A/C R134A Manifold and can tap?

I couldn’t find anything definitive on the wiki or in talk regarding us having an R134A manifold gauge set for R134A and the proper tap for a 12oz R134A refrigerant can from my local auto store. Anyone know offhand? I’m pretty sure we have gauges, that hopefully are in working condition, but I’m less certain about the can tap.

We’ve got both. The tap is in the drawer with the blow guns I believe.

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I found the gauges hanging on the rack by the auto lift. It had an empty R134A 12 oz can screwed on it already, perhaps too tight. I needed a pair of pliers to loosen it. I glanced in the blow gun drawer for an older self taping adapter and didn’t see one. That may be a minor point now though with those being phased out in 2018 I think.

Unfortunately it turned out my pressures, 45 low, 350-400+ high, are I think due to an old, dirty and rather beat up condenser. It was nice to have a manifold handy to check though!

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Yeah, someone damaged a valve in the yellow line so it turns out you couldn’t have filled it if you needed to… (I believe it’s fixed now).

The older style is still being phased out, I think the last place I saw them was at home Depot a few weeks back. Most of the auto parts stores as well as Walmart are using the self sealing design. The same tap works for both.

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Not sure what type of automotive system you are working on, but unless you have the condenser caked in mud, road tar, or otherwise so obstructed that the engine is overheating, this seems high to be explained by just a dirty condenser, especially if you have tried washing it. If it is orfice tube, high pressure is more likely metal shavings from the compressor plugging up the strainer before the orfice tube. I suspect TXV systems may also may have a similar strainer.

I will note, that some newer vehicles, you can’t flush the condenser effectively, and if you have a plugged strainer, the condenser needs to be replaced.

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Good points, thanks! I should have said “next step” because the condenser looks pretty bad, other than the area protected by the license plate, and has not been cleaned yet. I figure I need to do so and recheck. If nothing else I’ll gain a little more experience in how much of an impact that might be having.

The car (Honda 2005 CRV 2.4L) can cool down when driving down the road, i.e. with lots of airflow over the entire condenser and higher RPM’s, but idling it’s blowing almost ambient air. The electric A/C condenser fan is working but only pulls over 30% of the condenser and that’s an area that’s really clogged and beat up.

Beyond cleaning the condenser I’d need to open the system and with the reclamation step by a shop needed that’s a time consuming DIY project for an in-service vehicle. Might be better for a shop to handle repairs or, given the age of the vehicle, maybe it’s time for a new car :wink:

I think it is a metering device or filter/dryer issue…did anyone use a leak stop in the system? Your compressor sounds like it’s doing it’s job…

@jphelps. Measure the subcooling…that will tell you if the condenser is doing it’s job.

In the past I would’ve made a beer bet, but now…I’ll just say my money is on a blocked filter/dryer or orifice.


I was going to mention non-condensables/air as another potential culprit.


Thanks guys. AFAIK, the system has never been serviced and it’s all OEM. We’re going to pop off the front clip in the morning, before it gets crazy hot, and do a coil clean and see if about straightening some fins, though the fin comb I have is perhaps not suitable for this type of fin design. I’ll post a pic.

The condenser isn’t as beat up as I thought. The radiator fan is on the left and the A/C fan is on the right, both behind the radiator.

No gauges at home to use but doing some basic temperature based testing here’s my results. It’s about 85-90 ambient this morning and with windows open, A/C set to MAX A/C and idling it’s blowing 70 degree air at the center vent. Revving up to 1,500 RPM it drops down to about 60 degree air. These are pretty dismal temperature differentials.

I’m leaning toward Thomas’s idea because I don’t think Tim’s suggestion would apply to an OEM scenario, never serviced situation. Note: I’m also assuming the DMS gauges are reasonably accurate. If they are in disrepair and reading high then I’d think perhaps low refrigerant.

It’s my GF’s daily driver so finding someone to evacuate the system so that I can dig deeper is not in the cards right now.

Anyway, I appreciate the suggestions and if there are any more I’m game.It’s a fun puzzle.

Both spinning madly when A/C is on?

The A/C fan runs when the compressor is running but I believe the radiator cooling fan only runs when the engine cooling system needs it.

I’m 90%ish sure both should be running when the ac is on…

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Find an owners forum and research this vehicles fan strategy. I would not expect any car to be able to keep the AC cold at idle, stopped, with only half the condenser having airflow, and it could certainly explain high pressures on the high side. Low charge would not explain high pressures on the high side. 350 high side is suggesting your average condenser temperature is around 170 degrees. (Presuming no noncondensables) That really suggests inadequate airflow to me. If you know both fans currently actually run for different reasons, you might have a bad relay, or other wiring issue. So I do suggest looking up how they normally operate for this vehicle.

Random Youtuber agrees, both fans should be on when A/C is turned on, even if engine coolant is cold…

I know. Low charge was speculation only and required that both the low and high gauges on the DMS manifold are reading higher than they should. I’ve learned to question DMS tools at times😉

I’ll double check on the radiator fan.

The other day on my car the low side was extremely low and the high side was extremely high. The orifice tube was clogged completely with material from the compressor eating itself.

Update: Radiator fan definitely not running when the condenser fan is. If it was running I’m sure performance would improve.

Open question: is that “working as designed” or a mistake? It’s proving difficult to find the relevant circuit diagram or information on this specific vehicle. I’ll keep searching.

Seems to me that there would be some sort of interlock with the radiator fan. If the ac is running the likely so should the fan with exception of perhaps the condenser pressure being low based of a transducer or pressure switch.

Alas, the troubleshooting I performed initially missed a key piece; I had the fans misidentified. The Radiator fan is working great, the Condensor fan is not. Both fans should be running with A/C engaged and only the Radiator fan is. I realized my mistake this morning and confirmed I have power, when called for, all the way up to the fan, which spins freely, hence bad fan motor is the updated diagnosis.

Thanks everyone. I’ll replace the fan and I bet it’s a whole lot better :wink: