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Discussion Starter · #1 ·
Hello!

I suspect that my heater core is leaking, because this winter I have had coolant getting to the inside of the windscreen of my 9000 and now the A/C won't work. It was hard to remove, and tasted sweet. So I guess it is coolant, which always disappears in my car (might have a blown head gasket as well...one thing at a time ;) ) I never have any coolant in the expansion tank. That is another problem though.

As I said, I suspect the heater core is leaking since the coolant get into the inside of the car and now in the heat of the summer I have discovered my A/C is not cooling at all. So I will change the heater core first and I expect that the old one is rusted to bits.

What do I have to do after that? I want to do as much as possible myself to save some money, but I'll have to ask some local guy do a vacuum test of the system and maybe asking him fill up the system with gas as well.
What do I need to replace or prepare to make the repair successful? Any gaskets that must be changed? Any filter? Oil check? I do not know exactly how the A/C system works in the 9000.

What I just realized is that the A/C system should not leak any of the engine coolant. What other components are often starting to leak coolant or cooling gas on these cars?

Any helpful advice would be appreciated.
 

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If you're willing to depressurize the A/C system, removing the evaporator will make the heater core replacement easier. If you do, check the fresh air motor.

Replacing the blower motor at the same time is usually recommended.

The TXV bolted to the evaporator is inexpensive and might be a good preventive maintenance item.

The A/C system needs a new accumulator, vacuum and charge each time it's opened, so replacing any questionable components (especially the compressor, if original) could save you trouble and expense later.
 

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Discussion Starter · #3 ·
Twinsen, thank you for your quick and concise answer. Just what I was looking for. ;ol;

Any way of checking the condition of your compressor? I have no idea if it is changed or not before the car became mine. However, they are really not cheap and I think I will have to let it be and hope it will not break during these last years of university studies.
 

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There's no easy way to tell how much longer a compressor will last.

If cash is tight and the system has a slow leak, you might get by with adding refrigerant every so often.

You'll have to decide how important A/C is and weigh it against more serious problems your car may be having.
 

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Not to be grim but if you're losing coolant (radiator fluid) at the levels you imply I would deal with that first and foremost.

You can have a shop do a simple test (sniffer test) to detect exhaust gases in your coolant system--this will tell you if you have a head gasket failure issue.

If you were losing that much coolant from the heater core I should think you'd see a puddle on the ground at some point or the space between the bulkhead and false bulkhead would be full of coolant.
 

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How quickly does the Exp tank Empty.
Fill it to the Max Line, check it daily Or more.. and keep notes.
Could be a massive leak or a minor one. Without a time frame/measure it's an unknown.
As for Your AC. Does the Compressor Clutch engage, ie: does the electro clutch spin up the compressor when the AC is set to max.
IF not... the usual suspect is Low (or Lack of ) Refrigerant charge.
Add a Can via a DIY kit, easy and cheapish.
Then try and see if it Cools.. it should. Often older AC systems have small leaks.
It's often easier and more cost effective to add 1 or 2 cans of refrigerant over the cooling season than to spend Several Hundreds of $$ "trying' to patch the leak.
Don't be opening it up OR taking it apart without Good and proven reasons.. just a waste of $$ and time.
PS evaporator only needs moving an inch or so to facilitate blower Re and Re work. No need to break any AC connections.
 

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FWIW - pretty much 2 X everything davide says.

1. Replace the heater core.

2. Fill coolant system (allow entrained air to bubble out). Monitor tank level.

3. If your A/C system was working, but then lost capacity over time - and now does not work at all - it may simply be low on refrigerant. One of these:



and a couple of cans of 134a added slowly often returns the system to fully functional.
 

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Discussion Starter · #8 ·
Hmm, I did pour almost 1.5 liters of water into the expansion tank to get the level to MAX. It might have been too long since I filled it up. But I never have any problems with my temperature, it's always too low actually. The temperature needle won't go up further than 8-8:30, and the OBD2 USB dongle with the Torque app shows a temperature of around 90 degrees. Which is weird, because I have too little coolant in the system. Also, there are still a lot of crap inside the hoses even though I flushed the whole system a year ago. I guess I'll have to do another flush. But what I really wanted to say is that I filled the coolant system up and will check how long time it will take to get to MIN.

