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convert 93 S10 to R134a, trying to DIY

rastoma on Thu June 17, 2010 6:05 PM User is offline

Year: 93
Make: Cheverolet
Model: S10 Blazer 4x4
Engine Size: 4.3 (W)
Refrigerant Type: R134a
Country of Origin: United States

I have a 93 S10 Blazer, 96k miles (not 196k), 4.3 V6 (W) engine, 4x4.

I have only had it about 10 months. The a/c didn't work when I got it. The compressor would cycle on and off like it was low on coolant. No difference in air temperature obviously while on. It had not been retrofitted so it had R12.

I haven't tried working on it until recently. I got a professional a/c gauge from Autozone (free loaner) to test the pressure level to see if in fact it was just low coolant. Well, maybe it wasn't something I should have tried to do since I had never measured coolant pressure before but I figured that it couldn't be difficult just to snap on some gauges and read them. The gauges were setup for R134a and came with adapters for the gauges so they could be hooked up to R12 ports. Well they were crap because they 'hooked' on but I didn't know until AFTERWARDS that rubber o-rings were missing from inside the connectors. So all the R12 came spewing out and the ends were 'locked' on and wouldn't come off easily.

I wanted to give that background to let you know that I think all the R12 is now out...... UNINTENTIONALLY.

The compressor stopped cycling after that and didn't kick on at all due to low/no coolant of course.

I bought a retrofit charging system made by Interdynamics. 3 cans of air/oil and a trigger gauge with screw-on retrofit connectors. The compressor started cycling on and off after the first can which was good news. After most of the second car, the compressor stayed engaged. It took the second can and part of the 3rd can (kit came with 3 cans) when the psi got to 45 while the compressor was engaged. I haven't measured air temp but it's just not very cool. It is cooler than outside temp. but no where it's supposed to be.

So, after more research I realize at least the system needs to be vacuumed (should have been done first). I know someone who has gauges and a pump (he does residential a/c work mostly) and I can also rent the items.

I use this vehicle to deliver mail part time so I don't need the air often (since all the windows are down most of the time while delivering) and with the abuse it gets and the age, I won't have this vehicle for several years down the road. I know cutting corners will be frowned on around here but I hope I can find a happy median.

I will replace the accumulator and I'm sure the orifice tube needs to be replaced. The clutch makes no abnormal noise and hasn't ran in years up 'till what I did above a couple of days ago. So I'm hoping the entire system doesn't need to be flushed.

Can just the compressor be cleaned easily without special equipment?

Do I have to replace all the o-rings if there's no leaks? If I do need to, are there special tools needed to remove the hoses/tubes in order to replace the o-rings?

At ackits.com website for vehicle specific components, they do not list a R134a cycle switch but I know Napa has a R134a specific for this car. Do I need a switch that's labeled for R134a? I know ackits.com has an adjustable one but I need everything to be as plug and play as possible.

When replacing the orifice tube does it need to be done while the system is empty of refrigerant or can it be replaced at any time? I know when replacing the accumulator it will be empty but I'm just curious if it can be done.

Thanks.

Edited: Thu June 17, 2010 at 6:09 PM by rastoma

bohica2xo on Thu June 17, 2010 9:59 PM User is offline

Wow, you were a couple of parts away from a running system - until that death kit went into the system.

Now you get to go back to square one. Break the system down, flush, new O rings, etc.

The condensor & evaporator need to be flush to bare metal. The lines need to be flushed as well, unless there is a muffler built into one of the lines. That type of line should be replaced.

The compressor needs to be flushed with the same type of oil you plan to run in the system. Fresh oil is put into the suction port, and the shaft is rotated by hand to force the oil through the compressor. There is a thread for this in the procedure forum.

All of the seals should be changed to 134a compatible seals if you convert.

B.

-------------------------
"Among the many misdeeds of the British rule in India, history will look upon the act of depriving a whole nation of arms, as the blackest."
~ Mahatma Gandhi, Gandhi, An Autobiography, M. K. Gandhi, page 446.

rastoma on Fri June 18, 2010 12:24 AM User is offline

Quote
Originally posted by: bohica2xo
Wow, you were a couple of parts away from a running system - until that death kit went into the system.


Please explain how it has made things worse by using the kit.

Quote
Originally posted by: bohica2xo

Now you get to go back to square one. Break the system down, flush, new O rings, etc.



