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Aha! Posted by Ari [Email] (#2847) [Profile/Gallery] (more from Ari) on Sun, 3 Aug 2008 06:27:34 In Reply to: Re: no heat, jj1000, Sun, 3 Aug 2008 04:07:00 Members do not see ads below this line. - Help Keep This Site Online - Signup |
So there was some recent cooling system work! Was there a heat problem before, or was that not checked? With the 9000, it is critical that you put the thermostat in with the venting hole up. It is important to use an OEM thermostat - I've seen problems with aftermarket thermostats, and not all aftermarkets have the venting hole.
The failure mode of the heater core is to develop micro-cracks, and coolant weeps out. Over time the cracks will eventually get bigger, but that can be a lot of time. Core clogging is not as common, and I'd expect the main radiator to also be clogged.
Yaofeng's comment about flushing the heat core is good. Can't hurt. Just don't hit it with super high pressure water - you want the water to flow, not gush - remember those microcracks.
Since you can get cold air and warm air, the air flap is working to some extent. But not a guarantee that it is working fully. I would set the venting up to Defrost, and see if you get any warm air when you set the ACC to warm temperatures. Why? In defrost, the A/C is guaranteed to keep running, because it is used to dry the air. The arm on the outside of the heater box may be moving, but the flap (or flaps, depends on year) inside the box may have broken. It is possible that the warm you feel when setting the temperature up is mostly the AC turning off. The only good way to check it is to get into the heater box, and if you've gone that far, might as well do the Heater Core.
I say there are two approaches. One is to keep troubleshooting - disconnect and flush the heater core, and while you're in the area, pull the thermostat housing off and make sure the thermostat is in properly. The system will self-bleed if there is an air bubble if the thermostat is in correctly. If all that is correct, then the problem is likely the air mix flap inside the heater box, and a new heater box is in order. The HC is right under it, and if the HC is weepy, time to replace it.
OR -Just plan on replacing the HC. You can limp a weepy HC for a few years, or just bite the bullet. You may need to replace the heater box, depending on if it is broken inside, but you won't know until it is out of the car, so plan on a few down days while the part comes in. While the system is drained down, check the thermostat.
posted by 76.243.12...
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