7

I have:

  • replaced the thermostat about 10 times,
  • back flushed heater core and flushed cooling system out about 10 times,
  • replaced water pump,
  • intake gasket,
  • blend door,
  • mode door,
  • actuators,
  • HVAC control head,
  • blower resistor,
  • blower resistor pigtail,
  • radiator cap,
  • cooling fan relay,
  • and heater core.

Yet I still have no heat in this car. This is something that I have been battling for 4 years now. We have also ran block test to check for the head gasket and it comes back good.

I DONT KNOW WHAT ELSE TO DO!!!!! $2,000 in repairs and still no heat. At my wits end.

  • 4
    can you confirm that the blend door actuators actually work? how about the heater hoses, are they both hot with the engine up to temp? is this automatic or manual hvac? does the blower motor work? is this intermittent or does it always not have heat? – Ben Dec 15 '16 at 12:31
  • 1
    It would be good if you could add details, answers to all of the questions that @Ben asks will help us to help you. We want to know what works, and what doesn't and if you can also tell us what lead to each of the repairs. For example do you remember if the blower fan was stuck on high or not working at all before the resistor was replaced? Did it work after that? – dlu Dec 15 '16 at 12:57
  • 1
    Was all of this done by the same mechanic? – stannius Dec 15 '16 at 23:17
  • A simple reason one of @ @Ben's suggestions: I had a flimsy plastic clip fail, which meant that instead of pulling on the blend door lever the cable to the control knob just bent. This was made worse by the blend door having been left in the full-cold position for a entire hot summer so it was slightly stuck.The fix was a cable tie to the back of the dash. – Chris H Dec 16 '16 at 9:24
16

It sounds like the approach to solving your problem so far hasn't been very systematic or "evidence based" – at least the list of parts replaces suggests that the people working on it have been using a "shotgun" approaching, replacing parts in hopes that one (or more) of them will solve the problem.

Start off by doing basic checks:

  1. Is there hot water available? It could be that your engine is not coming up to operating temperature. Check the temperature gauge if you have one and also the hoses going to the radiator. After 10 or 15 minutes of operation the hoses should be very noticeably hot.

  2. Is there power to the heater controls? Does the fan run? Check all of the fuses related to the heating system – especially if the fan or the heater controls appear to be not working.

  3. Do the heater controls seem to be working (can you hear the blend doors move when you change the controls, does the fan run, do the heater hoses change temperature when you adjust the temperature control)? Learning which controls work (and maybe which don't) will help you to isolate the problem areas.

  4. Is hot water moving through the heater core? Check to see if the hoses going to the heater core are getting hot. They will be cooler than the other cooling system hoses if no water is flowing through them. If the hoses do not seem hot, there are two likely possibilities: one is that the cooling system has air trapped in it that is preventing hot water from getting to the heater core, and the other is that something, perhaps a kinked hose under the dash, is restricting water flow through the heater core. If you squeeze the hoses as if to close them off while the heater is "on" you may be able to feel water moving through the hose.

  5. Check for obstructions to the air flow through the heater – one of the few things in the heating system that I don't see on your list is the cabin air filter, so confirm that it is not plugged. Also confirm that when the fan runs you get air movement through the vents.

Finally, at this point it would be wise to assume nothing. So much has been done (and seemingly without a methodical approach) that it is possible that there are compounding errors or problems. Run through the list in order eliminating possible problems. Most of them are checks that you could probably make yourself, then when you isolate a potential problem area you could either ask another question based on your findings or take that information to a mechanic. When the mechanic does work, ask that s/he explain the thinking and evidence that went into the work.

  • 2
    You missed the first step: 0. Is the temperature gauge reading normally and is the car radiator getting hot? But this is the right way to go - don't keep swapping parts at random ("10 replacement thermostats" is just crazy), find out how far the heat is actually getting to where it's supposed to be, then figure out what is stopping it getting there. – alephzero Dec 15 '16 at 16:55
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    @alephzero isn't that (essentially) point #2? – GalacticCowboy Dec 15 '16 at 17:37
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    Depending on the car, replacing the blend door actuator and/or switches can actually reverse the heat settings. I know this happens in early 2000's Jeeps, but maybe it happens in a Chevy. TLDR; Try turning the temp-control knob to COLD and see if your heat works. I know it's weird, but what could it hurt? – FireSBurnsmuP Dec 15 '16 at 18:14
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    @GalacticCowboy - it is, but its the easiest thing to check so should probably be first. – Batman Dec 16 '16 at 7:08
5

Any chance the coolant wasn't filled completely and burped? The heater core is the last thing in the system getting coolant as it sits the highest.

Also make sure there isn't any air trapped in the system. Use the bleeder screws (open them slightly) and squish the hoses.

As has been suggested elsewhere, you told us all the repairs that were done, but not why. What led to each repair?

0

Make sure your thermostat is not upside down. Make sure your heater core is not clogged and that the hoses are on the correct pipe going in and exiting the heater core.

  • What would happen if the thermostat was installed upside down? – dlu Dec 16 '16 at 10:54

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