Yes. And that is the same thing that must be done on every R134a conversion from what I have since learned reading through this forum. So how is that different than if I hadn't used the conversion kit?


Quote
Originally posted by: bohica2xo
All of the seals should be changed to 134a compatible seals if you convert.
B.

So I'm still confused how I made things worse using the conversion kit because for a 'good' conversion everything has to be broken down and seals replaced, no?

I believe I pointed out that I NOW realize what needed to be done and have several questions that I was hoping to get help with.



Edited: Fri June 18, 2010 at 12:25 AM by rastoma

bohica2xo on Fri June 18, 2010 2:24 AM User is offline

It did not need converting. It still had R12 under pressure.

A recovery, a new drier & orifice tube. Recharge with R12, and down the road it goes.

Now, even to return it to R12 would mean breaking it down to flush everything. Lots more work.

The death kit adds oil, so you have too much in the system. The dryer was not compatible with 134a, so it may have eventually failed - spreading gunk everywhere in the system. The pressures are higher with 134a, and even higher with too much oil. This means added strain on the compressor. we call them death kits for several reasons. Sadly the package makes them see like a complete solution.

B.


-------------------------
"Among the many misdeeds of the British rule in India, history will look upon the act of depriving a whole nation of arms, as the blackest."
~ Mahatma Gandhi, Gandhi, An Autobiography, M. K. Gandhi, page 446.

NickD on Fri June 18, 2010 9:54 AM User is offline

Not being sarcastic with my remarks, experience is the key reason, my first option would be to trade this thing up to a 1996 where great improvements were made in not only the AC system, but in the ride as well.

Reasons? Even sticking with R-12, the low side would kick up to 65psi on a 100 degree day, passengers would fight to sit in the front seat and try to crawl into the vent hole to stay cool. Reducing the charge did help a little, but then would cycle like crazy at lower temperatures, a no-win situation. Here, R-134a may help with a parallel flow condenser, try to emulate the 96 version. But the evaporator is too small to really help much. R-4 always gave problems with that huge O'ring and a tin case, with rust build up on that tin, it leaks like crazy. Augmented by that single lip compressor seal. Blend door weather stripping rots, but very easy to repair, after you remove the dash.

One solution was to borrow your old mans' car on those hot days, son still says his best day is when he got rid of that thing, that, and a myriad of other problems, constant problems. Offered to give it to me for free, said thanks, but no thanks, already have enough problems. And I am not being sarcastic on this.

rastoma on Tue June 22, 2010 5:50 AM User is offline

Quote
Originally posted by: bohica2xo

The death kit adds oil, so you have too much in the system. The dryer was not compatible with 134a, so it may have eventually failed - spreading gunk everywhere in the system. The pressures are higher with 134a, and even higher with too much oil. This means added strain on the compressor. we call them death kits for several reasons. Sadly the package makes them see like a complete solution.
B.

I can appreciate that. As I tried to state in my original post, this is a part time use vehicle to deliver mail in. Driven 1-2 days a week so I don't need fantastic air, just some air would be nice as there are a few roads that have no boxes that I could raise the windows and cool off for a few mins.

I couldn't afford to take it to a shop for leak testing and recharge at $200. Plus even if the cost would be close or more, I have gotten into this a/c DIY and really want to learn to how to do it myself for the fun of it. So future repairs and on other cars will be a lot cheaper now that I know what I'm doing with the help of everyone here. Plus I can spend the money in 'pieces' as I accumulate the parts I need instead of dumping a lot of cash on some refrigerant only.

I only put the r-134a in last week and the compressor hasn't ran more than 10 minutes total since then. I will not operate it again until I flush it, replace accumulator, OT and rings.

bohica2xo on Wed June 23, 2010 10:43 AM User is offline

If the vehicle is only to be used for low speed operation like mail delivery, I would consider locking the fan clutch up. This will improve the condensor airflow.

I got "into MVAC" for the same reasons a few decades ago. I was broke, in high school, and wanted my A/C to work again. There was no internet, so I took the RSES courses at the local college.

Learning the basics on a vehicle that is secondary will let you do the work at a learning pace - if it is apart at 10 pm you can still go to bed knowing you can get to work in the morning.

Good luck with your project.

B.

-------------------------
"Among the many misdeeds of the British rule in India, history will look upon the act of depriving a whole nation of arms, as the blackest."
~ Mahatma Gandhi, Gandhi, An Autobiography, M. K. Gandhi, page 446.

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