Why does my Volvo air conditioner make a hissing noise?
The manual heater control assembly supplies vacuum to the under hood heater valve to shut off coolant flow to the heater core in the cold position of the control lever. The vacuum connection had come off the heater valve, and the free flow of air caused the hissing sound at the heater control.
When do you close the water valve on a Volvo?
[Response] Vacuum to close the water valve is only applied in max AC mode or when the MCC temperature selector is fully cold. This varies according to the type of control system in the car (MCC, ACC, ECC) and the Volvo OEM service manual should be consulted for details of vacuum signals.
Where is the vacuum hose on a Volvo?
Leaking Sound from Under Dash. That vacuum leak is almost certainly your floor/defrost diaphragm. It is on the left side of case just above the accelerator pedal. This diaphragm unit is double acting, i.e. it has vacuum to pull it both ways, blue hose for defrost and yellow for floor.
Why is my air conditioner not working in my Volvo?
You have a vacuum leak which causes the heat vent control to work improperly; Your firewall-side heater water valve was installed backwards; The arrow on the valve points to towards the firewall inlet, not back towards the engine. Control cables from the heater control unit to air mixing doors are maladjusted or broken.
How long does it take for Volvo A / C to warm up?
In this forum you’ll find S40/V40-specific owners asking and answering questions on maintenance, ownership, repairs, tutorials and almost every do-it-yourself thing you can do to save money owning these Volvos. The a/c starts off cold and within 5-10 minutes the air is coming out luke warm.
Why does my car a / C keep blowing cold air?
The AC can be cooling the evaporator coil perfectly but the cliamte control is routing air through the heater or mixing enough heated and cooled air to not give you the cooling effect. In older cars the doors the cliamte control closes and opens were controlled by vacuum actuators.