where to buy cheapest AC flush gun and flush
 

I saw one on Northern tools site for $49. anyone know if someplace rents them and sells flush? or is there another online source? can you make a flush gun from something else? I was thinking something like a clean new sandblast nozzle and a jar?

You don't need a flush gun; it's not worth the money for DIY use. Just pour the flushing fluid into the component and blow it out with compressed air.

A typical parts store should sell the fluid.

Fill the part with flushing fluid, shake it around, and blow it out with compressed air. Save the fluid and flush with it again, adding new fluid as necessary, and discard the used stuff when it gets too nasty.

That will work better than the $49 Northern Tool special. Be sure to purge all of the flushing agent with lots of dry air.

free loaner
 

AutoZo** place loans one free. Just leave a deposit.

Sure, but it's not worth using.

is it normal to remove coils? seems like a gun would be needed to get the evap and condensor coils without removing them

You can flush the evaporator in place by connecting hoses to it. The cheap flush gun really isn't worth using, because you can still do a better job by pouring fluid into one of the hoses and following it with compressed air.

I would definitely remove the condenser to flush it. Unless it is a parallel-flow condenser, and then I would highly recommend just buying a new one.

I just used some hose and a (very clean) dish soap bottle filled with flush solvent to flush out my A/C system. You can put solvent in the hose and blow it into heat exchangers with compressed air that way. No need for a flush gun, or nylog, just coat O-rings in mineral oil... that is what the local A/C shop in business for 50 years told me.

I suppose you could remove the condenser and powerwash it/ paint it with evaporator conductive paint. If you strip out the top brass nuts on the expansion valve, you can clean the evaporator coils when you remove the evaporator box for a new one :D

Pretty sure CarQuest or NAPA has good flush solvents in quarts, not in a spray can. 2 quarts were enough to flush everything out well for me, got those for $9/quart from my local A/C shop.

To avoid having to access the evaporator from inside the car, drill out the bore of the old expansion valve, then reinstall it. Then you can flush the evaporator from under the hood and avoid having the flush mess up your car's interior.

now that sounds like a great idea. can you do a quick text step by step to drill out the expansion valve?

By the time you remove the expansion valve, drill it out , put it back in, flush the system, remove the expansion valve again, replace it with a good one. you can just remove the valve and flush with hoses.
Attach a hose to the in and out with pipe clamps, pour mineral spirits in (No need for "flush fluid") and blow it through with compressed air.
No need to remove the condenser either, if it's the original one. Disconnect compressor and put a bag over it to protect it. Remove the receiver/dryer and flush with your hoses again from under the hood.

Don't make this harder than it is.

Danny

Engine Cleaning Gun
 

I own one of these http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=97014 and fine it useful for a lot of things. Seems like it would do a fine job of blowing solvent through the A/C system.

I used a borrowed flush gun...thanks again Jummy! And it worked really well for me. I used methanol as the flush agent, thanks to advice from an old school A/C guy. Mthanol was $5 per gallon, I bought two, but ended up using 3/4 of a gallon. My system was "converted" to R134a, the fist compressor blew a front seal. Rebuilt compressor and drier added and charged w/R134a. Leak noted a few weeks later, and dye was added. Leak found with catastophic high pressure line failure. It was spliced! High pressure line was rebuilt by local hydraulic hose builder for $20. Remanned compressor had a failed clutch, just after the warranty expired. So that lead to a new compressor, not remanned, new drier again, new expansion valve, new temp switch, new high/low pressure cut off switch--since Freeze 12 is a blend of 134a and something else, new expansion valve, and new o-rings.


It as been almost 3 summer seasons now, and the A/C is still working well with Freeze-12.

Take the expansion valve out - take a drill and correct size bit and drill through the small side - you'll figure it out when you get the e-valve off. Its fairly soft metal - be carefull of the threads on the valve - reinstall drilled out e-valve. tighten down all four connectors - just hand tight will work. stuff a rag around valve to be safe. Flush and flush and flush - It works really well.