Davide c asked if my compressor clutch is engaging. How do I check that? I did not have any help today, so I had to film the compressor wheel while shutting the AC off and on. (Both with ECON and also turning the ACC system off with OFF) I can not see any difference though but I uploaded the clip anyway so you could check it. Maybe I filmed it at the wrong angle?
The clip

I'll see if I can find a DYI kit here in Sweden. Otherwise I have to ship it here, or ask some local coolant guy fill it up for me. What kind of refrigerant gas is used in our 9k's? R12? R134a?
 

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The temperature needle won't go up further than 8-8:30, and the OBD2 USB dongle with the Torque app shows a temperature of around 90 degrees.

The temperature gauge is not really a good indication of actual coolant temperature - 8-8:30 is reasonable. I would trust your scanner reading 90C = 195F - perfect.

But what I really wanted to say is that I filled the coolant system up and will check how long time it will take to get to MIN.

With your heater core leaking as you describe, this will be a useless endeavor. From reading your initial post, it is apparent that you are aware that engine coolant is being lost from the heater core. If you know you have a coolant system leak, repair it first and then fill/monitor the coolant level in the reservoir.

Davide c asked if my compressor clutch is engaging. How do I check that? I did not have any help today, so I had to film the compressor wheel while shutting the AC off and on. (Both with ECON and also turning the ACC system off with OFF) I can not see any difference though but I uploaded the clip anyway so you could check it. Maybe I filmed it at the wrong angle?

Yeah, unfortunately the clutch is not visible in the clip you posted. Here is an image that shows the clutch and a little description of when it should be engaged:

 

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Discussion Starter · #10 ·
I thought the heater core under the aquarium is a part of the A/C system? Or is it a part that could leak coolant (which I thought first, but then realized it was a part of the A/C system). I'm a bit confused right now. :confused:

And Chengny, that picture was really helpful.
Thanks, I'll go check the clutch. But I guess it should not be engaging if the pressure in the A/C system is too low, right?
 

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The heater core and A/C evaporator are two separate exchangers.

The heater core uses coolant as the working fluid and the evaporator uses R134a.

Failure in one circuit doesn't affect the other.
 

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But I guess it should not be engaging if the pressure in the A/C system is too low, right?

Correct - the pressure in the receiver must be at least 2 bar to allow the A/C relay to pull in and energize the compressor clutch.

Pressure Switch 166
Switches L and H are safety switches to protect against too low and too high refrigerant pressure. They are normally closed but switch L opens if the pressure drops below about 2 bar. At outside temperatures below 0 °C (32 °F) the pressure will not be higher than this and switch L deactivates the system (or if the system is undercharged).

I thought the heater core under the aquarium is a part of the A/C system? Or is it a part that could leak coolant (which I thought first, but then realized it was a part of the A/C system). I'm a bit confused right now.

The heater core is technically part of the HVAC system but is distinct from the refrigerant (A/C) system. The refrigerant system and heater core are both required to properly "condition" the cabin atmosphere. The heater core connects to the engine coolant system and transfers the heat from the coolant to the cabin air when required. The piping arrangement looks something like this:

 

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Discussion Starter · #13 ·
You've all got some useful knowledge. Thanks guys for educating me. ;ol;
I'll have to change the heater core as a first step.

But I wonder where the leak in the A/C system is. Is using smoke a bad idea? Will it damage or contaminate the system? If I blow it out with compressed air and vacuum the system after replacing the leaking part that will probably work, right? I will try to fill it up a little bit first though, and see how far that takes me.

Thanks, I'll keep you updated with any progress.
 

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You can trace leaks in an A/C system without taking it out of service.

Buy a refrigerant with UV dye. If it leaks, you'll be able to find it with a blacklight.
 

