5 Best AC Flush Solvent To Flush Your System (2023)

Hold up! Are you thinking about flushing your AC system with non-conventional solvents? You might want to think again if you don’t want to pay for the replacement parts all over again.

Yes, I know how frustrating things could easily get when buying components when you’re trying to flush the system. That’s why you need the best AC flush solvent.

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If you’re stuck on which one to pick, you’ve landed on the right page. We will go through some of the top choices after putting our hands through over thirty different solvents. And we’ve gathered the top 5 for your convenience. 

And if you’re doing this for the first time, sit back and relax. We’re going to dive deep at the bottom of the article. So let’s get on with the flushing without any further ado. 

1. FJC 2032 AC Flush Solvent

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There might be quite a few reasons why this flush solvent sits on top. As far as AC flush solvents go, you probably would expect this one to be promising. But it’s time to find out whether you should be spending your money on this or not.

For a plastic bottle that contains 32 ounces of solvent, this does show a lot of promise. But that’s not all it has. What sets this bottle apart from the competitors is the fact that the residue might be beneficial.

Don’t be weirded out. They do claim that the residue that stays after flushing is beneficial for your system. But it’s okay if you doubt this since you’re not supposed to leave it in.

Then again, FJC does say that their flushing solvent can work well with different oils. Some of the oils include ester, mineral, paraffin, and PAG, but we do need to test this out to verify. I mean, the solvent must clean the pipes well enough, right?

What would happen if you’re trying your best to flush out the debris and oil and you still end up with a dirty evaporator. FJC says that you can prevent the acid from forming with this solvent which could be deemed valid. But we have to test that out to see if it’s true.

Another thing that sets this one apart from the competitors is that it claims to be biodegradable. You can’t say for sure how true that is, but it’s a bold claim, to begin with. 

Since all the brands claim that their solvents are non-hazardous, that’s not a great point, to begin with. But if this solvent manages to stop corrosion, that would be an impressive feat. 

Another concern is the compatibility of refrigerants. This solvent claims to be compatible with R12 and R134A. These two are written right on the face of the container, so it should be fun to see whether the claims are valid or not. 

2. Four Seasons 69994 Super Flush Solvent

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Next up on our list is a neat-looking can of flush solvent from Four Seasons. But can it live up to the hype that it generates? Just like the top contender on the list, this one also comes with 32 ounces of solvent. But can it give you the same performance? That’s the real question.

Let’s talk about what we like about this product first. In terms of the pros, they claim that the solvent evaporates quite fast. It’s a pretty obvious claim. That’s because you shouldn’t even be using a solvent like this if it didn’t quickly evaporate.

If it lives up to the claim, it’ll be an impressive choice, but that’s a big if. Although it claims that the solvent can flush out absolutely any system, we wouldn’t be too sure about that.

So we put it to the test and found out that the solvent was compatible with R408, R404, R410, and R134. But it’s recommended that you use nitrogen for the drying-out process. This should make sure that no residue is left inside the pipes once you’re done flushing. 

But you’ve got to be careful because the solvent is highly flammable. Another problem that we’ve found about this solvent is that you might need more than one can. This is especially applicable if you’re trying to flush your truck.

Apart from this, the product does have some other interesting capabilities. You might not need it, but the solvent can be used as a sticker-removing liquid. Yes, we know this doesn’t quite make sense when you’re trying to flush an AC system.

But if you have some of the solvent remainings after flushing the system, you can always get more things to use it for. However, we would still ask you to get dedicated removers for other purposes.

3. Supercool AC Flush Solvent

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Coming in at third place is a “supercool” flush solvent from Supercool. Jokes aside, it’s actually up to us to decide whether this giant can of solvent is truly super cool or not. 

But we have to give points to Supercool for the huge can. This is the only product on the list that comes in a 1-gallon can. So if you’re working in the mechanical industry, you might be eyeing this one.

Supercool claims this solvent to be an excellent cleaner, but that’s to be expected from AC solvents. If they can’t cut through all the oil and debris inside the pipes and the evaporator, you shouldn’t spend money on them in the first place.

Another thing that you should consider while picking a suitable solvent is the evaporating speed. Every solvent needs to flush the AC system fast and evaporate. Leaving any sort of residue inside the AC system might cause harm to the refrigerants. 

While we’re on the topic of refrigerants, the company claims that this one is compatible with R22 and R410A. Most PAG oils stuck inside the evaporator and the pipes should be gone when you flush it with this, but you still have to give it time to evaporate.

