Had my air converted to R134 and...

[smoak]

Well this was a mistake. My front blower fan had to be replaced and I said go ahead and convert the air. Now my air barely gets cool (actually used to get COLD coming out of the garage) and Im out a bunch of money. Is the R134 freon just not as good or what? Im sure I can just give up on getting in the car after its been sitting in the sun for some time, which I know sounds like a little baby but the "feels like" tempature here in Tampa, Florida is like 104 on a daily basis and this car is my daily driver. WHAT HAVE I DONE and WHAT CAN I DO NOW?

[ruf-porsche]

It could be that the system is over filled. You need to know the low and high side pressure and at what ambient temperature these readings were taken.

When replacing R12 with R134a you don't put the same amount of refrigerant back into the system, it's about 80% of what R12 is so if your system for R12 was 40oz than r134a should be around 32 oz.

Bring the car back to whoever did the conversion and have them fix it correctly.

If they put R134a in the system base on the bubbles in the sight glass of the receiver/drier that is the problem, you don't use the sight glass when you use R134a.

[724doorE]

I don't think the r134 is as efficient (simple terms)a fluid as the r12 (thats why they used r12 in the first place.) I don't recall sitting in any new cars that had that "freeze you out AC" of the old R12 days.

You might make sure they did the job correctly, It seems that different people claim different things need to be changed. I belive you need a different evaporator valve at least, but I don't be no espert, I just know how the system cycle is supposed to work.

[ruf-porsche]

All the new cars that are produce and sold in the USA has 134a as the refrigerant. I have driven in some car that will freeze you out like the old R12 system, but all the cars that I have driven with R134a as a refrigerant is capable of cooling on a hot summer day. Granted the system was design for the new refrigerant, but it still use the old fluid mechanic principles.

[Sunroof]

After replacing all my lines and drier last summer I had the AC guys put in R134. The first round of recharging with R12 blew an old hose and a bunch of $$$$$. After the replacement, I never wanted to spend big bucks on R12 again.

The R134 has done well for me here in this Atlanta heat thus far. Maybe its becuase the AC folks advised to not overcharge which may have happened in your case. My front condenser fan went out too, so that makes it more interesting.

R12 compared to R134 is not that significant when it comes to cooling. Something is going on that you need to re-check.

Regards
Bob
73.5T

[JeremyD]

Hey Smoak - Craig Stevens had some AC work done in the area - do a search and PM him - he was talking to me about it at the Starbucks get together. I think he had a underbelly condenser added too - said it made a world of difference. Mine still has the R12 - and stock system - but I don't use it as a daily driver. It's still OK - But sitting out in the sun all day can be a real challenge.

There is also a great article in Excellence this month (got it yesterday) that has a 88 cab in Florida going through an AC upgrade with components from griffiths... Anyway - wish I could be more help - who converted your AC? They should be able to fix if you are not happy.

[jmohn]

Originally posted by smoak
Well this was a mistake. My front blower fan had to be replaced and I said go ahead and convert the air. Now my air barely gets cool (actually used to get COLD coming out of the garage) and Im out a bunch of money. Is the R134 freon just not as good or what? Im sure I can just give up on getting in the car after its been sitting in the sun for some time, which I know sounds like a little baby but the "feels like" tempature here in Tampa, Florida is like 104 on a daily basis and this car is my daily driver. WHAT HAVE I DONE and WHAT CAN I DO NOW?

Assuming the system is actually functioning correctly, you almost certainly are either over or under charged (probably over-charged). I'm not a fan of 134a, but it will work if correctly installed; it is much more sensitive to minor changes in the charging of the system than R12, even slight over-filling with 134a will drastically reduce it's cooling ability. 134a is slightly less efficient than R12, but it should still get cold (e.g. if you were seeing 44 degrees at the vents with R12 you should get 46-50 degrees with 134a).

Jerry M
'78 SC

[smoak]

Joe at German Tech did the air for me. I really thought he made it sounds like a good idea. Well it was not, to say the least. I told him that the old system didnt work well in the sun. He suggested the new system. The new system never even got COLD this morning on the way to work. GRRRRRRR. I will look to the Excellence for suggestions.

[RickC]

I remember hearing in the mid 1990's when they converted to R134a that cars had to have larger A/C systems since it was not as efficient as R12. Don't know the percentage difference, but might want to dig a little bit on this. Don't know enough about A/C to speak much further, but this might mean needing a larger cooling surface???

[JeremyD]

I'd take it back to Joe - He switched the AC on my C2 Targa to 134a and it worked fine. He'll make it right... or at least as good as possible - I'd check with Craig too though - I mean I have R12 in mine -It's 100% stock - but blows cold in the vents. The cab just looses too much through the top - and the top get's way hot! In the mornings I can get to work in a shirt and tie without sweating. In the afternoons - it just takes too long to cool.

