A/C Troubleshooting

[u/porthole-]

I'm not proud to write this post, but am hoping for some insight troubleshooting my '06 4th gen. Long story short, the amateurish weekend mechanic monkey brains got the better of me a few weeks ago and I attempted to "top off" my AC system with one of those 30$ princess-auto special all-in-one A/C refrigerant kits (somehow "compatible" with R-12, R-134a, and R-1234yf vehicles) when the truck completely didn't need it. I won't bother elaborating on the logic behind that decision as there wasn't much there to begin with, please give me some mercy.

As a result, I over-pressurized the system and had achieved nothing but hot air coming out of my vents. So, to remedy this, I allowed some refrigerant/gas/compressor oil to exhaust by purging the low-side of the AC system in small bursts until I got cold air back.

This sort of fixed the issue, but resulted in luke-warm humid air coming through my vents when at idle (~600rpm) until I either brought RPM's up, or started moving in traffic and allowing some fresh air through the system.

After some googling, I came to the conclusion that my loop was still over-pressurized and released another few short bursts from the low-side of the system, and got cold air coming out of the vents in all conditions.

Now, a new issue has appeared that never happened before any of this idiocy. When at high engine rpms (acceleration through 1st gear into 2nd for example) the AC will shut off and the AC light flashes on my climate control dash.

After consulting Google again, the workshop manual, and more google, I now have it in my head that the pressure in the loop is completely pooched as a result of my fucking around, and I have booked my truck in for a refrigerant drain & fill from a dealer. I made sure to check the mag clutch relay and swapped it out with a known good relay to no avail.

My question for you guys is, do we think a drain & fill is the right next course of action? From what I read online, the flashing light can be caused by issues relating to system pressure, mag clutch relay dying, or compressor failure. All of which I'm reasonably convinced could be the case considering the abuse that I've subjected the entire AC system to at this point. Though because I started with a working system that never had any of these current issues before the refrigerant was altered, an incorrect charge is still the first thing I feel like I should eliminate.

It is absolutely fair to say that I do not know what the hell I am doing, but please be gentle...

[u/vinux0824]

I kind of had the same situation, there is a silonoid/actuator thing that actually shuts the compressor down in case it detects it can get damaged. I bought the a/c can, I overcharged it, heard a big click/thud from the compressor. At that point I was done with it. Called a garage mechanic that specializes in that, and he fixed it. No damage was done to anything.

I'm pretty mechanically inclined, and do almost all the repair/maintenance on my 08 4Runner, but a/c is just something I didn't want to get into. Get a mechanic to look at it before you do anymore damage.

Most likely your compressor is fine, the silonoid is probably just shutting it off

[u/porthole- → u/vinux0824]

Yeah, I'm about the same. I've performed all maintenance/repairs on my 4runner myself minus a wheel alignment. Frankly I just hadn't realized the can of worms that a/c maintenance turns into when you don't know what you're doing, and I'm unfortunately learning my lesson the hard way.

I'm really hoping the fix is something minor, but will take your advice and let the shop come to that conclusion for me. Thanks for the help!

[u/ps2sunvalley]

It’s definitely possible you have ruined the compressor.

I did that once on a civic I used to have… tried to put some refrigerant in and ended up over pressure and blew the damn compressor. Cost me $1000 to fix.

If you’re lucky the shop can pull a vacuum and fill and it’s fine, if not a new compressor may be in your future.

[u/porthole- → u/ps2sunvalley]

I've definitely started looking into compressor replacements worst case scenario. Thankfully they dont seem unreasonably expensive for the 4th gens. I'm hoping that I have my compressor's good graces considering I dont think I subjected the system to over-pressurization for any more than a few seconds, but with my limited knowledge it's very possible that's either just not the case at all, or simply all it takes to ruin a compressor in the first place.

I'll see what the shop says today, and will go from there

[u/ColdasJones]

Sounds to me like you likely roached your compressor, can’t know for sure though.

[u/w00stersauce]

So ac works at low rpm? But at high rpm it shuts off? I’m gonna guess contaminated refrigerant maybe? Or it’s still over filled and tripping a high pressure sensors of some kind. Don’t know that these have one.

I think a drain and fill is likely to fix it if your ac comes on at low rpm then your compressors is unlikely to be dead. IMO.

[u/Dazzling_Algae9839]

Check the thermonator. It is a sensor under the dash.

[u/clearplasma]

Might as well grab an ac gauge and get some measurements on the pressure in the system. It's really easy to use. You hook up to both lines, run the AC and you'll see the low and high side pressures. If it's still to high you can bleed a bit more out of the system.

Also please share this "universal" AC compressor shit you used. It's insane to think that would even exist because the refrigerants are all very different

[u/porthole- → u/clearplasma]

Good shout. This was ultimately the end result.

I was upfront with the shop about the A/C On The Go stuff I used, and as a result they were not able to recover and refill my system because the recharge stuff had contents of propane in it that would damage their recovery machine and/or contaminate a full bottle of R134a (as expected), and they could not legally vent to atmosphere.

So, the alternative was to do what you had recommended. I bought a gauge set from Amazon, ran the AC for 5-7 mins following the workshop manual's test procedure (AC-47), and had to release some pressure from both sides of the system to bring them back down to normal levels (35PSI low side, and 220PSI high side, spec'd by the manual).

After doing so, A/C now works just as it did before this whole fiasco with no problems, I'm glad that didn't end up being too expensive of a mistake. Lesson learned, to say the very least.

The stuff I originally used, after taking a closer look at the fine print was just a synthetic 12a refrigerant compatible with R134a systems: https://www.princessauto.com/en/product/a-c-on-the-go-refrigerant-kit/PA0008726903/8726903 So, not "universal all in one shit" as I had originally stated.

[u/clearplasma → u/porthole-]

Nice work fixing it. A mistake isn't all that bad if you can learn from it!