A/C Questions After Reading All A/C Threads

[jdbs3]

1990 Vanagon GL, ~110,000 miles

I am the second owner of this van and am getting it ready for a long road trip. In the 7 years I have owned it, I never used the A/C. This year I will. I’m not sure how much the original owner used the A/C. When I took the evaporator housing down (now its back up) it looked very clean.

I’ve read the Bentley Manual, every note I could find on this and other forums, and many of the notes on www.autoacforum.com. I have a few basic questions:

1. I will take the van to my mechanic to have the R12 discharged, and to do a leak test. If there are no leaks in the current system, then is it still advisable to change the receiver/dryer? To still blow the snot out of the system?

2. Everything I have read in the forum says I must pull a hard vacuum on the system prior to adding the Red Tek refrigerant. However, the Red Tek site states in step 12a. “Refrigerant is installed through the LOW SIDE SERVICE PORT AND IS CHARGED AS A LIQUID INTO A “0” ATMOSPHERIC CONDITION. DO NOT INSTALL INTO A SYSTEM WHERE A HARD VACUUM EXISTS.” So which is correct?

3. Somewhere I read you should only fill the system to 80% of its capacity. Is this also true for Red Tek?

4. Where is the A/C refrigerant low pressure switch? Page 87.6 of the Bentley Manual shows the high and low pressure switches as separate switches, however, my van only has a single switch that sits above the high pressure valve under the left rear panel? Was the high and low pressure switch combined into a single switch at some point?

5. I will most likely install a new receiver/dryer after blowing the snot out of the lines. When blowing the snot out of the A/C lines, is it ok to leave the lines connected to the other A/C components (i.e. condenser, the *old* receiver/dryer, expansion valve, evaporator housing), or should I first detach them from these other components?

6. In changing the compressor oil, can I just remove the old oil and add new oil, or do I need to flush the compressor with the new oil before refilling the compressor?

7. And can I avoid removing the compressor to change/flush the compressor oil? This would sure make life easier.

thanks!

[scottjk]

I saw your post and did some digging around.

http://www.thecomputermechanics.com/forums/showthread.php?t=35955

I'm in the same boat but it doesn't sound like Red Tek is the way to go. Has anyone else used this stuff?

Thanks

Scott

[James 93SLC]

Those are some great questions and I'm looking forward to some of the answers you should get.
There are a several on here that are big fans of the Redtek, so I'm curious to see responses.

[markz2004]

I'd like to know WHY they recommend not to use it. Seems to work well for so many.
_________________
87 Westy, 250k GW 2.4 - 2.0 , 16" wheels

[trip'n]

jdbs3......sounds like we have almost the same van and looking for the same a/c fix......from what ive read and searched on redtek....it seems to be the way for the vanagons...and a new dryer

Ken
Master Auto Mechanic
&...................................i dont know theses guys....
JPolito830
Apprentice Mechanic
from computermechanics ...and there vanagon knowledge

i wait for the o gr8t............... gu......roooos....to speak
ommmmmmmmmmm...ommmmmmmmmmm...ommmmmmmmmmmmm

[funagon]

Do you really believe those guys on the other forum who are bad mouthing Red Tek? There's only two responses on that forum. The first guy says that Redtek is "junk" and will "ruin your system." These claims are hyperbole, unsupported by explanation or example. The other guy says "my buddy told me not to use it." Contrast their opinions with the many satisfied users on the samba who have detailed how they installed the redtek and how well it continues to work for them.

I first tried 134 because a trusted auto shop told me that redtek was "junk" and would "ruin my system." They did a professional clean and recharge of my van's system and the results were terrible. Would not get cold, worked my compressor too hard so that it was robbing the engine of power, and as we all know 134 leaks out and requires a recharge every year. I installed the redtek myself and now I have cold air, my van's compressor does not rob the engine of nearly as much power, and after two years it has not leaked out, I haven't recharged it or done anything to my A/C system, and I still have cold a/c in the summer heat.

Do I have any complaints? My a/c is not ice cold when the car is idling or in stop and go traffic. But when the van is moving (a constant flow of air over the condensor) it takes five to ten minutes to get really cold, and then gets so cold that I have to turn it down because I get a chill. I've driven across the Nevada and Utah deserts in 100 degree heat, cold as a popsicle with the a/c on in my van.

