there's a/c in those cars???

LOL http://www.pelicanparts.com/support/smileys/burn.gif

88 911
53 degrees from vent
90 degrees outside
Bone stock system
R134

87 911
40 degrees from side vent
50 degrees sitting in traffic or slow speed travel
95 degrees outside
Bone stock system
R134

Recently replaced all orings, expansion valve and dryer. Replaced front seal and orings in Nippodenso compressor. Cleaned out evaporator and sealed smugglers box intake and outlet. Sealed all air distribution hose connections under dash and fwd bulkhead. Pumped system down to 27 in-Hg, ran vac pump for three hours. Left system under vac for one week and measured 27 in-Hg vac, verifying no leaks. Ran vac pump an additional hour. Charged system with 32 ozs of Dupont Suva R134. High pressure about 230 psi and low pressure 20 psi and 90 deg. Measured as low as 35 degrees out of bulkhead vent and consistently measure 40~42 deg during normal driving.

BTW, Thanks to Jim Sims, Scottb and Thomas Owen for their input during my A/C resurrection project.

85 Targa, stock system w/ Procooler, 134. High 30's with ambient in high 80's low 90's.

I recharged mine last year with Duracool and was in the mid 40's in the shade in high 80 ambient temp. With a Cab, not a big issue, just like to have everything working just in case!

74 911
rear condenser only
R12
blows 50-55

and 50-55 does NOT keep it cool when the sun is shining brightly on a 90 degree Atlanta day

G

whoops. double post.

brcorp, do you have any photos or tips for someone trying to follow roughly the same procedure?

Anyone have a good supplier of barrier hose or a barrier hose kit, with some good instructions?

Thanks.

www.ackits.com, talk to Jack if you call them. All new barrier lines with new fittings, O-rings and oil for $120 shipped.

Sorry, no pictures. This is actually a fairly easy DIY project though. Don't waste your money on barrier hose. Replace all 12 orings, they're fairly easy to get to. 2 @ the compressor, 2 @ rear condensor, 2 @ front condensor, 2 @ dryer, and 4 @ expansion valve / evaporator. Use two wrenches on the fittings or be prepared for problems. Use the new style green orings, not the black. The green compound is compatible with R-134 and R-12. Remove the evaporator assy from the smugglers box, clean, install new expansion valve, reseal air inlets. Search for threads on this topic. Install dryer last. Add 2 oz of compressor oil (BAV Auto 100, 2 Ounce Bottle - compatible with R134 and R12) directly to the dryer prior to install. Twist the hose from the evaporator a bit to get the dryer to fit.

All of this if fairly straight forward, the real trick comes in a complete evacuation of the system and verifying there are no leaks. All water in the system needs to be boiled off so don't rush here. Pull a vacuum for at least three hours. Cheap vac pumps are available at Harbor Freight, you'll need a compressor though. Then let the car sit, under vacuum, pump disconnected, gauges connected, for a couple of hours and verify no loss of vacuum. If there are no leaks let the car sit, under vacuum, gauges/pump disconnected for a couple of days (I let it sit for a week), then reconnect gauges and verify no loss of vacuum. This is probably over kill, but I have low vent temps, low head pressures, stock system, and R-134. Connect pump, pull vac for one hour then charge with R-134. Take your time when charging and don't spray water on the condensers as you'll get artificially low head pressures.

Don't use a sealer R-12 or R-134 as it will clog your system, if you have leaks fix'em.

Get your dryer and expansion valve from Mike Norris @
http://www.ackits.com/

Any more questions?

how cold is it outside?

Right now it is about 84 deg, when I charged and checked head pressures and vent temps it was 95 deg, low humidity, car was in the sun, about 3:00 pm on a Saturday. I was wearing shorts and a tee shirt....

How are you charging the Duracool? Gauges, weight, line feels like sweaty beer can?

Jürgen

That's what this board is all about. I'm glad you're happy with the results. SmileWavy

Now if I can only talk you into a ride in the BELL....

If you're ever in LA, let me know. :D

I'll bring a couple of Paveways and an AIM 9X or two and we'll have a good time....

Br, that's actually the first time I've heard that the hoses are decent -- everyone points to "40 feet worth of 14 year-old hoses running through the car" as the primary source of coolant loss, and hence a/c inefficiency. You're saying that the hoses are not the problem, but the O-rings are? I'd be curious to hear your thoughts, as well as others. I plan to do something about the A/C pretty soon.

Thanks again for the nots, pointers, and ideas.

Jared

The hoses are a source of A/C inefficiency only if they are leaking a sufficient amount to significantly impact the performance of the A/C system. The leakage rate of barrier vs non-barrier hoses is on a microscopic level, for hoses that are structurally sound this amount could be considered insignificant over a short period of time, such a 6~8 months.

My position/experience on the A/C system is based on being able to evacuate/refill the system and test the effects of additions of small amounts of R-134 (1~2 oz) and gauge the system performance accordingly.

Here is a quote from ScottB (A/C Evacuation thread) that sums up the hose issue:

"The factory hoses were designed to leak. That's why the a/c systems don't hold a charge for more than a season or two. (I've heard that the molecular structure of R134 is smaller than that of R12, and that it leaks through non-barrier hoses faster than R12). With the skyrocketing cost of R12, you want barrier hoses to retain the R12 within the system, with no leaks. If you're going with R134, you can retain the original, non-barrier, hoses for two reasons. First, R134 will not harm the ozone like R12. Second, you can buy R134 at your local AutoZone and top-off your system on a DIY basis. Thus, leaks are an annoyance, but nothing more. R12 requires an (easily obtained) EPA license."

12 oz R-12 ~ $35.00 12 oz R-134 ~ $6.50

The cost of new hoses is about $200.00, assuming you send out for them (AZ Mobile Air) and reuse your old fittings. Add to that the install hassle. It is DIY project, but I feel your money can be better spent else where (premuff or dual outlet Dansk). Now this assumes your existing hoses are in good condition. You may only consider replacing the hoses off the rear condenser as they may be fatigued due to opening/closing of the deck lid plus engine compartment thermal effects. This is where the vacuum / leak test comes into play, as my system held vacuum for a week (no shop would be winning to do this) I felt confident in not replacing my hoses.

Regarding the o-rings, it is very likely that 14 year old o-rings are brittle, deteriorated, cracked, etc. O-rings should be replaced with either NBR or HNBR replacements.

My 100th post, I'm so excited :D

And another thing.

Evacuation, recharge and topping off are very easy. A little education and attention to detail is all that is needed to add this to the list of DIY accomplishments. For less than the cost of a "professional" job, you can do it yourself and have a set of gauges ($35.0 on EBay) and a vacuum pump to show for it.

Most important thing is being able to identify the high pressure (discharge side - goes to condenser) and low press (suction side - returns from evaporator) lines. Second, never charge in liquid (don't turn can upside down when charging) always charge gas on the low pressure side. Third, wear safety glasses, don't worry you'll make them look cool. Fourth, don’t over charge! Finally, don't forget to add a hi/low pressure cut off switch.