1988 BMW 735I Defroster blows hot air... I getting a sunburn
The defrosters blow hot air on the windshield all the time. Its so hot I feel like my face is burning. Not really that bad but bad enough I have to keep the windows open even when its cold outside. Is it a fuse? Is it a stuck door? Is it a sensor? Is it a ???
Any information will be helpful. Due to limited funds I must repair myself.
Re: 1988 BMW 735I Defroster blows hot air... I getting a...
The Heater Control Valve has failed. It defaults to full defrost mode when it fails and blows hot air even when the A/C runs. Replacement part is $105 ...google Autohaus AZ for online parts ordering. BTW...HCV is located in the engine compartment right in front of the driver position in the corner by the firewall and inner fender...you'll see small coolant hose running to it.
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Not likely. 20W-50 is usually used in high rpm engines in warm to hot climate. By any chance is your windshield defroster on? When the defroster is blowing your air conditioner compressor is engaged which pulls the moisture out of the air so you get HOT DRY air blowing on the interior of your windshield
Can you feel (with your hand) a difference in the air pressure blowing in the driver's side windshield vent and the passenger's side vent? If so, I'd bet that something has fallen down the defroster vent and is partially blocking the channel on the driver's side. You could try taking a length of fairly stiff wire or a straightened wire coat hanger and sliding it down the driver's side defroster vent to see if you can dislodge whatever is down there, but you can't get the obstruction completely out that way. Removing the defroster ducting is not a simple task, but an experienced auto technician can do it (parts of the dash board have to be removed along with (possibly) the radio and anything else in the center portion of the dash. Good luck.
your blend door motor IS your defroster problem , as it is needed to direct heat mixed with the ac to properly defrost the windshield . if when you change your blend door motor and the problem still exsist , then youy have a defective blend door package , meaning one of the doors are faulty , which could get very expensive to repair , good luck !!!
feel the two hoses going into and out of the heater core. they both should be hot. if one is cold the heater core is likely plugged. you can try flushing it out to see if you can restore flow to the heater core. if they are both hot the thermostat may be sticking open tho you should have a limited amount of heat. also confirm that the vents are operating as they should be.