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Jul 27, 2012
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Brisbane - Australia
My Car
1973 Mustang Convertible
Hi to all,

Just wanted to give the Forum my ongoing adventures regards my Classic Auto Air conditioning system.


Back around 2013, i purchased a new Classic Auto air Elite system for my '73 Convertible(non factory air). I had the unit professionally installed by a fully qualified mechanic/fridgie. The system seemed to be functioning and performing ok after installation. Although, i have always been disappointed with the volume of air and air force or velocity the dash vents put out. However, a couple of weeks after the install, the water heater control valve malfunctioned,and so, had to be replaced with a genuine part from Classic Air. Back then the part plus shipping costs added up to be around just over the $200.00 US mark. ($290.00 Au) However, i am guilty of not using my air conditioner all year 'round, year in year out. In that sense, installing it in the first place has proven to be somewhat of a white elephant.

That brings us up to today,as i went to turn on my aircon the other day when out on a weekend cruise. Being a hot summer's day, i set the controls to blow out cold air. I got very hot air coming out of the dash vents instead.
I then got my mechanic to look over the whole system to see what was wrong. He discovered that again, i had another broken heater control valve that was not functioning at all. This was bad news. I phoned up Classic Air, and spoke to a tech for help and advice. He said i had two options. I could purchase a replacement valve the same as mine, or update and buy a newer version of the valve. If i bought the newer version, then i had to buy an extra
wiring harness to go with it it as well. Lets talk money costs here. The older valve on its own was $70.00US plus UPS Shipping costs of $100.00 - (that's a total of $270.00 Australian Dollars). If i wanted to buy the newer version of the valve, the cost would be more. $220.00US. (That's $348.00 Aus landed in Oz.) As you can see, it's very expensive to replace these units, especially the older model, which has proven to be unreliable to say the least. Classic Air only offer up UPS to their customers. There are no other cheaper options with them to post out to Australia.


Being way too expensive to replace and running the risk of future failure and break down, i have decided to take a basic, simple and cheaper option to get out of jail. Simply, i will be installing a cheap water ball gate valve on my heater hose line running from the intake manifold back to the bottom inlet heater core pipe on the firewall. (cost is $32.00 Aus) This will bring about a result of not letting any hot water enter the heater core. Since i never use my aircon or heater all year 'round, using the ball gate valve won't be an issue. But if i do, i know in summer i can close off the hot water to the core, turn on the cold aircon, and enjoy the cool, and in winter, i can open it up for cabin aircon/blower warmth. So basically i'm going to a manual control valve over an unreliable, expensive electro/mechanical valve.

There is a bonus here too. Over the years, i have noticed driving around, that the cabin gets hot (summer or winter) without using the aircon or blower at all. What's going on here is that hot water coming from the intake manifold, and going into the heater core, whether it stops at the core or continues on back out to the water pump or not, produces a radiant hot effect in the cabin. The Classic Air water control valve is located on the water pipe that comes out of the top heater core pipe on the firewall. Why they decided to locate this valve in that position escapes me, as you end up with a current situation of hot water being allowed to sit or pass through the heater core all the time your engine is running, and thus ends up causing this unwanted heat problem in the cab all the time your driving around. By installing the ball valve, it will eliminate this past unwanted heat problem completely. My currently installed broken water valve which is stuck in the open position, will be left alone and not removed as such.

This solution then is the obvious way to go for me. Lastly, i want to make comment on the crazy rising costs of buying spare parts for our Mustangs these days. I know we all are living in bad inflationary times, but my heart goes out especially to all the international Mustang owners around the World who have to cope with extra expensive shipping costs, varying dollar exchange rates and import duty taxes. This makes importing any parts, big or small from America very expensive.
For me, i can easily double the price of any part bought in from the States and landed on my doorstep. For example, lets say i buy a part worth $120.00 US. That same part will easily end up costing me over $240.00 Aus when landed at my door. The bottom line is that this classic car hobby is getting to be very expensive now, as we all need to keep on buying parts ongoing as our cars get older and deteriorate more. Yeah, not really ideal unless you have deep pockets, and it doesn't matter. Rising costs will have to have a negative baring on future ownership of classic cars worldwide. It well may ending up that way for me in the future. Sorry, i can't afford it syndrome.

I know a lot of Forum members have commented on that they like and have been happy with their Classic Auto Air systems as such, but for me, it has not been a good experience really all 'round. I wonder where their parts are made that make up their systems? America maybe? :unsure:By the way, i learnt the other day that Classic Auto Air and Vintage Auto Air are one and the same companies. Interesting. Why don't they merge and just call it one company name, like Classic Vintage Auto Air, and save everyone unnecessary confusion. If the mozzies dont getcha, the gattors will.

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I love your fix to the problem. It reminded me of my 1990 Honda Accord wagon. The heater control box on the dash broke, and was replaced. Since that time, I was unable to get much cold air out of my AC. It took it to an AC specialty shop, and they said they needed to replace the entire AC system for $1700. I went to another place, and we went for a test drive. After coming back, the mechanic opened the hood, pushed on a lever, and all of a sudden, I had lots of cold air! WTF? It turned out that the cable that turns the hot water off when in AC mode was not quite the right length or it needed to be adjusted when the replacement control box was installed. The mechanic said he could spend a few hours adjusting things, or I could simply push on the lever once summer began and I needed cold air. I chose the latter. The cost was $60 for diagnosis, and that shop became my go-to place for honest repairs.
Just some food for thought that might also work for you. Below is a standard valve for the heater and is in the closed position when vacuum is applied. You could go this route and run a vacuum line off the manifold to inside the car with a switch and then back out to the vacuum solenoid. That way you could control the heat without having to get out of the car and under the hood.|tkp:Bk9SR8q1uYrOYQ
Just some food for thought that might also work for you. Below is a standard valve for the heater and is in the closed position when vacuum is applied. You could go this route and run a vacuum line off the manifold to inside the car with a switch and then back out to the vacuum solenoid. That way you could control the heat without having to get out of the car and under the hood.|tkp:Bk9SR8q1uYrOYQ
Hi Kilgon,
Thanks for your reply and input. Would you believe that i have investigated that setup as you describe as a possible get out of jail solution to fix my problem of the ongoing failure of the Classic Air heater valves. To me, it's not a bad idea all up. I am aware that most modern day cars run this vacuum control setup for their heater control units. I could do this myself, but i have discovered that even the vacuum units are prone to playing up as well as the electro mechanical ones do. On that basis, i could go to the expense and trouble of setting up the vacuum system, only to have potential failure issues down the track as well.

Another option i was considering was to buy a simple dedicated mechanical heater valve that comes with a cable and a push/pull knob that gets mounted under the dash. You simply push or pull the knob in or out when you want to open or close the heater valve. In my opinion, that would be a better way to go
for a system that would or should last a long time as adversed to the mainstream fancy valves that play up and break down. Those basic cable control set ups are quite cheap as well. I decided not to go with the cable system for now, as the lever ball valve install idea was the cheapest, easiest, effective option for me right now. I can take up with the cable set up later on if i choose.

In any case, thanks again for suggesting the vacuum system for me as another fix it solution.

Greg. (y)