Now I know that sounds simple - the reality is it took me 30 minutes to get the nuts lined up with the valve and not cross thread it. Plus you get the pleasure of doing it twice - to put the new e-valve on.. on the 126 its a real PITA... Also hang the compressor hose ends INSIDE a bucket - other wise you'll spew the flush and oil everywhere..

so 2 flush alternatives on this thread
mineral spirits
methanol

can I get a vote which is better? or should I stick to commercial AC flush?

I will most likely be putting in Freeze-12 as I have already purchased 6 cans and the kit to change it over. I was going to use R12 but I dont have the kit to fill it from the can and I cant seem to find any local

I have a side piercing dispenser that fits the cans...oil charge, R12/Freeze-12, 134a, through the guages. I left the 134A quick connects on the car, but have the Freeze 12 sticker. Since my car does not have the Barrier hoses, I do have to add Freeze-12 yearly. About 1/2 a can. The other half goes in the Nissan Truck. It has been on Freeze-12 for the past 7 years.

so one of the arguements I have heard about freeze-12 is that it leaks portions of the mix faster and screws up the ratio, eventually a loss of performance from haveing an incorrect mix. are you seeing this issue with a 1/2 can per year leak? I was thinking if it leaks it needs fixed, and if not then there is no mix issue, so why not use the freeze-12?

can you shoot a picture of your side peircer attached to the guages? dont you loose al lot of the refrig in the hoses? I was thinking the long hoses on my guage set would be a big waste

I'll have to take the pic at home, since I am at work now. I'm sure there is freon loss due to the longer hoses, but if your presures are correct, it's not a big deal in the grand scheme of things.

I have not noticed a degradation of cooling capacity, and I do not know what leaks and what stays. When the outlaw 134a, I'm sure there will be something else for us all to squabble over, freon wise...

I bought the flush gun kit for $30 on EBay - do a search and you should see them.

At the same time I also bought a quart of FJC flush solution on EBay. After getting into the job, it was obvious that more than a quart would be required. In searching around some I found the best price for what I wanted (gallon size) was on Amazon. I used the quart just to clean out the compressor manifold lines (short line to condensor and half-line towards evaporator valve). Don't forget that there is an O-ring near the brake booster (on the 300SD) where the manifold line joins with another short line into the evaporator - if you are replacing O-rings this is a good one to get.

A gallon is probably good to flush a system that does not have debris inside (from a failed compressor) and is marginal if you are changing refrigerants (and thus the oil type).

Paying $30 for a convenient way to inject flush solution is worth it to me. The pressurized gun allows me to flush solution UPHILL and thus fully saturate the hose being flushed. When you flush downhill you might not fully flush the upper 1/2 to 1/3 of the flat sections of hose.

Ken300D

so right now I am leaning toward this solution.

harbour freight gun $5
http://www.harborfreight.com/cpi/gifs/clear.gif
http://www.harborfreight.com/cpi/gifs/clear.gif

mineral spirit flush (however many gallons it takes to get it all clean

final flush with a quart of Dura II from NAPA

I also have Ester oil to flush the compressor

Three key points:

- Anyone who is "overhauling" their system and leaving their old expansion valve in service is making a mistake.

- The few minutes it takes to drill out the old expansion valve and reinstall it is well worth the effort. Unless you like flushing fluid all over your carpet and upholstry.

- The best way to do a job isn't always the easiest way.

So...you want to waste money on a flush gun and cheap out on the flush fluid.

I removed the carpet panels and hooked up some drain hose to the evap fittings. This was before I knew of the drill out the exp valve trick. I like that idea. Thanks Tango!

well, I got a $5.99 flush gun and the only flush fluid that I can find for this weekend is NAPA $34/qt :eek:. so yes I am going to cheap out on the flush fluid. I bought one qt to use as a final flush but I dont want to spend $200 on flush

one more question.

what direction is correct for each line?

DOWN is the perfered direction when speaking of certain fixtures in the bathroom.:D I'd say it doesn't matter which direction you flush as long as you flush all the way "thru" and get all the material out.

