Air Conditioning Question

[ScottyP]

I have a 1995 C280 with Climate Control and Im not sure if the air conditioning is working properly. When going uphill, speeding up quick, or anytime the car has any load, the fan stops working until normal driving conditions exists. Tried multiple settings, same problem; with recirc on, auto on, fan speed on, etc. Is this normal??

In the past with other cars, this indicated a vacuum leak somewhere. Im concerned because in EC mode, I get alot of heat from the floor vents (as if the heater was on) with temp set the lowest settings.

[jnenad16]

the EC mode is only blower on, but not the a/c(compressor).
as for the first part, can you desrcribe it with a bit more detail? also, does the ac peformance change significantly as well?

nenad

[ScottyP]

Sure Nenad. Basically, with the AC on... the fans go out when I accelerate from standstill or when going uphill (car under load). Question is: Is this Normal ?? Does the car throttle back the air conditioning when the car is under load to provide engine torque or something?

My experience says vacuum leak in the reserve vacuum tank or a line connected to the vacuum tank since the manifold cant supply enough vacuum when car is under load. But thats the fix for chevys, nissans, etc. Does this apply here? Everything on this car is vacuum controlled and maybe I need to look at a regulator somewhere if this is not normal.

When I have just EC on (fan only) and temperature turned all the way down, the front windows fog at the bottom and Hot air comes out of the defrost vents and floor vents.. Its like the heater is on. What controls the heater? Again, my experience says Yes - Vacuum Leak for sure when air is redirected to the defroster vent default position.. But this car have vacuum lines everywhere (doors, trunk, hood, bumper, everywhere!). The leak could be in any of these places..

BTW, My AC is somewhat cold most of time Except on 90+ days in rush traffic. Then its just cool air. Today, it was 95degrees with humidity of 60% made it feel like 105degrees. The AC was working hard but managed to keep me cool as long as I was moving.

Hopefully this explanation was a little more descriptive. I need HELP.. August starts next week, traffic will get worst and I will not be confortable if this continues.. This cant be normal.

[rollinrealbig]

ehh, do what I do - toss a bag of ice over the blow motor!

jk dnt do that. :D

[jnenad16]

the vacuum has nothing to do with the auxiliary fans, they respond to engine temprerature and ac pressure. when the ac is on, the fans turn on when the ac system pressure reaches a set point, in your case I believe its 24bar(or so),and turn off when the pressure drops below 16bar(or so). now, the ac system pressure goes up as you increase engine speed, but due to adequate cooling capabilites of your radiator fan, it should stabilize and the ac peformance(cooling efficiency) improves. so, in these conditions, the auxiliary fans usually work on idle and until the car starts moving, and then they go off.
hope this helps you.

nenad

[ScottyP]

Originally posted by jnenad16
the vacuum has nothing to do with the auxiliary fans, they respond to engine temprerature and ac pressure. when the ac is on, the fans turn on when the ac system pressure reaches a set point, in your case I believe its 24bar(or so),and turn off when the pressure drops below 16bar(or so). now, the ac system pressure goes up as you increase engine speed, but due to adequate cooling capabilites of your radiator fan, it should stabilize and the ac peformance(cooling efficiency) improves. so, in these conditions, the auxiliary fans usually work on idle and until the car starts moving, and then they go off.
hope this helps you.

nenad

Im confused... Why are we talking about the Auxiliary fans? Im not having overheating problems.. Im talking about the blower fans inside of the car.. Thats why you needed a better desciption.. :)

My blower fans inside of the car dies when car is under load; nothing coming out of VENTS (rapid accelleration, from a stop, on ramp accelleration, etc)..
Then once at speed, the interior blower fans return to normal.

Now, is that a vaccum problem or Normal ...

[jnenad16]

oh, my bad, I thought you were talking about the auxiliary fans. :)
the blower is controlled by the ac contol unit and the blower resistor. the vents are the ones controlled by the vacuum actuators. if there was a vacuum leak, the malfunction should be constant, not intermittent.

nenad