C280 1994 A/C System
 

Hey,

Is it possible that when a motor overheats that this would cause the freon to disiminate out of some pressure release valve such as found on the compressor due to high heat and high pressure?

My A/C had been working well until I had repair done to the heater valve under the hood up, on the passenger's side near the computer.

The symptom that I experienced last summer was that it would cool for 2 weeks but then stop. I ran dye in it and didn't detect anything except from the pressure release valve on the compressor. However, the irony of this is that my thermostat was bad and the engine heated beyond the norm. Suffice to say, I replaced the thermostat and the engine is running at normal temperature now. It appears, however, that I lost freon.

Any suggestions?

The valve is like anything else, it can leak. IF the only location you get dye traces is from there, either replace that or the compressor. However, I'd recomend rerunning the dye test and make sure to check the evap (never seen a 202 with a bad one), expansion valve, fuel cooler and the high pressure line from the dryer to the expansion valve. (all of which I have found leaking on 202's except for the evap)





Joe

It's very likely that the heater valve is now not working correctly and adding heat to the system causing the refrigeration effect to be overcome.

With everything running and a/c turned on max, feel of the hose going in and the hose going out of the valve. If they are both warm then the heater valve is flowing heated coolant to the heater core and this is probably the trouble.

If not, then you need to check the sight glass and best approach would be manifold gauges to check a/c.

Good luck,

Thanks guys

I had the heater valve replaced because now it's not in "safe mode" and blowing heat outside the vents.

I will, however, run the dye again and see what comes up.

Can anyone help me with the vacuum line diagram to the switch that lies near the heater valve? I want to make sure they put the right vacuum lines where they're suppose to be.

It's just unusual that the diagnosis is low freon when I can't find any leaks with the last time I ran dye.

Could the evaporator be leaking? :( I hope not.

Jonathan