My personal opinion is that the only way you will be satisfied with the AC in your car is if you upgrade it - either underbelly condenser, new dryer and compressor, etc. Even with the AC in my Targa (964) which is considered a superior system - I was reluctant to use it on the steamy days (which we have had a bunch of!)

[Jim Sims]

To get the most out of R-134a conversion: (1) internally flush all condensers and the evaporator if possible. One can mail order an aerosol can of flush complete with the nozzle and hose for $13 that does this very well. There was no excuse for not doing this to the evaporator if it was out for a blower repair. Remove the expansion valve before flushing the evaporator. The reason flushing is important is that the mineral oil used in R-12 systems is not miscible with R-134a. It gets stuck in the condensers and evaporators coating the inside of the heat exchange surfaces and impeding heat transfer and hence cooling. Whenever possible disconnect lines and drain any low spots of mineral oil. Also, externally flush the the air side of the condensers and evaporators. The evaporators tend to get clogged up with dirt, mold and lint on the air side. (2) Change out the receiver/drier (it traps oil too). (3) If any of the hoses are bad, change to barrier type hose with o-ring bubble crimp type fittings where ever possible. (4) Change any line fitting o-rings to the R-134a compatible type (usually colored green). (5) Drain the compressor of the mineral oil and install the appropiate amount of new oil (usually ester type in a R-134a conversion). (6) Install a high pressure cutout switch between the compressor and the first condenser. (7) Pump down the system for at least two hours with the car sitting in the sun. (8) Refill using a refrigeration harness with R-134a calibrated gages; checking high and low pressures. The sight glass method cannot be used with R-134a. Do not overcharge!

I brought my 1976 vintage A/C system back to life doing a conversion to R-134a. It is a new and pleasant experience riding around with the windows up and it being 100F outside.

Cheers, Jim

[NYNA 11]

Smoak,
Need the air temperature blowing out the vent and the outdoor temperature so we can get an idea how bad it is. My 134a system is fine, in my 87.
Ned

[nostatic]

From all I've read here (and it is quite a bit...there are a ton of threads on AC), you can't just toss in R134a and go on your merry way. Read Jim's response. If you want to convert to 134a and have it work, you need to replace parts. In fact, some will tell you have have to replace not only the receiver/dryer and expansion valve, but also the compressor (especially if you have the original York) and the 40' of hoses, upgrading to "barrier" hoses.

I should see today how a halfway effort goes...I'm replacing compressor, receiver/dryer and expansion valve, and will likely charge the system with Freeze12. Depends what the wrench thinks is best.

[88911coupe]

Well I'll add one more commment herel, FWIW. The PO of my '87 Cab converted the car to R134 and it worked "almost" as good as my '88 with R12 does now. I was on the highway in Oklahoma when the ambient temp at 3:30 pm was 106 and the car was comfortable...not freezing, but comfortable. I suspect something's amiss in your car.
Good Luck,

[ruf-porsche]

Originally posted by Jim Sims
(7) Pump down the system for at least two hours with the car sitting in the sun.
Cheers, Jim

Hey Jim

Never heard of this one, why do you need to pump down the system with the car sitting in the sun and do most a/c shop do this? Most a/c shop have the car sitting in a service bay under a roof when they service the a/c.

[Jim Sims]

Heat helps mobilize any water within the system and move it through the hoses to the vacuum pump. The lower the pressure (higher vacuum) and the warmer the system, the more water one will remove. Letting the car sit in the sun is an easy way to warm up the system during evacuation. Cheers, Jim

[ruf-porsche]

Thanks for the info Jim.

[nostatic]

when you pull a vacuum to remove water, the temperature of the components in the system drop in temperature (PV=nRT, drop in P makes for a drop in T). The temp drop makes it harder for the residual water in the system to vaporize and be removed.

Come to think of it though, do AC shops use a trap on the pump system? We always had either simple or elaborate traps on our vac systems in the lab. Then again we were often pulling nasty solvents off instead of just water, but even water would make high-vac pumps pretty unhappy.

[JeremyD]

I'd be interested to hear how yours goes nostatic... Are you doing the underbelly condenser? I hear that or the drivers's side aux condenser can have the biggest impact... That and the compressor. It's been hell hot here the past week. Even the AC on my house went out yesterday.

[nostatic]

Everything else is staying stock until I see how this goes. Luckily we don't have too high humidity around here, and I'm not looking for ice cubes, but a bit of cool breeze to take the edge off.

Funny thing is I never had a vehicle with AC until I got my short-lived Mazda PU in '94 (at the ripe age of 32). 6 years living in pasadena with no AC at all...car or house.