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Car Heating Issues


This post is going to go back a bit.

A few months ago (back during Thanksgiving) I took my 2012 Ford Fusion in because I noticed my car was leaking a lot of coolant, as well as making a “waterfall” sound when I started the engine. I went to get it checked at a service center (non Ford) and was told the Water Pump was bad. I got that replaced, and my coolant had stopped leaking, and within a few days, the waterfall noise had stopped.

A few months later (now in January) and I had started to notice that my temperature gauge was starting to act funny. Whenever I would start the car, the car would heat up fine, and whenever I was driving (especially on the freeway) the temp would stay within normal range. However, once I got off the freeway, the temp gauge would drop slightly, and my heat would begin to decline from the vents.

I just got this checked out today, and was told the heater core was partially blocked, and the thermostat needed to be changed. Awesome… so I authorized this, and got my car back.

I was warned that since they were going to be messing with the cooling system, I would hear the “waterfall” noise again, but it would go away. That I do. But, I noticed my heating is even WORSE now then before I took it in. I am barely getting any heat from the vents, even when I am driving, and when I am at a standstill, the vents will be almost ice cold.

I am unsure what is going on… could it be the air in the system that is blocking the heat, or something else?

Thank you for your help!

Yes, that’s a possibility. I’m not familiar w/the fusion hvac design, but you first want to make sure

  • the coolant is getting as hot as it should be
  • the hot coolant is actually entering the heater core
  • the blower motor is working
  • the vent doors are correctly oriented

If all that seems to be ok, try having the cooling system bled of any air entrapped. In the days before complicated cooling system configurations a diyer could just drive the front wheel of the car up on ramps, open the radiator cap and idle the engine with the heater on max until all the air bubbles burped out. Might take 10-15 minutes or so. But you car’s cooling system is more complicated I expect, so best to follow Ford’s procedure. If you can find a shop that has the Ford vacuum assist gadget for cooling system bleeding, that’s probably the best way to do it.

It seems like the first step would be to contact the shop that did the recent work and tell them your problem .


I’ve never noticed that to go away by itself on any of my vehicles. If I hear that noise I know there’s air still in the cooling system, and it needs to be re-bled. But maybe on newer vehicles they provide a path for the cooling system to bleed itself if there’s only a little air left.

Sounds like the cooling system was low, that is what causes the noise and lack of heat. Did you check the coolant level before taking the car in to replace the heater core?

The engine may have been damaged by operating with a low coolant level when the water pump failed resulting in reoccurring coolant loss.

The issue is AIR in the system… Look up how to “burp your cooling system”…You are trying to purge any air pockets as these are not welcome.

We have written many volumes on the subject and its a similar process with every vehicle… The main difference is when a mfg provides you with a bleed screw/nipple or not… but neither case is hard to resolve. This assumes you have zero coolant leaks…any leak of coolant will be replace by an equal displacement of air… so no leaky…no air will be actively entering. Once the leaks are dealt with… you are on to the burping process.