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Where Is The Low Pressure Port For A/c On '98 Mazda 2.0


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#1
TechMan100

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I have found two R134a ports but I don't know for sure which one is the low pressure port.
I am trying to recharge my A/C unit.

One port is on a canister (accumulator??) with a black cap that is connected to the firewall. This port fits the
nozzle fitting on my R134a recharge can but the gauge immediately reads around 72psi. When I turn on the
compressor it drops to about 45psi and then climbs back up into the danger zone.

The other port has a blue cap with an 'H' marked on it. It is on the smaller diameter line of the two that appear
to go down to the condenser. My nozzle fitting is to small for this port. I'm assuming that this is the High pressure
line.

I was thinking that it just needed a recharge because nothing at all has been done to the A/C system for at least
5 years. It won't start cooling when at idle - gotta drive for a bit to get it cooling. It seems that the faster I drive
the faster it cools which tells me that the condenser is working.

Any suggestions as to why the psi would be so high, and I do if fix it.

Thanks for any and all help.

#2
Raziel

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  • Car: 1997, 626 LX, 2.0L, Auto

I have found two R134a ports but I don't know for sure which one is the low pressure port.
I am trying to recharge my A/C unit.

One port is on a canister (accumulator??) with a black cap that is connected to the firewall. This port fits the
nozzle fitting on my R134a recharge can but the gauge immediately reads around 72psi. When I turn on the
compressor it drops to about 45psi and then climbs back up into the danger zone.

The other port has a blue cap with an 'H' marked on it. It is on the smaller diameter line of the two that appear
to go down to the condenser. My nozzle fitting is to small for this port. I'm assuming that this is the High pressure
line.

I was thinking that it just needed a recharge because nothing at all has been done to the A/C system for at least
5 years. It won't start cooling when at idle - gotta drive for a bit to get it cooling. It seems that the faster I drive
the faster it cools which tells me that the condenser is working.

Any suggestions as to why the psi would be so high, and I do if fix it.

Thanks for any and all help.

Low pressure port is the smaller one, which would be the first one you mention. The other one with the "H" (should also be bigger then the other one ) is the high pressure side. The low side should be between 30-40 psi. If you were low on freon it wouldn't be that high, so I would say it's not that. And since you said the A/C hasn't been worked on for 5 years, it's not over charge then. It can be the expension valve(stuck), compressor(internel failure), dryer(clog). The only other 2 parts on there is the condenser & Evap. Core. One is easier then the other, evap core is behind the dash between the passenger & center dash. Condenser is in front of the radiator. If you recover the A/C system, disconnect both of the lines for the condenser & blow air in the inlet line & see if air comes out of the other one. Should be the same force of air coming out as it is going in. If not, you need to replace the condenser.

You might want to get the readings for the high side as well, could help pinpoint what is causing the problem...

#3
twiztedtorque

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There's a step that you're missing. The port on the canister is the correct port.

What you want to do is this:

1. Look on the drivers side of the canister for an electric connector. Unplug it.

2. Get a paper clip and make it into a U.

3. Jumper the 2 points on the connector. (the wire end, not the reciever on the canister)this will keep the compressor on constantly.

4. Connect your recharge bottle to the port on the passenger side of the canister.

5. Start the car and and turn the a/c controls to max(speed to 4, temp to full cold, a/c on, recirc on)

6. Refill the system till the needle on the bottle indicates that you're done.

7. Turn car off, disconnect the bottle, re-cap port, remove jumper, and reconnect electrical connector.

8. Restart car, roll all windows up and leave the a/c controls the same. Leave running for 15-20 mins, and check temp inside.

9. Feel the great A/C goodness. :biggrin:

#4
TechMan100

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Thanks for the replies. I'll post an update right after I give it a try.




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