AC Re-charge
06-19-2018 | 09:30 AM
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AC Re-charge
Is there anything special or unique about recharging a 993's AC that it couldn't be done by any competent shop not necessarily familiar with Porsche's? My Porsche guy is a bit of a hike but there's an Audi dealer down the street i was considering going to. If they had specs on amount to add and/or pressure isn't it a straightforward procedure?
06-19-2018 | 10:44 AM
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Is there anything special or unique about recharging a 993's AC that it couldn't be done by any competent shop not necessarily familiar with Porsche's? My Porsche guy is a bit of a hike but there's an Audi dealer down the street i was considering going to. If they had specs on amount to add and/or pressure isn't it a straightforward procedure?
06-19-2018 | 03:28 PM
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Hi Jay777,
Here is the link to just about everything on the HVAC system, including pressure charts which are quite different from the usual:
https://rennlist.com/forums/993-foru...diagnosis.html
Here is the link to just about everything on the HVAC system, including pressure charts which are quite different from the usual:
https://rennlist.com/forums/993-foru...diagnosis.html
06-19-2018 | 06:46 PM
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For some reason I spazzed out thinking refrigerant could only be added by a shop with the right equipment. Guess that was the old days. Anywho, went down to the local parts store and picked up a charging setup and some refrigerant and gave it a shot.
Pressure was so low that the 3 level pressure switch was kicking in. As soon as I added some R134, compressor kicked in as expected. Blowing cold now, and saved a trip to the shop.
BobbyT - awesome link, thanks. Those pressures ARE different. The instructions that came with the kit said 45-50psi for 85F ambient!!
Pressure was so low that the 3 level pressure switch was kicking in. As soon as I added some R134, compressor kicked in as expected. Blowing cold now, and saved a trip to the shop.
BobbyT - awesome link, thanks. Those pressures ARE different. The instructions that came with the kit said 45-50psi for 85F ambient!!
06-19-2018 | 11:26 PM
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The low side pressure should not be anywhere near 45-50, or even 35. At 86F ambient it should be at 9 to 17 PSI, yep, that low, unlike most cars out there. The total amount of R134A is 29 Oz.
06-20-2018 | 08:44 AM
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A number of YouTube videos show more elaborate procedures using rigs with high and low pressure guages and separate fill port. A vacuum pump is used to evacuate/leak test the system prior to adding any refrigerant. Probably the way to go where a leak is suspected, but I was in a bit of a hurry so just used the low-side rig and added. AC was working at the end of last season but bad this spring so probably a slow leak somewhere. Will soon find out.
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06-20-2018 | 11:35 AM
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”This is the biggie… incorrect refrigerant levels. A 993 uses very low system pressures at the compressor compared to “normal” cars. So the standard rule of thumb to simply “throw in a can of r-134” is very bad advice in a 993. Even if you are a little low on refrigerant. A full can – even a small can – will put your system way too high. You would be surprised how much even a little bit too much refrigerant can hurt your vent temperatures. This makes using the cheap gauges that come with refill kits poor for 993’s. If you do use those single/low side gauges, you can get a good idea of what your level is, but just use the chart above to make sure you have the right levels, and not the chart on the gauge itself. Again, working off of an 86 degree ambient temperature, you should only read 10 to 17 psi of low side pressure at 2000 rpm’s.”
”This is the biggie… incorrect refrigerant levels. A 993 uses very low system pressures at the compressor compared to “normal” cars. So the standard rule of thumb to simply “throw in a can of r-134” is very bad advice in a 993. Even if you are a little low on refrigerant. A full can – even a small can – will put your system way too high. You would be surprised how much even a little bit too much refrigerant can hurt your vent temperatures. This makes using the cheap gauges that come with refill kits poor for 993’s. If you do use those single/low side gauges, you can get a good idea of what your level is, but just use the chart above to make sure you have the right levels, and not the chart on the gauge itself. Again, working off of an 86 degree ambient temperature, you should only read 10 to 17 psi of low side pressure at 2000 rpm’s.”
06-20-2018 | 04:33 PM
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06-20-2018 | 05:04 PM
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Adding more refrigerant without using the correct procedures and equipment may get the system working again for a short while, but in the long term, might be harmful. I made this mistake a few years ago using something called "EZ Chill Measure and Charge Can with Inline Gauge" from my FLAPS (coincidentally also sold at WalMart). It purportedly contained a magic component, "Leak Sealer to seal most common leaks", which actually plugged up some important parts such as the expansion valve, and rendered the entire system ineffective and contaminated with the sealer goop. End result was replacing pretty much all of the system components, including the leaking evaporator, which was the initial problem.
06-21-2018 | 07:46 PM
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Here is a great thread on charging the a/c.
I noticed the numbers are at 2k RPM's, so keep that in mind.
https://rennlist.com/forums/993-foru...diagnosis.html
I noticed the numbers are at 2k RPM's, so keep that in mind.
https://rennlist.com/forums/993-foru...diagnosis.html