pressure switch would tie into. 

My compressor doesn't have a ground wire because it grounds through the case and mount.  It only has one wire coming from it.

I could have spliced the ground wire into the existing hardness somewhere, but there were a couple of reasons I opted not to do this.  To access the back of the harness for soldering I would have had to remove a large portion of it from the car, which would have taken a long time.  Also, just finding a ground and splicing in this ground could cause issues with having two pieces of harness now tied together that later I would wish weren't permanently together.  I opted to run a dedicated ground and attach it to the back of the passenger side cylinder head where the other grounds from the harness attach.

Then I soldered in the other end of the low pressure switch pigtail with the existing wire from the engine harness.

Below you can see the new ring terminal for the ground.  This ground bolt is somewhat difficult to remove and install because the transmission dipstick is so close to the bolt.

Here is what the finished product looks like.  After getting all the wires in a loom and taped up with black tape all I need now is a hose made to run from the AC drier to the compressor and one from the compressor to the condenser and I should have AC, which is good because some days are starting to get hot, which is OK with me, but the wind can be a bit much for two young girls with long hair sitting in the backs seats.

When I went to move the car after getting everything put back together I noticed the pedal felt weak and the brake light was on.  I checked the master cylinder and found that the rear pot was empty, so I suppose the next step will be finding the leak which will most likely mean new wheel cylinders and hoses for the rear.

Radiator Bleak

I have found that when you work in a tightly confined office setting and have two small children, if everyone gets sick, you might as well get ready.  Some sort of sickness went around and people at work got it, then my wife got it, then both my children, who have a propensity for coughing directly in your face, got it.  I held out pretty well for a while, but finally it got me.

I had planned on putting an aftermarket radio in April's '97 Lumina so she could hook up an MP3 player.  I really don't like the look of aftermarket radios and after looking into it a bit I found that you can modify older radios to add an auxiliary input for an MP3 player.  April and the kids were out of town for a week so I used the time to tackle the project.  There are several different ways to go about doing this depending on which version of the AC Delco unit you have and how you want it to function.  My cousin who had given us the car used to drink coffee and Coca Cola a lot and the buttons were always getting stuck because the cup holder is right against the radio in these cars so while I had everything apart I cleaned it all with soap and water.

The front lights were also burned out on the radio so I ordered new LEDs.  I ordered red ones because I've always liked the look of the red and orange gauge and dash lights.  The old bulbs had to be de-soldered from the circuit board and the new LEDs had to soldered in their place.  The new LEDs had internal resistors so they had to be oriented in the correct negative/positive direction, which meant following the directions was key.

I decided to go with a five pin aux jack, which automatically interrupts the signal and activates the jack when the aux plug is plugged in.

I installed the jack on the back of the radio, visible below in the upper right hand corner of the radio.  I ran an aux extension cable out of the back and up through the middle console/armrest.  My hope was that when the Ipod was unplugged from the extension cable it would kill the signal, acting as though the aux jack was unplugged.  This ended up not being the case and as it is now only the CD player and Aux work with no radio function because the aux jack is always activated due to the fact the extension is always plugged in the back.  I'm going to relocate the aux jack to the front of the radio so that the cable can be unplugged when someone would want to have the radio on.  Also, whatever varsity GM engineer that designed the dash bezel on the Luminas needs to be found and shot.  I ended up breaking the dash bezel into something like 5 different pieces.  I'll need to take a trip to the junkyard.

I started having an anti-freeze leak that I couldn't get to stop.  I couldn't exactly trace where the liquid was coming from.  I would tighten clamps each day and check again, but the leak would get worse and worse.

I finally determined the leak was coming from the radiator itself, where the fin and tubes were connected to the tank on the passenger side.  It was hard to find the leak because it was leaking down the inside of the radiator and coming out of the bottom.  I found others have had this issue with their new radiators as well.  I was afraid that Griffin would not replace the radiator, or that they may try to charge me for shipping.  This was not a cheap radiator and I was not about to pay anything to have it replaced.  I was already going to be out all of the time I had in finding this problem and removing and replacing the new radiator and the cost of new fluids.  If this had only happened a week earlier; the airflow block-off plates would have been way, way easier with the radiator removed.  This picture with the radiator out gives a better look at how they block off the air gaps.

Fortunately, I remembered that I had bought the radiator through Summit Racing.  In every experience I've had with Summit they have had absolutely great customer service in every way.  Once again, not only were they very polite but also accommodating to my problem.  They sent me a new radiator and had UPS pick up the old radiator. 

Taking the old radiator out was no problem.  I found that removing the transmission lines was hugely improved by removing the electric fans.  It was easy to remove the fans, with only 6 easy to reach metal screws, but I couldn't put them back in with the radiator installed because of the way the lower mounts were made.  I would have to pull the radiator each time I wanted to install the fans and install them together.  This was a huge problem because installing the transmission lines with the fans installed is possible, but barely.  To solve this problem I was able to trim the bottom of the electric fan shroud so that I could install the radiator and then slide the fans in to place afterwards.  This did not compromise the strength or integrity of the shroud in any way so it appeared to be the perfect solution.

I had to buy some cutting wheels for my dremel so I could get a hole big enough to fit a metal saw into.  The aluminum was thick and the dremel didn't like it at all.  I was amazed at how expensive tiny cut off wheels are for dremels.

With the cut outs I was able to slide the fans into place.  I had trouble getting the transmission lines to seal, which meant I ended up taking the fans in and out several times.  I found that this was a difficult process until I learned the sequence.  There was a very specific sequence of things to do and remove that allowed the fans to slide out, but before I realized that sequence it was pretty difficult.  The problem with the transmission lines were the fittings between the lines and the radiator.  These fittings use a straight threads, which requires a sealant.  I had tried using a liquid Teflon tape sealant but apparently I wasn't using enough.  In the end I used regular Teflon tape and everything sealed up fine.  Hopefully this radiator will hold up better than the first one.