Post by
bmlawless »
https://forums.nicoclub.com/bmlawless-u85265.html
Wed Jan 09, 2008 11:22 am
My experience with any vehicle has been that low coolant levels and air bubbles can be diagnosed when you notice that you get cold air when stopped at lights or idling and warm air out of the ducts when accelerating.
If you are consistenly getting cool air, especially if your air blows cooler with colder outside temps, your engine's thermostat may be stuck open. In this case, the coolant is never getting the chance to heat up. If you are driving on the freeway and your engine temp gauge is always in the low range, this could be another indicator of the problem.
The good news is that bleeding the cooling system and replacing the thermostat are both cheap and easy jobs. When you bleed the cooling system, replace the thermostat too. It's a cheap fix.