Heating issue with the Subaru.

Shift518 Automotive
1

Let’s who is the guru around these parts and can figure out this gremlin.

The Subaru has an issue blowing hot air on occasion. It will be upto operating temperature on the gauge, blowing burning hot air as I’m moving, but then can suddenly change into luke warm air at will, whether moving or stopped.

I can turn it off, let it sit in the “off” position for a minute and turn it back on to find either hot air or still luke warm air (Most of the time goes back to hot air).

I eliminated the bubbles in the system as being an issue by having a coolant flush done at Fire Stone.

They told me, that the radiator cap was not holding pressure so I replaced that as well.

Still happens.

So from what I understand its
Low coolant
Thermostat
Heater Core
Radiator Cap
Leaking hoses

are out of the equation. I’m stumped.

2

Loose nut behind the wheel?

3

Aren’t you Russians supposed to be used to the cold? Why do you need heat? :tong :hug

4

take it back to firestone. they fucked up. have them deal with it for FREE.

5

Firestone FTL. My Zed24 did the same thing when the system wasn’t burped properly.

6

could be a resistor car, faulty control head, if you can see/feel the header core make sure it’s getting warm… if it is then you know it’s gotta be electrical, you could also feel the hoses going in and out of the firewall to make sure the lines are heating up

7

I’d help but my love for Subaru is non-existant. Freaking junk. :headbang

8

Most firestone mechanics are as dumb as rocks, i’ll bet there is air in the system. Don’t get to over complicated, start with the basic stuff first.

9

try checking the mode door/blend door actuators in the dash. they divert hot and cold air to regulate temperature. one could be broken in the dash and is getting blown open/closed by the blower motor. but what do i know… :umm

10

sounds like the heater core is clogged up… you might need to let some draino sit in there and blow it out wit a pressure washer back and fourth to unclog it.

11

thats actually not very common with subaru’s… my money is still on the mode/blend door.

12

sounds like either/or but i believe ya that happend to my buddys ac so we just tied it shut.

13

Thats wierd, I always thought subaru’s got really hot. Almost to the point of bursting into flames.

14

ill put money on the core is pluggin up doesent matter if its common or not it happens we have a core flushin tool at work works wit the hose and air blasts most shit out never seen it not work :nod

15

If my core was clogging up wouldn’t it be always blowing mediocre air?

If I come back there without any solid proof of the air in the line how would they be liable to redo the service?

Heater core would be the worst case scenario. In Japanese cars that’s pretty much the first item that goes into the shell and everything builds around it… not fun.

16

vlad, like i said… mode door/blend door actuators in the dash… get it looked at.

17

if a core starts cloggin it will push heat in the higher r,s due to more water pressure bein fed into them ,the best way to tell is get the car to runnin temp see if heater core hoses are equal pressure or very close to the same any diff in like 15 degrees ya know its there.and air wont be trapped in it if filled correctly

18

if it was a door it would be constant not on and off

19

not necessarily. if the door itself was broken off the actuator it could be being blown side to side by the air itself. thus creating the hot/cold effect.

20

not likely as there is pressure on it in either direction it wouldnt be all floppy like a cock