Following the flushing basics is super important no matter how good a solvent might be. No one would want to replace their AC system again after a couple of months because they didn’t let the solvent evaporate. 

4. Four Seasons 69991 Dura II Flush Solvent

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Just like the first one on the list, this solvent claims that it’s compatible with R12 and R134a refrigerants. But where it loses out to the first one is the quantity. 

Although you might not see a ton of difference between 25 ounces and 32 ounces, it will show once you start to use the solvent. Those couple of ounces will make or break when you’re trying to flush a truck.

But what we’ve found out is that this one is good enough to take care of the smaller jobs. Once you’ve started to flush the condenser and the lines along with the evaporator, you might be pushing it.

It’s also a bit on the pricier side when you think about the quantity. This especially shows when you’re comparing it to the 128 ounces’ mammoth at second place. 

If you didn’t know already, you should never attempt to flush the compressor. That thing has to go. But using this solvent with the evaporator might yield decent results. 

You might have this urge to skip a solvent entirely and aim for a thinner. But we’re sure that a solvent dedicated to flushing a car’s AC system will show better results. These solvents work better with the rubber hoses as opposed to thinners.

5. Diversitech Pro-Flush Solvent

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The final one on the list is a solvent refill from Diversitech. And if we’re talking about value for money, this isn’t it, chief! Because you’re going to have to pay a lot for this little 16 oz. can of solvent.

When it comes to compatible refrigerants, this solvent claims that it only works with the R410a. You can give props to the brand for not making a fuss about it. At least it’s honest about the compatibility instead of saying it works with all systems.

Well, Diversitech claims that their Pro-Flush line maintains exceptional standards to ensure low toxicity. This is important since some people carelessly pour the waste liquid down the drains. But we might need a chemist to confirm that.

This little can is only suitable for one-time use for small car AC systems. The 16 ounces will run out before you know it. And you might need more solvent if you want to flush a bigger vehicle. 

So we’re not going to suggest this one to you if you’re about to flush a truck or an SUV’s AC system.

We’re not done bashing it because of the price just yet. You get so little solvent for so much money. This makes the product look like a pretty bad choice. So you can probably guess how it ended up here in the last place.

How To Use AC Flush Solvent

The steps are pretty simple. Since most people keep their evaporators as it’s pretty hard to replace, we will concentrate on the evaporators here:

Step 1: Pour Into The Kit

Firstly, you need to pour the solvent that you bought into the flush kit. Tighten the nozzles, and the kit should be ready to use. Every inch of the refrigerant path needs to be either new or wholly flushed before installing a new compressor. 

Step 2: Attaching To Evaporator

Next, you have to attach the flush bottle outlet to the evaporator outlet with an adapter. This will be the path through which your solvent will enter into the old evaporator.

Step 3: Connecting A Drain Hose

Now you have to connect a drain hose to the evaporator inlet. The drain hose will work to drain the debris and oils out of the evaporator along with the solvent liquid. It’s preferable to keep a catch can below the drain hose, so you don’t make a mess. 

Step 4: Time To Start The Flushing

The evaporator is flushed in the opposite direction to normal refrigerant flow. Set the pressure to 40 PSI till the solvent inside the kit is finished. 

Step 5: Cleaning Up

When the solvent is finished, it’s time to increase the pressure to 80 PSI. Keep the compressed air going for half an hour to remove all the debris from inside the evaporator. Repeat the process till you see the clear liquid coming out from the drain hose. Then you should be done! 

Safety Precautions And Measures

It’s super important that you keep safety in mind when you’re flushing your system. With so many chemicals involved in the whole process, you wouldn’t want to harm yourself, would you? 

You always need to be cautious when you’re working under the hood. And try to let the engine rest for a while before you start disassembling things. Here are a few safety tips that might come in handy.

• Try to wear loose clothing when working under the hood
• Be careful with refrigerants which may cause skin injuries
• The chemicals that you’ll be working with might be toxic, so don’t shove them down the drain
• Always wear a pair of safety glasses so that you can keep your eyes safe
• The solvents are highly flammable so keep them as far away from fire as you can

These should be the basics of flushing precautions. But these regular tips might go a long way if you have a knack for working carelessly. 

What Does An AC Flush Solvent Do?

So what exactly does a branded AC flush solvent do? If you’ve come this far without actually knowing what the solvents do, then props to you for your patience.

AC flush solvents help flush out your car’s air conditioning system. That’s pretty much the whole summary. Yes, it’s that simple.

So why would you need to flush the system, you might ask? Well, the most apparent reason is compressor failure. Once you’ve been using a vehicle for ten to fifteen years, they start to show their age.

