2004 Volkswagen Passat No heat!

BASKETBALL937

MEMBER
2004 VOLKSWAGEN PASSAT
1.8L
4 CYL
TURBO
FWD
AUTOMATIC
117,774 MILES

I have a 2004 vw passat. Car does not overheat or run hot and the ac works. It's recently started getting cold and I want to use my cars heat. I attempted to use the heat the other day and the heat never gets hot. The most it gets is luke warm. I don't know where to start looking, any ideas? I have searched forums and eveything but haven't found a starting place.

1 Reply

CARADIODOC

MECHANIC
33,916 POSTS

First look at the temperature gauge on the dash, if you have one. Is that in the normal range? If it's lower than normal, the likely suspect is the thermostat is stuck open. You can verify that first by feeling the upper radiator hose after driving for a while. It should be too hot to hold onto for very long. Your mechanic can also connect a scanner to view live sensor data. The coolant temperature sensor will be displayed in voltage and degrees. It should be around 190 to 210 degrees Fahrenheit. If it's closer to 160 degrees, the air from the heater will not be hot enough.

Next, if everything points to the coolant temperature is acceptable, feel the heater hoses. Those also should be too hot to hold onto for very long. If they are not, but the radiator hose is, suspect a plugged heater core. That can usually be cleared by disconnecting one of the hoses, then running water through it from a garden hose.

If the heater hoses are sufficiently hot, but the air from the heater is not, that points to an actuator or temperature door problem with the heater box. That can get real involved and is best left to a mechanic who specializes in air conditioning and heating systems.