I am going to flush my air conditioning system in my 84 300SD. The R-4 compressor is running just fine, but there is too oil much in the system. The car had R-12 (mineral oil), then was converted to R-134a (do not know what kind of oil). There was way too much oil in the system because the oil bubbled out of the service port when I removed the gauge. So I flushed the system and put mineral oil and Duracool in it. I think I put too much oil in the compressor.

I used a flush agent with my blow gun to flush the system, but I thought the agent was too thick. It was possible some was left in the system.

I was told you could use paint thinner or mineral spirits, but it would leave a residue.

I think dechrolinated brake parts cleaner is good because it cleans well and dries fast.

So, which is the best solution to flush an air conditioning system?

I use stuff called AC Blowout that I purchase from my local automotive a/c supply house.

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Jim

The folks at ACKITS told me to use Mineral spirits with their flush gun kit..

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89 300SEL Money Pit

92 Blown Buick Ultra Pimpmobile 220K and adding 1K per week

88 Wagoneer Slightly modified (Not for soccer moms)

04 Kia Sedona with every option... NICE

Although I voted for A/C Flush Agent, you did not give me the choice that would be accurate for me.

For a system that will require LOTS of flushing, I use mineral spirits and alot of it, with a final flush of regular a/c flush. The reason is that mineral spirits is cheap but leaves a residue. The final flushing using a/c flush gets out the residue.

Good luck,

I also voted (mineral spirits), but my choice doesn't reflect the system I use. Like LarryBible I use mineral spirits for the bulk of the flush action, then follow with brake cleaner or lacquer thinner to remove mineral spirit residue. Whenever I degrease auto parts where I work, I use the same logistics (mineral spirits followed by alcohol) because my parts need to be absolutely clean. Mineral spirits for economical flushing -- brake cleaner for quality flushing.

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95 E320 Cabriolet, 159K

Lacquer thinner. Cheapest stuff I can buy. Use a lot of it and flush out ALL the crude. Amazing how much is in there. I've seen it run near black the first couple of slugs of thinner. For real fun, Try flushing an old Chevy suburban with rear air. Must be a mile of hose. (actually there are two hose over 20 feet long!). Doesn't take much to foul up A/C so make sure it is really clean then pull a vacumm on it overnight.

Well.. My plan is to use paint thinner, followed by denatured alcohol.. I will be working in an enclosed area, and I'm afraid the the laquer thinner would bramage my dain..

Anyone see a ploblem with a follow up of denatured alcohol???

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89 300SEL Money Pit

92 Blown Buick Ultra Pimpmobile 220K and adding 1K per week

88 Wagoneer Slightly modified (Not for soccer moms)

04 Kia Sedona with every option... NICE

Alcohol will get you the "clean" that you need - I can vouch for that. Virtually no residue.

Damage your brain??... Yes, it's better to get drunk than poisoned. Keep in mind the denatured stuff can vary in chemistry. The stuff I use in the lab is 94% ethanol, 5% isopropanol, 1% water. Sometimes alcohol is denatured with up to 5% methanol.

Don't forget the flammability hazard. You'll be vaporizing a lot of volatile liquid. Don't shatter the light bulb in your droplight while doing this!... and no smoking!!

I suppose these two issues provide a good argument for using the a/c flush LarryBible uses.

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95 E320 Cabriolet, 159K

I better disconnect the battery

Laquer thinner is some pretty volitile stuff too.. Hmmm. Maybe opening the doors, and windows , and using a fan would be a good idea.. especially while doing the evaporator..

Couple of fire extinguishers nearby might be a good idea too..

jay,

You are a wise man. Lacquer Thinner would do a great job, but you have to consider the effects on yourself.

Have a good flush,