Mike’s Retrofit Aircon Cruise Heated Seats ++

Big day tomorrow:
Booked in with Kwikfit to have the Aircon system pressure tested, and if it passes, vacuumed, and re-gassed 🫣
🤞
 
🙁
It has a leak………

So now booked in on Monday with a “proper Aircon garage” who can dye test to identify where the leak is.
- ( bit unfair on Kwikfit - as they can’t/don’t offer leak tracing, but don’t charge for a failed pressure test).
 
Look at every joint for the telltale green juice leaking. All across the condenser and around the compressor pulley. It’s likely just a pinched O ring on a fitting.
 
Thanks Andy.
Kwikfit did a vacuum test first and their equipment showed up a leak, so I’m guessing they will not have added any coloured gas that would help reveal the leak?
But I do hope you are right and it’s no more than a twisted seal: hopefully Monday will give me a better idea.🤞
 
Halfords sell a canister for topping up a/c. Also a little valve with pressure etc. Might not be enough to do a fill from empty but it might show up where the leak is. Of course you shouldn't do this at home kids if you know you have a leak because of the environment, greenhouse gases etc.
 
🥲
The “proper garage” found the fault very quickly.

One of the bolts securing the new (very hard to fit) fan shroud has pierced the new condenser!🥲🥲🥲

But at least I know what the (prime) cause of the leak is (though I don’t know if there are any other leaks).

I’ve ordered a new condenser - a Mahle version this time as I believe they are the OE supplier to BMW and hope it is a better combined fit with my fan shroud than the Nissens unit I originally fitted. Since I am still “quids in” on the sale of donor parts over its cost, I’ve also ordered a new drier unit (£20), as it makes sense to avoid much more expensive failures later on.

Oh well!!…….Onward and upwards!🥴
 
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Halfords sell a canister for topping up a/c. Also a little valve with pressure etc. Might not be enough to do a fill from empty but it might show up where the leak is. Of course you shouldn't do this at home kids if you know you have a leak because of the environment, greenhouse gases etc.
Just for information.....the 'gas' Halfords and the like sell is NOT proper refrigerant. It is a mix of other stuff which 'acts' like R134a (or whatever you have) but doesn't have any 'CO2 equivalent' chemicals so can be sold over the counter. It is not good stuff and I would advise against using it. It can do more harm than good.

No-one is allowed to sell proper refrigerant unless they have a licence to sell it and it is registered. And no-one is allowed to buy it unless they have a valid 'F-Gas' qualification and are registered. Refrigerants (beginning with R then three numbers) are now (and have been for a long time) highly controlled.

Also deliberately venting refrigerant to the atmosphere (ie if you know you have a leak and put refrigerant in the system) is against the law and can be punished by prison or an unlimited fine (or both).

Using refrigerants if one is not competent, ie qualified and experienced, can also be extremely dangerous. It is not the kind of stuff to play around with.
 
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Interesting.
The “proper garage” - LRS at Sutterton - came across as very competent and very pleasant.
The guy doing the test used OFN (Oxygen Free Nitrogen) to pressure test for a leak: he mentioned it was illegal to test with R134a in order to find a leak - and ushered me out of the garage whilst he did the test. He let me back in immediately after to show me on his mini camera probe where the securing bolt had punctured the condenser.
Despite the disappointment I was very impressed with their set up: very clean: very organised, and all happy to have a chat about cars.
I’ll be using them again
 
“You pay for your learning……”

IMG_8250.jpeg


The longer fixing bolts I ended up using to bolt the poorly fitting fan housing to the condenser were marginally too long, and when tightened, fouled the condenser!🫣 causing a big leak.
Sod’s Law: if the fixing bracket had been 2mm higher the bolt would have missed the tubing and just fouled the cooling fin.
As my very clever Father in Law often reminded me : “You pay for your learning”, so a new (expensive) condenser is on its way, and I’ll find some 10mm shorter bolts for re-fitting.
 
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These days it’s probably cheaper to buy a new one!
I certainly can’t weld aluminium, and tradesmen prepared to do it these days are few and far between and can charge what they like.

At my age, I’m running out of healthy time faster than I am funds! So I’ve ordered a new one.
Hopefully it will be a better fit than the Nissens!
 
Can you not get that soldered up?
No, not really. The pipework in a/c condensers is extremely thin aluminium (for efficient heat transfer and light weight). Then the fins are also ally, which will melt with any heat.
Welding ally is an art. Welding ally there is another level of art. Even of you could weld it, chances are you would block the tube with weld.
 
……… it’s been a long time coming………but

I have my Aircon WORKING! 🥳😊

Took it back to LRS at Sutterton ( more impressed with them each time I go): they did an OFN Nitrogen pressure test first for 10-15 minutes, purged it, and re-gassed it (apparently Z3s have an unusually large quantity of coolant) and checked it worked well.

Only fly in the ointment is my Aircon fan is not kicking in, so I have some electrical circuit testing to do to see why?
This b****y fan has caused me SO much aggravation 😡😤Grrrr!!!


After a quick cuppa, a methodical plan is coming together for testing the electrics:

Apply 12v to the fan plug to test the fan
( Edit : It works : both slow and fast)

1. Now that the Aircon system is pressurised switching it on should start the fan running, so a simple voltage test across the loom’s fan plug should show if the circuit is working to that point.
2. If that fails, the temperature sensor in the radiator should kick the fan in to both high and low speeds, so again I can test for voltage at the loom’s fan socket.
3. If both 1 and 2 fail I’ll have to check fuses and relays which could prove time consuming!
Electrics are not my strong point🙁
 
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So nearly there……..!

With 12v across the fan it worked, both slow and fast ! Yeah!

Howrver I couldn’t get it to come on with the Aircon switch, which I believe it should.

A quick test, bridging action terminals to the radiator Aircon sensor pulled the fan in.
A further test bridging the Aircon pressure sensor aldd sf o pulled the fan in.

So, as it stands this evening, everything works exactly as it should, with the exception being the Aircon cabinet switch, which doesn’t automatically pull it in.
If anyone reading this can confirm that switching the Aircon on in the cabin always pulls the Aircon fan in it would be really useful, thank you.

In the meantime I’ll do a bit more internet research and delve into the circuit diagrams on RealOEM to see if they throw any light on to what’s happening.
 
If anyone reading this can confirm that switching the Aircon on in the cabin always pulls the Aircon fan in it would be really useful, thank you.
I can't confirm it on the E36 Mike, but I know on the E89 the a/c switch DOESN'T trigger the electric fan. It only works from the high pressure fridge switch, so cycles with a/c condenser pressure. I don't know about the other models but would imagine BMW took this route with many models.

Best way to check is to run the a/c. As long as you know the high pressure switch is good, you won't do any damage if the fan doesn't kick in, as the HP switch will cut the compressor before anything goes bang.
 
Thanks Andy, unfortunately I can’t see these well enough on my screen to follow them.

Is there anyone who can fully interpret the Realoem circuit below:
Edit: This hasn’t come across any better!

The Aircon cabin switch feeds into “The Evaporator Controller” which I assume is within the main ECU.
I can follow the circuit from the Evaporator Controller but clearly have no idea how the Controller is programmed to provide a switch on signal to the rest of the circuit. It can not be a direct switch from the cabin switch, otherwise the Temperature sensor that feeds in to the Controller has no impact?
 

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If it's any help to you.
on my 2.8 (March 1999) with aircon from factory, when I start the engine from cold and switch on the air con from the dashboard switch
my fan (currently semi seized) does kick straight in......... some times needs a nudge to get it going ;)

I hope that helps rather than adds to any confusion.
 
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