Had the coolant replaced February when I replaced the thermostat. Left work tonight, 43 degrees out, and over a 15 minute drive, only blew 43 degree air at me the whole time.

Anyone think the heater core could be clogged from coolant sediment or just be going bad?

 

What does the temperature gauge do? does it go to the middle and stay? have you let it run more than 15 minutes? does the temp gauge fluctuate?

 

the temp gauge reads correct. I've let the car run for over a hour and still no heat.

 

Does it smell like coolant when you're running the heater?

You can check your heater core flow with your hand on the hoses (they are located in the middle of the firewall behind the engine) They are two small hoses (maybe covered with plastic), one is in and other is out...I THINK the one on the left is IN and the one on the right is OUT, when you're looking at the engine from the front, I don't remember....the IN will have a STRONG flow and the out either none or a trickle, then you'll know your heater core is bad....you can also TRY to flush it out with a garden hose.....I had luck doing that ONCE.....otherwise, to replace the heater core, it takes about 4 hours to remove the dash to get to two screws that hold the heater core in...also, your AC will have to be discharged and recharged to do this job.....

I'm attaching a photo of what those two hoses look like, after the plastic cover is removed (that is if your cover is still on...).

 

Thanks, going to try flushing. Probably going to flush all of the coolant at the same time. start it fresh

 

This is some of the sediment that came out of my heater core. It blows hot for a little bit, but not for long. I think there is still more in there or just air that is not getting pushed out of the core. going to try more tomorrow
sediment.jpg?t=1288651425

 

If you're going to flush it, use water as hot as you can make it and put CLR in it as well. Let it sit in there awhile to really work - it's amazing how much more crap comes out that way vs just using cold hose water. Flush it in both directions too.

 

Devil, What is CLR?

 

They sell it at Lowes in the plumbing chemicals - it stands for Calcium Lime Rust, and is meant to break down mineral deposits and other crap. Given that most people top off their coolant with hose/tap water rather than deionized water, many of those compounds in the house water end up in the car and can clot up sections of the heater core (especially the core since that part of the system is in parallel to the majority of the cooling pathways and is relatively passive. Compared to the radiator and other portions, very little fluid flow goes through the heater system and that "still water" is conducive to buildup and calcification. Hit it with CLR to break it down and use hot water for good measure and you can get a lot out of there that cold tap/hose water won't break free. You can put boiling hot water 2/3 full in a 2-liter bottle and add CLR. Put your inlet hose into it and the outlet hose into an empty 2-liter and squeeze the bottle to push it into the core, through, and out into the empty bottle at the other side. Flush it back and forth that way and bleed the hell out of it and you can fix clogging that a garden hose won't even touch.

 

CLR is a Calcium Lime and Rust remover. Works really friggin well and is environmentally safe. Can be had at any hardware store, wal-mart, or target, places like that.