A/C compressor New v/s Used

[071990Q45]

Hello

I have searched the threads and found little information on A/C compressors for the Q. I have a 91 Q45 and am in need of a compressor. The new ones range anywhere from 250-500 dollars. Used ones are 70-100 dollars. What should I be concerned with when buying a used one? Is the process of replacing one involved or is it simply bolt on?

I'm not a complete novice - I've replaced the master cylinder, power antenna, clock, all three belts, and done an oil change on the Q. Is this something I should try, or do you need special tools?

I'll probably end up going with a new or possibly rebuilt one...

Thanks,

Sam

[qsiguy]

well, my compressor died a few weeks ago and I bought a used one from a NICO member here. You'd want to make sure it was sealed up when it was removed for one. Really it's a shot in the dark with used compressors. It could work for years or weeks and there is no way to know. I figured it was worth the risk as I got this one for $70 shipped.

You'll need some decent tools, It's also recommended that you replace the "fluid tank" or dryer as some call it. The FSM calls it the "fluid tank". You need to make sure you have the proper amount of oil in the system. If you can capture the oil that comes out when you drain the system of freon you will know how much to add back to the system. If it's been leaking you may need a little more. I've read that adding 1 oz. will usually be enough for a compressor and dryer swap.

Are you planning on refilling it yourself? If so you will need some specific tools for that. You need to vacuum the system to pull the air/moisture out of it before you refill it with freon. Vacuum pumps are available for $10-20 at Harbor Freight. It's good to have a manifold gauge set. You can get them at Harbor Freight Tools for about $60-70 and I've seen them at Autozone for about the same price. You are supposed to reclaim the freon with the proper equipment but I don't imaging many DIY'ers have that equipment. I think I'm just going to vent it through a rag or something so I can try and measure how much oil came out with the freon. I think if I let it out slowly I won't loose as much oil.

I haven't started my swap yet, still getting the parts together (waiting for payday).

[Q45tech]

When a compressor begins to fail it throw tiny pieces into the gas stream first into the condenser then into the dryer filter and finally into evaporator where they may clog the expansion valve or reduce its function!

The entire system should be disassembled and flushed with proper solvents.................if you care about as new cooling and some simbilence of life on the new compressor.

We don't do this because a remanned compressor and dryer will usually last 12 months and that is the warranty..........we propose this extra work but customers rarely want to spent another $200-$300 in labor.

We give no warranty on customer supplied components as many remans from national retail chains won't last 3 months unless a full disassembly clean is conducted.

The oem flex hoses are not designed to last forever and acidic oil/water/ R12 combo EATS them out from the inside............thus small black flecks of rubber everywhere clogging up the system.

Essentially if want want like new AC you replace every component and make it brand new.............going cheap and skipping something will bite you.

[qsiguy]

I'll be happy to get a year or more on a used system. I'm willing to take a chance on a DIY job as a shop wants $1500+ for the job. I can do it for $200-300 myself so I'm happy with a year. It'll be 8-10 years before I'd spend $1500 doing it myself for $200-300 a pop even if I had to do it every year. Even a completely new system will likely need service within 5-8 years, then you get hit with another $1500+. Heck, I really only need to get a good 4-6 months out of it to count as a year because I only need it for about 4-6 months, then it's not used anyway until it heats up again.

I do plan to flush out all the lines as well as I can. What is concidered the "proper solvent" to flush out the system?

[elwesso]

I think most AC shops will be able to flush the system.. I would like to have that done for PM...

[Skibane]

I'll be happy to get a year or more on a used system. I'm willing to take a chance on a DIY job as a shop wants $1500+ for the job. I can do it for $200-300 myself so I'm happy with a year. It'll be 8-10 years before I'd spend $1500 doing it myself for $200-300 a pop even if I had to do it every year.

Re-doing it yourself every year is fine if you're unemployed, or don't place any value on all the spare time you spend fixing it. Personally, I'd rather fix it once, and then enjoy it for the next decade.

Quote »Heck, I really only need to get a good 4-6 months out of it to count as a year because I only need it for about 4-6 months, then it's not used anyway until it heats up again.[/quote]In cold weather, the A/C compressor kicks on every time you use the defroster - which means that a repair that lasts for 4 months won't even get you through the winter.

[Jesda]

I've had good luck with used compressors from Whitey's Wrecking in Spokane WA. $100. They clean it out and seal it for installation.

[qsiguy]

I was egsagerating to make a point that I can't see paying a shop that much when I know I can do it myself for a fraction of the cost. I am not a novice at auto repair and will do a fine job. I think it'll last much longer than 4 months or even a year.

Now anyone know what's a good solvent to flush out the system with?

[Q45denver]

Most auto parts stores carry it. I thinks its basically just mineral spirits.

[PopPop]

I was egsagerating to make a point that I can't see paying a shop that much when I know I can do it myself for a fraction of the cost. I am not a novice at auto repair and will do a fine job. I think it'll last much longer than 4 months or even a year.

Now anyone know what's a good solvent to flush out the system with?

Here are some good Castrol Flush Products I have used on American cars!

A/C Flush



Premium A/C FlushPart # 6644, Gallon - 4 per casePart # 6645, Qt. - 12 per caseNon-flammable and non-ozone depleting replacement for R141b. Strong cleaning action. Evaporates quickly. Safe for flush machines.

A/C FlushPart # 6544, Gallon - 4 per casePart # 6545, Qt. - 12 per caseA fast and effective way to remove debris and sludge from A/C systems. Use with a standard flush gun and shop air.

[elwesso]

how do you circulate it through the system? Compressed air?

I assume you would just undo the fittings at the compressor, flush, and then reattach... Woudl you somehow want to bypass the drier so you dont just flush things through there? just trying to think of the most effective way to do this, because its something Id like to do... If theres one thing I appreciate about a car its ICE COLD AC... I like it to "shiver me timbers"

[Q45tech]

YOU ALWAYS REPLACE THE DRYER EVERY TIME YOU OPEN SYSTEM...........no easy way to regenerate the dessicant.

[qsiguy]

I was figuring on using compressed air to flush. There are quite a few air blow guns that will mix solvents with the air. I have one already that I think I will modify with fittings for the a/c system.

Where do you find one of those "flushguns"?

[Q45denver]

You don't really need the flush gun if you get the flush in the aerosol can. However JC whitney has them.

[DrewQ45]

You don't really need the flush gun if you get the flush in the aerosol can. However JC whitney has them.

Okay I took a look at the JC Whitney site....

http://www.jcwhitney.com/autop....y=15

"AC - FLUSH & CLEAN For professional results when converting your older R-12 AC unit to R-134a."

Somebody please talk me out of doing a home conversion.....