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AC Compressor R&R how to?

Thank you guys for helping me, Diag my 2004 CRV with AC issues below. The consensus is that the old compressor was not working (I am guessing just plumb wore out after 230,000 miles in SC heat). So the Compressor and Dryer are ordered… Just under $300 shipped to my door, I’m good with that…

I have never done this job before, but I know the theory… Evac will be done where I work, so no fear there (plus I don’t think there is much in there)…

Tell me if I am missing anything, or if there is another way.

  1. remove feed drive belt
  2. remove lines from rear of compressor
  3. Unbolt compressor
  4. follow AC lines and detach from other side, so I can flush the lines with solvent
  5. Blow flush solvent through evaporator core, then let air out for a good 20-30 min or more
  6. Replace dryer (this car uses a drop in dryer, can I clean its compartment with something?)
  7. I have been told I can’t flush the condenser (is this true)
  8. Oil new compressor with liquid R134 Oil (about 3-4oz)
  9. Reassemble with new o-rings
  10. Vac out system (let me ask about this, I have an air powered vac pump that I have used for years. My compressor is a typical stand up 30 Gal, and it will air down and click on fairly fast with this pump… Can I just let it run for 20 min with the vac attached to really get a good vac on the system?)
  11. Recharge to proper PSI levels.

Did I miss anything?? Anything you would do that I did not talk about?? Any advice on any of the steps??

Thanks again in advance

You’re also going to have to replace the expansion valve at the evaporator. Once removed then the evaporator can be flushed. You can try flushing the condenser. But the most effective way is to remove it from the vehicle so it can be filled with the flushing solvent and allowed to soak. Then position the condenser where gravity and compressed air forces out any debis. If it has a drop in drier just clean the canister with the solvent or brake cleaner.

I don’t like the compressor operated vacuum pumps. They don’t remove moisture from the AC system. And when an AC system is completely rebuilt, it’s recommended that a REAL vacuum pump pull a vacuum for at least an hour to remove all the moisture. You can let your compressor run for an hour with the vacuum pump you have, and it still won’t remove the moisture.


I thought that was the whole point of a vacuum, to boil and remove the moisture.

That is the point. But that’s with a REAL vacuum pump. A real vacuum pump will constantly pull one atmosphere or 29.92 " Hg. At this pressure water boils and is converted into a gas so it can be removed from the system. Your vacuum pump relies on the compressor pressure and volume to pull a vacuum. As the compressor pressure and volume fall off in the compressor tank as the air is consumed, the vacuum at your pump also falls off. So you’ll remove the air from the system, but not the moisture.


I replaced the condenser and dryer to the Tacoma a couple of weeks back and used this vacuum pump sold by Harbor Freight. l left it on for a good 40 minutes and, never having done this, it was a bit unusual to see a bunch of steam come out. That eventually stops and that’s when all the moisture is removed. Works like a chimp.

There are 20% coupons out in various magazines so you can get it for just over 80 bucks on top of the sale.

They also have a manifold set that works very well.

Where do you live? If you live in a temperate climate, with summer temps in the 80 degree range, your a/c should work ok using your vacuum pump. But like @Tester said, those pumps do not, can not, will not ever remove all the moisture and noncondensables from your system. There’s a reason no professional shop that warranties work uses that kind of pump. I’d have to agree with @RemcoW that they “Works like a chimp.” I assume that was a typo :slight_smile:

Also, when you say you’re going to flush the components with solvent, I assume you mean a specific A/C flush chemical and have the pressurized equipment to adminster said chemical?

@asemaster; Little known fact, perhaps, but if you can stop Chimps from throwing stuff at you, they are actually very industrious workers.

It is pretty much the same with some HF tools: that HF vacuum pump and manifold actually works very well. It probably won’t survive pro use but I was able to repair my AC and have tools left over. The manifold was already used used to recharge a friend’s car.

I guess I could always make something like this as well… LOL, I wish I was this smart and had this kind of stuff lying around the house… I think the Mrs, would become a Miss if I did though… :slight_smile:

LOL! I like it!

BTW this is what I was going to use now, and I live in SC where 100+ and humid is not uncommon, so the AC needs to rock…

HF sells something very much like that so thought about that when getting ready to fix my AC.
They say that even the HF unit works on the forum but do think your compressor will get a real workout with that tool.

I decided against it because of my experiences using a venturi action brake evacuation pump that I got my hands on. It kinda worked but it was a lot of noise for what it did. There’s a not of hissing and whistling action to the point where all the neighbors’ dogs were quite up in arms - and that was just to draw out one line.
Ended up using an old camping mattress pump instead for that purpose.

Yes, I is a redneck.