As for your list of questions, I can't answer them because I'm definitely not an a/c expert. I didn't clean out my lines or anything before installing the redtek. But as for the compressor, I think you have to remove it and dump the old oil out then add in the new. I replaced my compressor and reciever-dryer, so maybe that's one reason my system works well?
_________________
1990 GL 7-passenger
2.2 liter WBX

[agreendaya]

I'm intrigued, and thus have commented so my email machine will tell me when others reply to this thread.
I want AC too, mine still needs to be converted from R-12 I believe, sure doesn't work now...I take it something bad happens if you just try to refill it with this redtek stuff or 134 without doing something first....?
_________________
'74 Bug - Gone
'69 Westy - Gone
'74 Westy - Gone
'78 Transporter - Gone
'69 Baja - Gone
'91 Vanagon Carat - Gone
‘71 Bus - Gone

Current: ‘74 Westy 2.0L, hydraulic valves, dual EMPI 34s

[xlr8r]

For me, anything to do with the A/C is not a do-it-yourself job.
Anyone have a recomendation for a shop in the Seattle area that does Red Tek?
_________________
1991- Seven passenger with 3.3 SVX ; 1987 - Seven Passenger with 2.5 Subaru

[Terry Kay]

<< When I took the evaporator housing down (now its back up) it looked very clean.>>

Even though it "looked " clean , did you blow the evaporator out anyway?
What did you do with the black foam rubber that has covered it?
Removed it all I hope.



<<1. I will take the van to my mechanic to have the R12 discharged, and to do a leak test. If there are no leaks in the current system, then is it still advisable to change the receiver/dryer? >>

110,000 miles, 22 years old, it would be a real good idea to install a new dryer.

<<To still blow the snot out of the system?>>

A real good one.
prior to installing the new dryer.

<<2. Everything I have read in the forum says I must pull a hard vacuum on the system prior to adding the Red Tek refrigerant. However, the Red Tek site states in step 12a. “Refrigerant is installed through the LOW SIDE SERVICE PORT AND IS CHARGED AS A LIQUID INTO A “0” ATMOSPHERIC CONDITION. DO NOT INSTALL INTO A SYSTEM WHERE A HARD VACUUM EXISTS.” So which is correct?>>

Your going to have to pull a hard vacuum to find out if the system is tight, and remove all the moisture that may be in it.
How do you plan on getting the Red-Tek into the system--release the vacuum?

Bad idea.

stick it in there with the vacuum--you'll be glad you did.



<<3. Somewhere I read you should only fill the system to 80% of its capacity. Is this also true for Red Tek?>>

Fill the syetm until the operating pressure's are correct.

<<4. Where is the A/C refrigerant low pressure switch? Page 87.6 of the Bentley Manual shows the high and low pressure switches as separate switches, however, my van only has a single switch that sits above the high pressure valve under the left rear panel? Was the high and low pressure switch combined into a single switch at some point?>>

Later model Vanagon's have the low & high pressure switches right next to each other behind the L/H rear plastic panel.
On earlier models, the low pressure switch is on the back of the compressor.


<<5. I will most likely install a new receiver/dryer after blowing the snot out of the lines. When blowing the snot out of the A/C lines, is it ok to leave the lines connected to the other A/C components (i.e. condenser, the *old* receiver/dryer, expansion valve, evaporator housing), or should I first detach them from these other components?>>

Leave everything connected.

<<6. In changing the compressor oil, can I just remove the old oil and add new oil, or do I need to flush the compressor with the new oil before refilling the compressor?>>

Drain & re-fill

<<7. And can I avoid removing the compressor to change/flush the compressor oil? This would sure make life easier.>>

Nope.

I don't know how you plan on completly get all of the old oil outa the compresor & re-filling it with it mounted to the engine
_________________
T.K.

[VisPacem]

[scottjk]

Ok, so I'm going to go for Red Tek. The van is at the shop for a different problem but I'm going to have him pull a vacuum on the A/C system while it is there.

I'm curious as to whether the Harbor Freight vacuum is good enough to do an effective job. Does anyone have experience with these?

Thanks

Scott

[Terry Kay]

Scott,

I had thought from the title of this thread you had read all of the other posts regarding the AC & Red Tek subject.

ANY Time you have the system open, you must evacuate it.

So, with this in mind I would first get the compressor off & change the oil.

While you have the hoses off the back of the compressor, flush out the system.
It would be a real smart move to remove the dryer and make a jumper hose/ pipe to eliminate any garbage that may be in the dryer.