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Discussion Starter · #15 ·
Hmm, I'm quite tempted to actually buy some kit with both vacuum pump, fitted hoses and a manifold gauge. That's way easier than putting it together myself, since I do not even have a vacuum pump. I'm certain everything will come in handy later on as well. I've found some gas at a local hardware store so this should be what I need to be able to do it more times as well.

What do you guys think of something with that low price? Rubbish? Or might it work even though the price is ridiculous? Just the manifold gauge is more expensive here in Sweden, and the compressor costs more than this kit. I'll only save about 50 USD giving the job to someone else, and I'll probably have them do it again later on. Would you go for it?

http://www.ebay.com/itm/COMBO-Kit-R...200?pt=LH_DefaultDomain_0&hash=item2ee34ada50
 

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I have a similar pump and it works fine.

A manifold and pump are good long-term investments, but you need to have a thorough understanding of A/C systems before using them.

A mistake could seriously injure you.
 

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Discussion Starter · #17 ·
Yeah, I've read enough and seen enough youtube videos to know what you can do wrong. :p
I'm an engineering student, so the physics behind it and the parts of the system is not anything new. But I got confused when both my coolant leaked onto my windscreen and the A/C system stopped working at the same time, I did not know exactly how the two systems where working together in the car.

The more I learn, the more eager I get to get the whole picture. That's why I insist on keeping my old car. You learn way more about engines and other systems that are a part of cars by repairing them, than you do reading books about it at school. Also, I love 9000's. Great cars! :cheesy:

The vacuum pump from the link looks fairly small in the picture though. How much vacuum pressure do you need to achieve for a good drainage of the A/C system? Is 10 Pa enough?
 

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It's more than enough. Any water vapor not evacuated by the pump will be absorbed by the accumulator.

Before doing anything with a manifold, add some UV-dyed refrigerant with a kit like Chengny posted.

A vacuum pump will not tell you from where the system is leaking.
 

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The loss of refrigerant is most likely at the compressor shaft seal - the only dynamic seal in the system. All mechanical shaft seals leak to a certain degree and, as they age, the rate of leakage increases (wear on the faces, loss of spring compression, etc).

In most cases, the decision whether or not to replace the compressor (hardly anyone replaces an automotive A/C compressor seal anymore) is base purely on economics. If your system only requires a minor recharge (say one can of 134a per year @ maybe $10), you might consider leaving the compressor alone and just topping off every June. A Seiko/Sanden compressor probably runs about $300 - $400. Add labor costs to that and you are probably looking at close to $600. That buys a lot of SUVA.

Of course if the refrigerant leaks out so fast that you have to keep a couple of cans in the car at all times...

As far as locating the leak, dye is good in some cases. But, in a car's engine compartment, it often gets blown all over in the area of the leak - making the source difficult to pinpoint. I just use good old-fashioned soap suds (or a product called Snoop). This method can be done when the system is shut down - as long as there is refrigerant under pressure in the piping. The engine is off as well, which makes the search way easier.



You haven't yet mentioned one very important detail: whether or not the system has ever been allowed to drop below atmospheric pressure. This is critical.

As long as a refrigeration system remains even slightly pressurized (just a pound over atmosphere is enough), it is acceptable to continuously recharge to maintain capacity.

However, if a system is allowed to completely bleed off to atmosphere it will start to breathe in and out with ambient temperature changes. As a result, it soon becomes contaminated with moisture and non-condensables (air). It will then require evacuation before the addition of new refrigerant. This means if it was flat for any considerable length of time, not in the case of a small quick repair. Say for example, you dumped it just to quickly change a Schrader valve core - you could probably just button up and recharge.
 

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Aftermarket replacements for the Sanden 8052 start at around $135 on ebay, though I'm not sure of their quality.

You can also fit the cheaper and more common (in the States at least) Sanden 4691 for Jeep/Chrysler if you're willing to swap compressor heads and run a slightly longer belt.
 
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