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Hello everyone thank you for the answers, I have decided to switch my mechanic as he may be incompetent.. I told him the heat was STILL NOT WORKING, and his answer was lets replace the thermostat AGAIN(3rd time) and he wanted me to pay again! I said screw it and decided to bring it to another mechanic.
After reading everyone answers on it being the heater core, I am more inclined to explain to the next mechanic to please check there and that my thermostat has been changed already.
Question though, the aftermarket thermostat I have installed, should I switch that out and buy another OEM Honda one, is it bad to keep the aftermarket thermostat in my civic?
The aftermarket thermostat is.. Fine. It was just dumb that the OEM was swapped out thinking an aftermarket would work.
I would like to know the answer to the old question about whether it's blowing cold air or not blowing air at all.
The aftermarket thermostat is.. Fine. It was just dumb that the OEM was swapped out thinking an aftermarket would work.
I would like to know the answer to the old question about whether it's blowing cold air or not blowing air at all.
Certainly I can answer that for you. It is blowing air. Just blows very mild warm air when idling (when the temp drops on the gauge) but than will blow hotter air when I floor the gas down on the high to build RPM and make the gauge rise again)
The only time the new thermostat could be the issue is if it is opening at a lower temp than what the OEM recommendation is. They usually don't vary much but just throwing it in there.
find out were the heater core hoses come out of the firewall, feel the hoses, the temperature should be similiar in both hoses. if one hose is hot, the other is cool. blocked heater core.
This is actually one of the best comments made.
If the engine is warmed up completely (driven 15 minutes) and both hoses are hot, we know to STOP looking under the hood; the problem is inside the car in the deflectors.
One hose hot and one cooler, it is a water flow problem.
Hoses kinda luke-warm... Engine. Pressure test the cooling system - you may be surprised at what you find.
Hondas can be tough to burp. But a proper mechanic can do it with a vacuum fill kit. Your car acts like mine when it was running too cool because it had air in the system.
I just wanted to give an update to you guys, I am seeing the mechanic this week. But here goes:
So if I leave my car on idle on a cold day first start with the FAN OFF, The car will warm up to the halfway point pretty well however when I turn the fan on full with heat on, the temp drops at idle very fast. The air first comes out hot but than cools to warm pretty quickly while the temp of the engine drops.
I just wanted to give an update to you guys, I am seeing the mechanic this week. But here goes:
So if I leave my car on idle on a cold day first start with the FAN OFF, The car will warm up to the halfway point pretty well however when I turn the fan on full with heat on, the temp drops at idle very fast. The air first comes out hot but than cools to warm pretty quickly while the temp of the engine drops.
I am guessing an open thermostat. I know-even though all along we said the thermostat is new and changing it doesn't make sense.
The only time the new thermostat could be the issue is if it is opening at a lower temp than what the OEM recommendation is. They usually don't vary much but just throwing it in there.
Thermostats are made so when they fail, they fail in an open state as to prevent the engine from overheating.
Screw the reader for this.. Just look at the temp gauge.. is it in the 'normal' position? that gauge is getting the data from the ECU, which is the same thing you'd get from the reader.
Don't get me wrong.. I think it's great to have a reader.. But.. Getting one just to read the temp? Meh. The gauge won't be as accurate, but it'll be fine for this. If the sensor were out, the reader wouldn't do you any good. Well, other than a code that says the sensor is out. In which case.. MIL would be set.
Good call on the blend door. Most of them are electric now.. If the blend door isn't working properly, either due to mechanical or electrical issues.. NOW a code reader might be useful.. I don't know if it would report an issue from the HVAC module or not.. Certainly wouldn't set the MIL/SES, but a blend door issue should set a code in any vehicle from.. 2015 forward, at least. Just a matter of whether a 'basic' reader would pull that code. Just noticed this is before 2015.. So.. Questionable.
Blend door issue won't show up on a basic reader. You need one that can scan modules, if the blend door is electronic and not cable (which most modern ones aren't) then it may show as a DTC in the module. Those particular readers can be very expensive. On Fords, you can do this with Forscan which is free software.
I still think a reader would be helpful as many coolant gauges are essentially idiot lights with a wide temp range that points to the middle. The coolant gauge in my car points to 210 degrees, but the ECU is reading 190 degrees from the actual sensor. My wife's car doesn't even have a coolant gauge on the dash. Just an idiot light that shows engine temp is "cold" and goes off when proper engine temp is reached.
A reader that can pull live data is $20 or so on Amazon. Having one on hand isn't a bad idea if someone is the type that would at least like to see what an issue might be before going to the mechanic.
Certainly I can answer that for you. It is blowing air. Just blows very mild warm air when idling (when the temp drops on the gauge) but than will blow hotter air when I floor the gas down on the high to build RPM and make the gauge rise again)
That answers a lot.. Either things that weren't mentioned, or things I didn't see mentioned.
so, the gauge.. At idle. drops? That eliminates (mostly) blend door.. The cabin air filter.. You've legit got something wrong.
I'm.. a bit stuck as to what it could be, tho. Thermostat wouldn't open only at idle. Air in the system.. Again, I don't see it only at idle.
I don't think the cooling fans turning on ('stuck on high') would do this, either.
I'm a little stumped. But I wouldn't throw another thermostat at it.
If the water pump was failing.. Not pumping well at idle.. You'd see it overheating, not overcooling.
I presume you're not adding any coolant, right?
Does the gauge go all the way down to "C" or just.. Lower than normal? Or, all the way down to whatever the low range is, if it's not a "C" to "H" gauge.
It's VERY odd for a vehicle to run too cool. Usually, you're fighting to not overheat. Hondas do tend to run gauges that are.. different. Usually they don't get to the midpoint. Just calibrated so that ~200 degrees is about 1/3rd of the way up.
But.. That's my next question. What does the gauge do? Where do you always remember seeing it.. Does it get there and then drop totally out? Just drop down some?
Just read your next reply... I want to be clear, when I say fan, i'm referring to the cooling fan by the radiator. When you were talking about the fan, you're talking blower motor.
I wonder.. Do you have AC or defrost on? I know. Odd question. but.. If you were to run AC on, but the heat selector turned all the way up. You'd get hot air.. But, it'd turn on the cooling fan as well, most likely. There's just no way multiple people have missed this, tho.. Both would engage the A/C compressor.
I'm leaning two directions tho. The cooling fan or the heater core, though.. I'm not sure exactly what would be wrong with the heater core.. Just.. I'd probably grab the pipes to see if they're hot.
As crazy as this sounds.. I'd look at the A/C compressor when you turn on the heat. Does the clutch engage? It shouldn't. What if.. And I've never heard of this.. The A/C was coming on, even when you think it's off? It's a massive long shot, but.. I want to make sure you're 100% just running HEAT and this happens. Which.. If that's the case.. Is going to confuse me even more.
Last edited by Labonte18; 01-22-2024 at 01:32 PM..
Having low level of coolant can also cause the problem
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