A/C question

[ED C.]

the A/C on the 88TE is not really cold at idle or low RPMs. At highway speed it runs cold and cools the wagon down. What is this telling me? Low coolant, slipping serpentine belt etc.?

EJC

[4uky]

Auxilliary fans not turning? Just open the hood with the car running and a/c on and see. I'm guessing they're not.

[shailey]

Ed,

It sounds like the refrigerant charge could be low. Higher engine speeds mean higher compressor speeds, ie: more coolant circulating. Also higher road speeds means more air moving through the condenser, leading to better heat transfer, (and cooler air flowing from the dash vents).

Conversely, low engine speeds and low air flow through the condenser, (ie: car parked and idling), means less coolant circulating and less heat transfer, (warmer air flowing from the dash vents). I would try a recharge provided that your aux. fan is working.

Good luck,

Steve
2002 W210, 53K

[Ron in SC]

At highway speed it runs cold and cools

What is the center vent temp when it cools fine?

[ED C.]

Aux fan is working. I was thinking low charge. I will check the center vent temp. I will check the charge and add 134 if necessary. Of course now I am wondering if the evaporator is leaking again!

Frankly I have never been satisfied with the vent temp of the A/C even after the evap, compressor and vac element replacement 3 years ago. Not near as cold as the A/C in my 95 Saab or other cars I have been in. It never gets "ice" cold, just marginal. I have always chaulked it up to the system being converted to R134 by the previous owner.

Thanks for the info.

ED

[Ron in SC]

I checked the center vent temp of my car while driving on the interstate. Outside temp indicated by dash was 92 degrees.

Center vent with fan on high was 50 degrees and with fan on low it was 42 degrees.

Vehicles is 92 300TE. I installed new evap, 6 elements, and receiver/dryer a few months ago. Also my system is R134a converted.

[xan021]

my 95 e320 has the exact same problem. I took it to the shop yesterday and they told me the evaporator is leaking. $1k just for labor. Hopefully yours is something else.

[ED C.]

Just to follow up. I checked the charge and it was at the low end (25PSI) I added R134 to bring it up to 40 psi. cooling performance is a little better but not much. I will check the charge again tonight to see if there is a leak.

[Ron in SC]

I checked the charge

To rule out undercharge or overcharge it would be best to evacuate system and charge by weight.