Turn Heater on-Loud Squealing noise on pass side-No heat

Hello Everyone,

This is my first post. I am the proud owner of a Red 99 Coupe. I purchased it used from a dealer about 9 months ago. At that time when I turned on the A/C I heard a very mild high pitched noise from the pass side. I also noticed when the A/C was turned on water would flow into the pass side until I turned off the A/C.
I put the car away for the winter. I got itchy yesterday and took the car cover off started the car. All was well until I turned the heat on about 10 munites later. I heard the loudest high pitched noise that varied in sound. Now I have no heat. Nothing comes out of the vents.
I would appreciate if some of you masters out there could help me. Thanks in advance.

Regards,

Jeffrey

[vette-dude]

This is just a guess but the last time this happened to me it was the squirrel cage fan on the heater/AC motor had broke where it mounts on the shaft. Also the motor itself may have gone south as they will sometimes squeal before they seize up. You said you had water coming into the pas compartment? If so then you have a heater core with a hole in it or a bad heater valve. The cause of the heater fan going bad could be something has fallen down the defrost vent ( pen or pencil left on dash) and has jammed the fan blade. This is all speculation based on past experiences in older vettes and others. Good luck.

Randy

[Stan The Man]

Your problem may also stem from a blocked AC drain pan outlet, which emerges from the firewall apparently near the RH cylinder head [don't burn your hand] I must admit I cannot even see mine from the top. It is a rubber tube about as thick as your finger, with 90 degree elbow at top end. Condensate from the AC will accumulate and overflow into the passenger compartment in event of a blockage. Also check the Air Intake Plenum drain tubes as these can block with debris. There are two on the LH end of the firewall and they are about 1.5 inches in diameter with rounded end which has a split. There is also one on the RH end of the firewall, C4C5specialist says this particular blockage accounts for 90% of related problems. It emerges from the firewall and disappears back into the wheel area, the outlet is accessed by removing the inner wheel fender access panel. If these plenum drains become blocked rain or washing water will build up in the plenum and overflow into the heater via the fresh air inlet door, with similar effects as the AC problem. I am not sure exactly how debris can get into the plenum as my 2000 has gauze with fine mesh, perhaps some earlier vehicles have different fresh air intakes? Lift the hood and inspect, using a torch if necessary looking through the fresh air intake grill near the wipers, to see if there is any evidence of water laying in the plenum. Check after washing the car or heavy rain, if its there act.

This shows the two drains on the drivers side:



This show the approx position on the passenger side:


Try doing a ‘search’ using the word ‘drain’, ignore the obvious dead ends like ‘oil drain’ and you will find much information on this subject. It is not confirmed but these checks should be made during normal service, but I can believe that they would be missed, especially if panels have to be removed. The AC drain is difficult to access some say from above others from below, ideally it needs removing in order to flush out properly and to access the drain tube to tease out sediment with a pipe cleaner or similar.

Worse scenario is the dreaded computer bathing which can lead to big bucks going down the drain. Again there are many sorry tales about this if you care to search.

The end line is do these checks yourself, I like spending time with my special car.