And that’s when you get hit with compressor issues and other relevant issues. Compressors might also burn out at times. So when it comes to replacing the compressor, it’s a good practice to replace the entire system.

But that’s the most expensive route, and most people wouldn’t want to spend that much on an older car. That’s why they keep a couple of the parts, namely, the evaporator and the condenser, and then buy replacements for the other parts.

These flush solvents are chemicals that clear out the remaining PAG oils and built-up debris inside the evaporator and condenser of the vehicle. You have to clean them up thoroughly before installing your new compressor so that the new one doesn’t fail quicker than expected.

Refrigerant And Flush Solvent Compatibility

The gas or refrigerant that stays inside the pipes and the entire AC system needs to work with your solvent. You might not know this, but every refrigerant isn’t compatible with your solvent. 

Although shady brands claim that their solvents work with any refrigerants out there, it’s better to stick to the trustable ones for now. 

Not all solvents will be compatible with every refrigerant. Even the first one on our list is compatible with the R134A and the R12. So if R410A is running through your system, the solvent might not work without conversion.

And we know how costly the conversion process can become since all the prices start to add up. So it’s a good idea to complete your research beforehand. You can pick out the solvents which support the refrigerant inside your AC system for the best results. 

How Frequently Should You Flush Out a Car AC System?

Don’t get the wrong idea. Flushing your AC system is not a thing you’d want to do regularly. Modern cars have much-improved compressors, which can last quite long. Even the older compressors are still pretty decent by today’s standards.

But once a compressor fails, you might want to change the entire system and swap it with a new one. Most of you hate the idea of removing the dash and getting your hands dirty. So it’s perfectly understandable if you don’t want to switch out all the parts.

And it’s also a seasonable standpoint if you want to keep the evaporator and the condenser from the old system. This is why flushing the systems have become so popular among the masses. 

Not only can you avoid spending extra on a new evaporator or a new condenser, but you can also get your car’s AC system completely fixed.

I know it can be tempting. But you shouldn’t have to go around flushing out your AC system every chance you get. Once you get a new compressor, you won’t need to change it for years. 

But if you mess the flushing job up, you might be looking at a costly replacement in a few months. So even if we’re recommending flushing your system, it’s a better choice to replace the system completely. 

Should You Consider The Alternatives of Solvents?

There are a few alternatives that people might advise you to use for flushing the AC systems. While you change the entire system, excluding the evaporator, you can go for different solvents. But what if you want to take a much cheaper route?

Should you even consider using a cheaper route? I mean, what would you assume is the ideal flushing liquid? Some people might recommend alcohol or spirits. Though they do work to some extent, you should still opt for solvents that are proven.

An ideal solvent must not leave any residue in the condenser or the evaporator. Not even in the pipes! And you have you make sure that they are evaporating fast at normal temperature. 

If you keep these in mind, denatured alcohol is a decent choice. They’re proven to work great during the final flushing process. 

Another alternative that people seem to be quite fond of is mineral spirit. Although they might not give the effects of dedicated solvents, they might work.

Again, we’re not vouching for the use of these non-conventional ways to flush your system. Using a professional-grade solvent should still be the way to go. 

Frequently Asked Questions

Can You Flush Oil From A Car AC System With A Solvent?

Yes. AC solvents were explicitly made to flush out the oils and debris from a car AC system. You can opt for branded solvents for better reliance. But some of them do indeed work their magic to remove the PAG oils or paraffin. 

How Much Does It Cost To Flush A Car AC System?

Flushing an AC system can become extremely expensive at times. And if you’re not aware of all the hidden prices, you might be willingly burning a hole in your pocket. Along with the flush kit and solvent, you’re going to need all the replacement parts too. So all of these add up to increase the overall price of things quite a bit. 

What Is A Flush Solvent Made With?

AC flush solvents are usually made with a mixture of 60-70% heptane and 30-40% isopropyl alcohol. This is why using alcohol can be called an alternative to solvents. Sometimes they might contain fragrances too. 

How Much Flush Solvent Do I Need?

you have to make sure that you use the can or the bottle conservatively. It’s essential to have enough solvent to flush the evaporator, the condenser, and the lines. Usually, using less isn’t a problem. 

Final Words

That’s pretty much it from us when it comes to flushing your vehicle’s AC system. If you’ve gone through this article, you’ve probably already found your answers. 

Don’t shy away from telling us how your experience went. We hope you’ll be able to choose the best AC flush solvent for you after reading this.

Good luck with your purchase, and stay safe!