Time/Labor estimate for AC seal replacement

[Highway Q45]

Has anyone done the AC seal replacement (not-compressor seals) for a Gen1 Q? If so, how long did it take and which ones are the hardest to get to. A local shop still can't find a very slow leak even with UV dye. The system holds the specified vacumn for 30+ min but slowly leaks R-12 Freon over a 2-3 month period. I'm tired of topping off this often and hope the seals will help extend the refill interval. I still have a good supplier for R-12 in the 12 oz. cans.

I have no intention of converting to R-134, my wife drives it mostly in local traffic where the efficiency of 134 goes way down.

[911/Q45]

Are you talking about the orings? they are at every spot that a line connects to hardware. I think there are 8, 2 each for compressor, condensor, evaporator and drier. I would replace all if you're going to do it. The compressor and evap are probably the toughies.

[DAEDALUS]

That shop that can't find the leak better not be an AC shop. A good sniffer is not expensive. Most likely it's a seal near the evaporator if they can't find the leak, or maybe even a tiny puncture in the condenser. Just FYI I've checked several friends' cars. Haven't found one yet that doesn't have at least a tiny leak on it, even among newer cars.I've replaced the seals on the lines going to the compressor and the drier. Easy enough. It's getting to the ones you can't see that would be the problem, in addition to recovering and vacuuming out the system.

[Highway Q45]

I'm thinking a pinhole myself although the connection near the evap unit is hard to reach with a gas detector. An evaporator leak on the fins would vent internally wouldn't it? I think the shop tried both dye and sniffer but I doubt if they ran them over anything but fittings. I've had the 8 O-rings from Joe for months but have been too tied up with the P-cars. Time to dive into the Q again and I still need to fix that HVAC panel. I'll try the ghetto home solder fix first; if that fails I'll send it to San Diego for the $100 fix. I would estimate the leak rate is about 2 oz per 90 days of use; maybe that's normal leakage considering it's age. I'll replace the easy seals, tighten the others, and see if the leak rate goes down at all.

[Q45tech]

Hoses? Common after they are 7 years old!

Base on EPA report 90-93 R12 systems lost up to 0.4 Kg per year or 14 ounces per year thru hoses.http://arch.rivm.nl/env/int/ip...2.pdf

Your 2 ounces per 90 days = 8 ounces per year.........almost half the average old hose leakage rate.

New flex hoses should reduce it further.

My Q needed topping off about every 2-3 years..........in 2000 I changed the hoses to the newer improved versions and now get by with annual recharges in May........usually on need 4-5 ounces now.

Most owners didn't notice [ignorance] of the slow degradation till it became excessive.........usually at around 40% [0.9 pound loss]

I monitor the system [temperature differential] quite closely especially with the oem evaporator being 14.5 years old.

Are you filling EXACTLY to 2.4 pounds [1.1 Kg].

The hour I spend each year [in early May] to optimize AC is well worth it..........vacuuming out 2 ounces of oil and replacing it.

[Highway Q45]

Hoses? Common after they are 7 years old!

Your 2 ounces per 90 days = 8 ounces per year.........almost half the average old hose leakage rate.

That's good to know!

New flex hoses should reduce it further.My Q needed topping off about every 2-3 years..........in 2000 I changed the hoses to the newer improved versions and now get by with annual recharges in May........usually on need 4-5 ounces now.

Thanks Dennis. Are the improved version hoses actually just later model hoses for R-134 with the improved liners for higher pressure service? Sounds like a good idea to upgrade the hoses, any ballpark idea what they cost for a Gen1?

Most owners didn't notice [ignorance] of the slow degradation till it became excessive.........usually at around 40% [0.9 pound loss]

I monitor the system [temperature differential] quite closely especially with the oem evaporator being 14.5 years old.

Are you filling EXACTLY to 2.4 pounds [1.1 Kg].

Sorry, I've never vacced and weighed the charge, I just add a bit at a time and watch outlet temps and HP side pressure on the manifold gauge. So you vac every year and refill by weight? I don't have a recovery unit so I'm limited to what I'm capable of doing as a home mechanic. Sounds like having it done right at a shop at least the 1st time would be worth the effort...I doubt if I could do it every year though. Right now I assume my system is empty or has whatever minimal charge remains after the low pressure switch kicks out the compressor.

The hour I spend each year [in early May] to optimize AC is well worth it..........vacuuming out 2 ounces of oil and replacing it.

[Q45tech]

Annual R12 AC check and service just one of the many things uneducated owners SKIP.........because it's not in the owners manual.

Tolerating the slow decline, till finally the system doesn't cool then they get the $2,000 parts replacement bill and a partial repair.

The Q hoses are a notch above average hoses but they all leak and flake off and degrade from the inside.

You are lucky you have a cheap source of R12.

The pressure method works but you are probably under filling the reserve amount that's why you weigh to extend the time between feeling the decline.

Too little oil [8.2 ounces total] and the compresssor life is reduced, too much oil and the temperature is higher than optimum.

How often do you change your receiver dryer [every 60,000 miles]

[Highway Q45]

Annual R12 AC check and service just one of the many things uneducated owners SKIP.........because it's not in the owners manual.

You are lucky you have a cheap source of R12.

How often do you change your receiver dryer [every 60,000 miles]

Yes cheap R-12 is a real plus; I have a friend that goes down to San Felipe in Baja every spring and brings me back a case of 6 cans. Reciever/dryer was replaced by PO at 90K, 3 years ago. Since the system is low, I'll be changing the R/D out with the seals and probably do a condenser flush at the same time just for good measure. Thanks again for the heads up on the new hoses.