I have a 1998 cadillac deville and the heater blows cold air. The antifreeze is fine and the last time i drove the car the temperture reading was 212 degrees. Any ideas on what the problem could be? Thanks Jeff

I own a DeVille. Check your large hoses to see if they are warm when the caddi is warmed up. Do you have blowing air from your fan? If not, check the fuses and swap relays under the hood with each other to see if it a relay. You may have a bad blower motor, but check the relays and fuses first. If all those check out good, replace thermostat for warm heating. This will not effect the cold heating. Last and very important. Are you losing antifreeze? If you are, you may have a blown head gasket. 4.1Ltr engines are known for this seeing that most people do not change their antifreeze often enough. Good luck. email me at tvandenhoy@hotmail with your diagnostic results.

Bad heater core? Blocked, When is the last time you flushed the cooling system?

Could be a fuse or the ac control module. I would check the fuse first.

Leave rad cap off, and start engine from cold, top up coolant and make sure your heater is on, and run engine until operating temperature reached, and make sure you allow it to run for a while after reaching operating temperature. Rev engine slightly for 5 seconds or so, every once in a while to help bleed air out. Check heater as your doing this and you should feel warm air. Once heater is working good, top up coolant in rad & bottle if you have access to both, then put all caps back on, and you should be o.k.
Just be sure to check coolant level in bottle from time to time, and top up if necessary.

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

this problem is caused by a defective air temp control blend door motor, this door and actuator motor is located inside the dash between the heater core and the AC evaporator core, it shifts airflow through the heater core or the AC core or mixes or blends the two for the desired temp at the outlets, the motor will have to be replaced. This is a very common issue.

The heater mabey cause from many things easy to check are your thermostat. heater core or low antifreeze

Hi,check if the compressor clutch is engaging,if not check the conection at the compressor if ok check,fuse ,or relay ,if those are fine and the commpressor is engaging,check freon presure ,may be too high or low, if this is the case ,correct the problem and disconect the negative cable from the battery for a minute to reprogram the sistem..C1

There's a blower motor (fan) under the hood and up against the firewall near the center of the car that takes some work to remove. It has gone out in the last 2 of my 4 Cadillacs. Turns out if you're not real careful with the positioning of the spark plug wires they will brush up against it, and if one of them gets cracked or brittle it will "arc" and short out the blower motor. The a/c compressor should still come on (you'll hear a click when it engages) but you won't get any air blowing into the cabin, hot or cold.

The part was like $200 stock (year 2000 prices) and it took about an hour to remove it. My Caddy at that time had this damn strut bar going across the engine bay which we eventually removed to get to the blower motor.

heater radiator blocked or partially blocked,drain antifreeze and save ,remove the inlet and outlet pipes for teh heater and flush in both directions repeatedly .brown rust should come out,if not a lot comes out then fit two pieces of pipe about a foot long to heater unit pipes and mix some caustic soda and pour in one pipe with a funnel till it comes up in other pipe leave for a while then flush again and you might need to repeat this two or three times