Hi guys! I’m having a strange issue that’s I’m not sure of! To start off I’ll give details, my car is the 06 TL base with about 194k on her. Basically I have this issue where the car gets to temp and doesn’t overheat or anything but when I turn the heat on it blows cold until I get on the road. About 2-3 miles in the heat kicks in and strangely that’s also when the heated seats kick in simultaneously. Maybe it’s just coincidence tho. Anyways the issue is persistent. I’ve also had a issue w the serpentine belt, I’ve switched belt 3 times and swapped out the tensioner and idle pulleys but when I turn the heat/ac on it squeaks and when water or liquid hits it, it SQUELLS like very loudly. I added that last part in case that has potentially anything to do w the heat issues. I’m planning on doing a heater core flush but I’m not sure that will even do anything.

 

Had it on my RSX and the dealer said most common reason is the engine thermostat going bad and not letting the engine warm up enough before running the coolant through. Best way is to check the temp guage (assuming your TL has one) when the heat comes on driving, and seeing if it never hits that hot while idling after startup.

Could also be the heater core if the engine properly gets up to temp.

 

well it only blows cold air when I idle and leave the car to warm up even at the right temp it doesn’t blow warm until I actually drive which I guess is the coolant going through system as it’s warm enough to move better?

 

The logic is that if the thermostat circulates coolant at too low a temp then at idle it cools too much and the engine never gets warm enough to heat a cabin. (eg: the coolant should be too strong at idle, which is why these thermostats exist).

And if the car is revving at driving speeds, the coolant piping is sized to keep the temp from overheating but it will be much hotter than at idle.

If you know the specified temp of the engine thermostat, then testing if your engine is idling long term below that temp will be a good sign that the thermostat is bad. If the engine is idling at the specified temp, then is probably something else (eg: look into the heater core and/or stuck climate control mixer valves.) I have no firsthand knowledge of which breaks more often, only a tech at a pretty trustworthy dealer saying what he more frequently sees.

 

Apologies for the dumb question, but have you checked your coolant level in both the radiator and reservoir? Any coolant leaks?

 

I have, that’s not a dumb question! I happen to think it’s the coolant tho cause of the heater core but I’m not sure.

 

"when water or liquid hits it, it SQUELLS like very loudly"

Does your TL have the splash plate to protect the area (where serpentine belt is) from taking a splash of water? A friend was missing theirs and when traversing a large puddle in the rain it would splash water all over the belt causing it to squeal. Next then the AC compressor would sense it is not rotating and shut down. Then the windshield would fog over since the AC was not drying the humid air.