On the metal lines it really does not matter, but the rubber might be different story. Low side is suction side, high side is discharge side, Small lines flow to the evaporator from the compressor and condensor.

Like this...Compressor to Condensor, then to drier, then to exp valve, through evap, back to exp valve, then to compressor.

It probably does not matter the flow of flush, unless there are metal shards in the rubber lines.

I can do two cars with one of these:
https://www.ackits.com/pc/200011/Flush/200011+-+Hecat+Safe+Flush+%28.5+Gallon%29

answer
 

http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=97014

Engine Cleaning Gun


The fast easy way to clean dirt, grease, grime, salt, mud, and more! Can be used with a variety of solvents. An essential tool for farmers, truckers, contractors, shops, and garages. Includes 4 foot solvent suction hose with built-in solution strainer.


Lightweight and easy to handle
Recommended air pressure: 60 PSI
Air consumption: 3 CFM @ 60 PSI

Air inlet: 1/4''-18 NPT; Overall dimensions: 3" L x 1-1/16" W x 15" H



ITEM 97014-2VGA

$5.99
http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=97014


http://www.harborfreight.com/cpi/pho...7099/97014.gif


Have a great day

I think that it is a STUPID law, and I am not trying to be critical in any way. What refrigerant you use and how you use it SHOULD be totally up to you, although I am not in agreement with your choices.

I am only posting here to point out that you are publicly posting information about your breaking of Federal Law.

You are required by law to have the CORRECT fittings and sticker for the refrigerant in the vehicle.

Again, this should be your business and as far as I'm concerned it is, but I just didn't want to ignore this in the event that you were not aware. I wouldn't want any of my MShop brothers to get into trouble.

got one today, they tried to charge me 7.99, I showed them the ad I printed from the online store. whenever I go there I bring prints of the price online, it is always cheaper online. they get my money anyway, I got a nice set of aluminum AC fitting wrenches.

I would tend to agree with this - the best way to flush any solid debris out of the A/C lines is by a downhill flush.

However, consider the problem of flushing a pipe. Let's say this pipe contains oil and some small amount of fine particle debris. The pipe is 1" inside diameter and is 20 feet long. The pipe is essentially flat with one end a foot higher than the other so that liquid put into the high end flows downhill and out the other end. While in use, this pipe has been under pressure and has carried the oil solution (with a little "dirt" debris in it) forced through the pipe by a pump (compressor).

Now you have the pipe open at both ends and want to flush out the old oil and get as much debris as you can out. Do you simply hand pour the flush solution in to one end and let it flow out the other end? If you do that, you will clean only the lower half of the pipe, because you are not forcing through the solution under sufficient pressure to fill the pipe and clean the top of the inside.

If you go to the bottom of the pipe with a flush gun and introduce the flush under a small amount of pressure until it completely fills the pipe and flows out the higher end - now you have saturated all the inside surfaces of the pipe with the flush solution. Now you are really diluting and flushing out the old oil.

But you may not be getting all the solid debris to flow out the higher end. So, when you have clear flush solution flowing out with the "uphill" method, release the flush gun and let the solution come back out the lower end. Go to the upper end and flush downhill. The particle debris should be mostly in the lower half of the pipe cross-section by now since it was loosened by the uphill flush solution saturation. A healthy downhill flow should now clear it from the pipe.

Some of the lines on the car A/C systems are essentially like this hypothetical flat pipe. You won't completely flush them out of old oil and debris if you only flush downhill.

Ken300D

so heres what I ended up doing. flush gun was not needed as a couple guys said. glad I only spent $6 on the HF gun.

1. removed the expansion valve, drilled it out and replaced it as was suggested here

2. disconnected the dryer line and the low side line, ran the dryer line out the side under the hood hinge with a piece of hose to a bucket

3. poured about a quart of mineral spirits into the low side line and then blew it out with dry air, repeat until flush comes out clean

4. poured in some dura II flush and blew that through, then I hooked a dry air line to the hose and let it blow through for about 15 minutes

5. removed the drilled out expansion valve and blew out the evap for another 5 minutes or so, I read to hold a finger on the exit and "pop" the air when you let go, this seemed to really blow it out nice.

