Honda Car Forum

I have a 99 TL, runs great, no problems, except the air from the heater is turning cold suddenly while driving. I can get it warm again by turning temp right up. No connection to A/C on or off, replaced water pump, heat servo motors working fine. Heat will work great while parked, idling, then upon acceleration turns cold sometimes. No connection between problem and outside temp.Anybody got a thought for me?
Thanks for any help.

check you antifreeze level. You might have a bubble in the cooling system

Thank you, I'll check, but I'm sure that's not it. Maybe a plugged heater core ? Is there one in an Acura? Antifreeze is in good condition, is changed every 3 years.
Thanks for replying.

Yes your car has a heater core. That is very strange I have never heard of your problem. I would not think you heater core would have that problem since you change your coolant all the time. maybe there is a problem with the hvac controls. I would take it in to dealer. Good luck!

Thank you for the reply. It was at the Acura dealer and they could not figure it out, which is why I got on the net. I know it's a strange one, checked the Honda dealer etc, and they'd never heard of it either.
Thanks for taking the time, much appreciated!