Then, once you have the system all cleaned out, install the new dryer, and THEN have the system evacuated.

It sounds like you might have to do some reading prior to jumping into this, on some basic AC operation & theory.

IF you don't wanna do that, I'd back up and do some subject searhing here again before you jump into your AC system butt naked.
It might be a real good idea to get to know what you should expect from a refrigerant system & it's components prior to getting into this job.
_________________
T.K.

[morymob]

If the vac pump u are using will pull 28in vac u will be ok.

[James 93SLC]

Terry - I think the OP knows the "proper way" is with a vacuum. He was just noting that RedTek's instructions say not a "hard vacuum" and was hoping someone might have an idea why they say that. I must say that is a curious statement on RedTeks part.

Now on to the claims of RedTek being "junk". I did a search on that forum posted earlier with the so called "experts" and the biggest issue I read about had to do with RedTek being a HC (hydrocarbon gas), and that it is a blend of gases (propane being one of them). The experts claim that some of these blended gases have properties that allow them to seep through rubber lines over time, and this leads to an imbalance in the system (leaving the other gases to do the work). The other issue is flammability, which I agree with Terry as being a minor issue in the grand scheme.

Terry - Would you advocate flushing each line, the condenser, and evaporator individually as a 100% sure fire method of flushing the system?

[James 93SLC]

[scottjk]

Can someone post some definitive links and brand names for this "air brake flushing" fluid?

I purchased a Robinair 15600 A/C pump. If anyone is in the Salt Lake area and would like to use it I will make it available for a small donation to help recover the high cost.

Thanks

Scott

[scottjk]

Have we come to a definitive conclusion about whether it's o.k. to use both the Proseal and Leak Stop at the same time? I just got off the phone with Red Tek and the guy told me to use both but I remember reading somewhere that it wasn't a good idea.

Thanks

Scott

[Terry Kay]

<<But what happens over the long term?..

How long of a term do ya want James?

I've had it in my Vanagons for at least 10 years,the Mack trucks & Cats at work for 12.
I installed it in my buddy in Ky's Farmall 1586 back in 1994.

I had to suck that down recharge it once when it blew a belt and bleep hole in the low pressure hose.
_________________
T.K.

[Terry Kay]

<<Can someone post some definitive links>>

The local yellow pages;
Mack Truck, Volvo, GMC, White, Petrbuilt, Kenworth,Ford, Sterling, Freightliner,Mercedes Benz, Hino, or Mitsubishi, Parts dealer's or any Truck stop.

<< and brand names for this "air brake flushing" fluid?>>

Bendix air dryer alcohol would be good for starter's.
_________________
T.K.

[Terry Kay]

<< I think the OP knows the "proper way" is with a vacuum. He was just noting that RedTek's instructions say not a "hard vacuum" and was hoping someone might have an idea why they say that. I must say that is a curious statement on RedTeks part.>>

It's a real simple answer James.
If the sytem just lost it's charge--you don't have to suck it down.
If you are opening it up to remove & replace component's, clean out the line's & parts,--Make it a habit to evacuate the system.

<<Now on to the claims of RedTek being "junk". I did a search on that forum posted earlier with the so called "experts" and the biggest issue I read about had to do with RedTek being a HC (hydrocarbon gas), and that it is a blend of gases (propane being one of them). The experts claim that some of these blended gases have properties that allow them to seep through rubber lines over time, and this leads to an imbalance in the system (leaving the other gases to do the work). The other issue is flammability, which I agree with Terry as being a minor issue in the grand scheme.>>

The politcally unstable Krew over at the Vanagon.com list argued with me on this for years.

Forgive them for they know not what in the heck they are talking about-and neither do the other mad me on this list your refering to.

They imagine fire & brimstone blowing outa the AC vents.

Well, It just ain't gonna happen that way.

Get your fat butts offa the 18 gallons of gas your sitting on Louie--

That's something to be worrying about.

<<Terry - Would you advocate flushing each line, the condenser, and evaporator individually as a 100% sure fire method of flushing the system?>>

Nupe.

I remove the lines at the compressor, drop the BENDIX air line dryer in each hose individually, and blow it clean.
Repeat the process in the opposite hose,till it's contents look clean as it's spewing it on your clean white T-shirt.

No big deal-not complicated, quick, easy, simple, and complete.

Your done--charge her up Johnny---
_________________
T.K.