mrg

With the AC up and running the air coming out of the vents reads 46 degrees. Seems the air should be colder than this. .. How cold should AC air flow be?. The AC package is a Vintage Air. Thanks
John

Powershift

Factory specs are around 38-43 F at the right duct. This is from the Chevrolet Service Manual.

Larry

65GGvert

That is excellent. How much colder would you want it to be?

dplotkin

Colder than that. The ideal is 40 to 42, depending on head pressure which depends on ambient temperature and air flow over condenser, all other things being equal. Into the 30's and you risk a frozen evaporator which could lead to sending liquid refrigerant back to the compressor.


You want to gauge system performance on high and low pressures, not the vent temp. Also keep in mind that A/C systems don't generate cold, they absorb and remove heat. So if a car leaks a lot of air through convertible top & weather seals or vents, you may never see an improvement in vent temp.


Put a set of gauges on it and let us know what you have for pressures, noting the ambient temp when you do so.


Dan

Frankie the Fink

93* in Orlando summer after about an hour on the turnpike at 65mph.
Air temp is 41*...it actually dipped to 40* a couple of times but I didn't catch it.

'63 coupe. Coolant temp hung right in at 175*...

mrg

It would be great if the outlet temp could get down to 41 degrees like Frankie's AC shows.
My car is a convertible. There are some air leaks around the top, side and bottom rear of the windows. What Dan mentions might explain what's going on.

I'll need to acquire the gauges to see what the pressures are. Maybe as an experiment the air leaks could be taped over to see what effect it might have. .. Thanks, guys.
John

DUB

Outside air leaking in and radiant heat from the firewall and transmission tunnel/floor boards DO make a difference IF the objective is getting the inside of your car so cold you can sell ice cream out of it.

What Dan wrote on post #4 basically 'says' it all.

DUB

Frankie the Fink

Here are the Vintage Air test specs for pressure and nozzle temp under a specific set of test conditions.

mikem350

A slower fan speed will show lower temps. As will more airflow across the condenser, like when driving as compared to not moving

Westlotorn

Most AC instructions I have read advise testing at 1,200-1,500 RPM, not at idle, and with a fan blowing on the condenser. In those conditions I have seen high 30's, 37-39. At idle and with no fan it will rise to upper 40's. Line pressures vary quite a bit based on outside air temp but there are charts and formula's that can give you a pretty close guide to check against.