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On 02/05/2020 at 15:49, Peter M said:

Air Conditioning

I had the AC regassed at the end of last year but by March it was evident that it was losing pressure and I likely needed to replace a few of the original hoses.  I was also interested in improving the airflow in the cabin and spent some time understanding how the ducting worked on the later 3.2's and replacing seals in the fresh air system to make sure I wasn't having the hot external air mixing with the refrigerated air.

I also tested the airflow directly from the evaporator box and found that impressive but even though the route is reasonably direct in the later 3.2's, I couldn't work out why it should be so much less forceful by the time it got to the driver's side vent.

At the same time I was chasing a refrigerant leak in my XJ6 and at over 200 bucks a regas, I though this was expensive and somewhat environmentally insensitive.  I had noticed the cost of a vacuum pump and gauge set on eBay was about the same cost as a  professional 134a regas.  After a bit of a hunt around for Hychill suppliers, I decided to set myself up as a DIY air conditioning mechanic.

 

1Q9s8vM.jpg   

The XJ, like every old car I've had required a full AC rebuild, including an 6 hour dash out evaporator replacement.  That wasn't too bad as my 993 as it took 10 hours to do the same thing, but from the frunk side!

a0x4rqX.jpg 

Evacuating the system after replacing a hose end fitting that didn't give the clearance to the chassis that I wanted.  Vacuuming the system before recharging with Hychill Minus 30.  I've only replaced a few AC items on the red car so far - receiver/dryer, front condensor, evaporator and blower motor - but I foresee at least upgrading all the old non-barrier hose as my next job.

As an example of my peerless timing I now have the AC working well in both cars.  It's just that the temp expected here today is 12 degrees with an overnight low of -2! 

Love your work - did something similar with an E39 touring - complete dash out, can't remember now but job was 15 or 20 hours all up.   A professional quote was more than the car was worth.  There is something exceedingly satisfying about sitting in a car with cool air coming from the vents from your own handiwork.

We all groan a bit about modern cars but I do find they come apart and go back together pretty well, even if there is a lot of lego pieces.

What vent temps are you getting on the 911?  I'm jealous of your crimping kit - I have a 911 AC re commissioning in my future, but probably will buy a kit with the pre-made hoses.

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4 hours ago, Coastr said:

Love your work - did something similar with an E39 touring - complete dash out, can't remember now but job was 15 or 20 hours all up.   A professional quote was more than the car was worth.  There is something exceedingly satisfying about sitting in a car with cool air coming from the vents from your own handiwork.

We all groan a bit about modern cars but I do find they come apart and go back together pretty well, even if there is a lot of lego pieces.

What vent temps are you getting on the 911?  I'm jealous of your crimping kit - I have a 911 AC re commissioning in my future, but probably will buy a kit with the pre-made hoses.

Thanks Coastr!  I remember your comment from a few years ago about how a E39 is literally built around the A/C evaporator.  I agree resurrecting non- working A/C to provide a chill is something I find quite satisfying and a necessary part in having a drivable car rather than a garage queen.

Modern cars (ie  post 1990 and in the Lean manufacturing era by my definition) are so nice to work on from a electrical point of view, nicely laid out, standardised connectors that are impossible to assemble incorrectly.  A long way from a G Model with their million spade connectors that rely on you not being colour blind.  Not so convinced about the longevity of the screw free, clip together plastic parts when they are a couple decades old though!

I haven't measured the vent temperatures since I've recharged with Hychill Minus 30 but have bought a new thermostat this week as my last drive was unpleasant as I couldn't adjust the temperature high enough and had to manually turn the A/C on and off as it was too cold!  What I have realised is that good A/C, like modern cars, requires lots of air flow volume, relatively low air velocity and vent temperatures not less than about 6 or 7 degrees C.  Not something a G model and earlier 911's are known for!

Consequently most of my thoughts have been around how to increase air volume and have actually bought a anemometer to do some testing and some comparisons with modern cars to better understand what changes I need to do.  I even picked up a 70's Behr under dash vent setup last month just in case!   Yes, good A/C is important to me.

Don't be jealous of my crimper, it was cheap and I broke the jaw return spring after it's first use!  I have used a premade hose kit before in my white gold car but with the exchange rate now, they're not cheap anymore.  However the barrier hose and fittings are still pretty inexpensive at around $22/m and 20 bucks each, generally readily available off eBay and quick to assemble so I thought 'why not?"

The plan is to do some testing, work out what modifications I want to do and then do it as a job lot at once.  

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A simple AC thermostat change became more complicated when a spade terminal end pulled out of the AC power  harness socket behind the evaporator.  That meant removing the evaporator and a rush regas the day before our drive day today:

QYelVO5.jpg

 

I need not have worried as it was about -1C north of Walcha this morning!

NGN9xFN.jpg

 

 

But a great day nevertheless:

8saZ5zs.jpg

 

 

 

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On 27/06/2020 at 21:36, Fishcop said:

Looks like checking out the 928's engine was a harbinger ;)

Last check before it went up in smoke, i wonder how he got on?

8saZ5zs.jpg

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