Car overheating no heat coming from vents just cold air

SOURCE: 1998 caddy sts over heating and blowing cold air when heat is on

sounds like it might be low on coolant. Low coolant levels will stop the flow and circulation to the heater core, and also might be the cause of overheating

Kelly

• 3740 Answers
• Posted on Jan 27, 2010

SOURCE: car overheating, blows cold air out vents, changed

A couple of things to check because as you describe your symptoms you actually have 2 problems

1. No heat from vents.

Sounds like the heater water flow valve cable is kinked disconnected or the valve itself is stuck You will need to follow your heater core water supply lines to find the valve usually to the right of the center console in the ducting area / large plastic housing for heater and AC internal coils. If the valve works then there is a possibility that the heater core water supply lines have been bypassed on the engine side of the firewall with a coupling due to a leaking heater core. And l;astly the heater core could just be clogged. (quite rare!!)

As for the overheating engine after all of the work you have done.. Perform this simple test.

1. remove radiator cap
2. have someone else start the car
3. watch for water coming out of the open radiator cap area DURING start...
4. have person in the car rev engine gently 2 or 3 times. No need to exceed 2000 RPM. If water rapidly flows out of the radiator during engine revs.. you have some major engine issues.
If it passes all of these checks then the only thing left is improper hose connections on the engine side of the firewall and or a hydraulic water lock in the block that should clear itself by starting and stopping the engine many times with the radiator cap off.

SOURCE: air conditioning and heating

The vacuum line on the drivers side of the intake manifold just below the throttle body fell off.

SOURCE: overheating 97 dodge caravan sport

i had the same problem, i dont remember the name of the piece but its mounted right in between the driver side headlight and the radiator. its a relay that turns the fans on when the car gets hot. its mounted on the body of the car. there should be wires leading from the radiator to the piece im talking about.... good luck I also paid about 35 dollars for the piece

SOURCE: two vents blow cold air and two warm air inside

check the 2 cold vents see if they r blowing out less on high than the other. check ur vent hoses between the vents it might be disconnected and only sucking in cold air. that will get u started on a sollution. some vehicles vent hoses tend to run out side the fire wall in the engine compartment.