a/c question - increase in vent temp the day after new charge

[Hoppe]

A quick question on a/c (don't shoot me). Yesterday I completed installing a fender condenser and charged the system. I got low thirties at the vent on an 80 degree day. Now today it is only 4 degrees hotter outside and I get about 48-50 vent temp. I assume I need to look for a leak. Could it be anything else?

Thanks,
Hoppe

[Pazuzu]

Put the gauges back on and see what the numbers are like. Or, get a static pressure and see if it compares to the ambient temp.

You might even be able to hear a leak, get it up to working pressure then shut the car off, 240psi will hiss audibly.

[kuehl]

Assuming you evacuated the system and charged it properly, and you have no leaks.....you need to compare apples to apples and record all your data.

Windows up, fresh air controls in the dash to the left, heater box valves closed,
testing pressures at "idle", deck lid resting down on its stop, service hoses to the right of the compressor pulley, let system run for at least 5 minutes, fan speed 2, thermostat max cold, and at idle:
1) Ambient temperature around the car, and is it a sunny day or cloudy day.
2) Low and high side pressures
3) Vent temp from the center vent

Then drive the car, after 15 to 20 minutes 35-45 mph, what is the vent temp at fan speed 2, what is the outside air temp.

[Hoppe]

Looks like I do have a leak. I used UV dye so I was able to put a black light on it tonight. It is at the hose connection coming out the the original condenser. The last connection I made when hooking everthing up after flushing the system. Used a new O-ring and tightened it down snug. I guess I will need to get the system evacuated and try again. Good news is the rest of the sytem appears to be leak free.

[kuehl]

Good job solving the issue.
I forgot to torque my cylinder jug allen bolts last month.

[Hoppe]

Thanks; however, I will consider it solved when it does not leak. Not sure why it does, unless over tightening could have caused the issue. I don't think I lubed the 0-ring either so may that's it.

[kuehl]

Disconnect the hose fitting from the original condenser (use 2 wrenches, one to hold the fitting on the condenser and the other to turn the nut on the hose fitting; this is for readers).

Remove the o-ring.

Inspect the "bubble" or "bead" on the hose fitting that backs up the o-ring when the nut pulls fitting into the condenser. The shape of the bubble bead should have a round form on its outer edge. If it is flared back toward the nut the fitting was over tightened and o-ring will not seal.

Inspect the o-ring seat inside the bore of the condenser fitting to insure there is no debris or corrosion.

If you get stuck give us a call.

[86 911 Targa]

Others may "chime" in, but I don't think that
pulling a vacuum with a 1 1/2 pump pulls
the oil out of the system.

G.

[Hoppe]

Which raises a good question. If I evacuate the refrigerant and open the system at the point of the leak, do I need to reflush and then re-oil the compressor or do I just need to close it up and pull another vacuum?

[kuehl]

If you need to remove the refrigerant and fix the leak, depending upon what you fix you may or may not need to add replacement oil.

Examples:
Compressor replacement 2-3 oz max
Drier 1-2 oz max
Evap 2-3 ox max
Deck lid condenser 1-2 oz max
Front condenser 1 oz max
Replace an o-ring nothing
Replace evap to compressor hose 1-2 oz max
We can go on and on

[kuehl]

The oil is a liquid that won't evaporate under negative pressure.

The only oil that typically leaves the system on a 911-930 with a denso or 507 is oil near the suction port of the compressor. If you just filled the compressor with oil you are gonna have some flow out, maybe 1 oz max (gravity), if the system has run with oil for a while ... less than 1/2 oz might flow out.

[86 911 Targa]

Originally Posted by kuehl

If you need to remove the refrigerant and fix the leak, depending upon what you fix you may or may not need to add replacement oil.

Examples:
Compressor replacement 2-3 oz max
Drier 1-2 oz max
Evap 2-3 ox max
Deck lid condenser 1-2 oz max
Front condenser 1 oz max
Replace an o-ring nothing
Replace evap to compressor hose 1-2 oz max
We can go on and on

email sent.

Gerry

[kuehl]

Originally Posted by 86 911 Targa

email sent.

Gerry

No spam Gerry