6. replaced the orings with new green ones and put on the new expansion valve.

7. removed the rest of the low side line and the high side line

8. marked the orientation of the hoses and took them all apart

9. reattached the high side line portion to the condensor and pointed to a bucket

10. attached a hose to the condensor exit line and put in a funnel

11. poured mineral spirits same as before and blew through with dry air

12. reflushed with dura II

13. flushed the remaining lines seperate

14. replaced all orings with oiled green ones

used 2 gallons of mineral spirits at $12/gallon and one quart of Dura II at $35 quart. The mineral spirits are going into my parts washer so it will get some more use

I just flushed the A/C system on my truck this weekend... The AutoZone flush took forever to come out clear. At $20 a quart I decided to try something else. I ended up using lacquer thinner (a/c is much easier to work on then a benz... figured it was worth experimenting). It worked MUCH better than the flushing fluid and evaporated faster as well. My compressor was dying of black death, and I used a LOT of fluid to get everything coming out clean. Hopefully I got it all!!

As far as flushing direction, if you have removed the component (i.e., condenser) I would lay it flat and flush from both directions. Same principle as flushing your radiator in the opposite direction of flow. Always seem to get more out that way. :cool:

Why on earth is a flush gun worthless? My flush gun can add a quart of fluid at a time under pressure. It's also a whole lot easier to fill it up versus getting a funnel, filling the part up, etc. To each his own I guess.

edit: I have a refillable compressed air powered flush gun... Those aerosol ones at AutoZone are probably worthless. If nothing else, there isn't enough fluid in them.

it was just as easy to pour it in the tube as the gun, difference is i didnt want to spend 49 for the gun and wait a week for it, i had this weekend open. napa wanted 70 for the same gun. so far i am very happy, its 95 here today and with all the vents blocked except the driver dash vents it blows cold air in my face enough to be comfortable. now I would like to figure out how to pipe the cold air through my seat back

I used a garden sprayer which I already own. this will push a lot of fluid thru rather quickly.

then lots of compressed air.

no smoking allowed,do at your own risk, etc........

http://tbn0.google.com/images?q=tbn:...es/hudson2.jpg

I have always used Isopropyl Alcohol when flushing A/C sytems. Some of the A/C flush products are expensive and are difficult to remove from the system completely. Alcohol is cheap , cleans well, and any residual amount left in the system will evaporate when you pull a vacuum on the system.

I used one of these:

http://hecat-inc.com/flush_gun.htm

It sends pulses of fluid, separated by compressed air. It's a violent action, which got the system clean with just a few passes of fluid.

If you buy flush fluid by the gallon, it costs about $40-45. You use it instead of lacquer thinner because it won't harm your paint or the rubber parts in your system, and it is non-toxic.

Violating the TxValve to use as a hooking up point is the method prescribed in the MB Factory Shop AC manual.
That manual also says which direction to flush the lines.
The metal manifold which attaches to the compressor is supposed to be renewed because they think it can not be cleaned properly.
I really would not take a chance on guessing as to which fluid will clean properly and NOT deteriorate the insides of the AC lines... seems like an unnecessary chance to take.

thats weird, of all the lines I would have thought the metal manifold is the one that would clean the best..... Anyway, the manual is geared toward fixing in any situation. Maybe a million miler would need all new parts, but mine was working fine last year and only stopped because the PO's mechanic didnt mount the compressor right, breaking the bolts and eventuall it broke the seal and leaked freon. It was a pretty clean system, but even with that the flush cleaned out a lot of black oil. From what Ive read whatever I did wrong will show up in longevity losses so I am keeping my fingers crossed, it is really hot here.

Actually I assumed it was directed towards any ' black death ' type situation and that although they did not mention the word ' screen' or ' filter' that that metal manifold may have one which is not able to be cleaned if contaminated with certain size or types of material.

Oh I never thought of a screen in there. anyone know for sure? I flushed those hoses in both directions since they were seperate.