No Heat in my S4, PLEASE HELP!

[xxBlitzkriegxx]

Hey guys, I have no heat in my car. The car is blowing cold air even when its set to high heat. I have been doing some research and flushed the heater core today to no avail. Some gunk came out, but nothing I would think could clog a heater core. Does any have any suggestions to fix this problem before winter sets in. Perhaps a handy DIY post?

(I was thinking it may be the thermostat, but that would make the car over heat if it wasn't circulating, I also considered a bad heater unit. There was antifreeze circulating through the heater core. Perhaps a hose is off) Any suggestions help!

Thanks in advance!

[Timtheguru]

Sounds like a thermostat.. if it doesn't open the coolant doesn't get hot to heat the heater core. Pretty sure that you won't know if it's overheating when the thermostat doesn't open as the coolant sensors are outside the engine coolant. I could be wrong though.

[AWDriver]

If the t- stat is stuck open then it may take a while to get heat. If its stuck shut, you would over heat but would have a warm heater. Maybe a blend door isn't working correctly. Select a cold setting and then select hot quickly listening down under the dash for sound of moving flaps.

[xxBlitzkriegxx]

If the t- stat is stuck open then it may take a while to get heat. If its stuck shut, you would over heat but would have a warm heater. Maybe a blend door isn't working correctly. Select a cold setting and then select hot quickly listening down under the dash for sound of moving flaps.

Thanks! Ill go check it right now.

[xxBlitzkriegxx]

ok, so I tuned it cold, and then hot- heard some noises, it sounded like a cd loading as i adjusted the heat and I also heard some buzzing for a few seconds. I think I also heard the shuffling of the flap.

[xxBlitzkriegxx]

Ive been told it needs to be bled, what do you guys think?

[The_Jerbel]

Does the coolant temperature get up to operating temp like usual?

[csosnowski]

i just went through this with my avant.

i flushed the heater core 3 times and each time i would get a little bit of heat for awhile and then nothing.

i ended up backflushing the entire cooling system. PILES of junk came out. looked like tiny pebbles.

refilled with new g12 and heat is so hot you could cook with it (not literally but you get the idea)

i backflushed mine with the prestone flush & fill kit by taking a piece of the heater hose i bought to flush it and cutting some off so i could plug one end of the tee that the flush thingy has.

i disconnected both heater hoses at the heater core and hooked the hose that went to the inlet (right) side of the heater core and junctioned it with one of the pieces of hose so it would drain out of the engine compartment. the other hose i hooked to the inlet (right) side and then i hooked up my other piece of heater hose that is connected to my prestone thingy and garden hose and cracked the water on. a bunch of crap came out.

i did this about 3 times and then took off the lower rad hose and drained the remaining coolant from the block.

hooked everything back up how it was and filled the system, then let the car warm up and pulled the outlet (left) heater hose (the one with the hole in it) and bled the air from the heater core. you can almost skip this step if you fill up the heater core with coolant first, but its always good to bleed it all out. the other bleeder screw is on the hose near the right side of the throttle body - its a 5mm allen iirc.

i may have missed a step or something, but this gives you a general idea of something to try!

hope this helps!

[xxBlitzkriegxx]

i just went through this with my avant.

i flushed the heater core 3 times and each time i would get a little bit of heat for awhile and then nothing.

i ended up backflushing the entire cooling system. PILES of junk came out. looked like tiny pebbles.

refilled with new g12 and heat is so hot you could cook with it (not literally but you get the idea)

i backflushed mine with the prestone flush & fill kit by taking a piece of the heater hose i bought to flush it and cutting some off so i could plug one end of the tee that the flush thingy has.

i disconnected both heater hoses at the heater core and hooked the hose that went to the inlet (right) side of the heater core and junctioned it with one of the pieces of hose so it would drain out of the engine compartment. the other hose i hooked to the inlet (right) side and then i hooked up my other piece of heater hose that is connected to my prestone thingy and garden hose and cracked the water on. a bunch of crap came out.

i did this about 3 times and then took off the lower rad hose and drained the remaining coolant from the block.

hooked everything back up how it was and filled the system, then let the car warm up and pulled the outlet (left) heater hose (the one with the hole in it) and bled the air from the heater core. you can almost skip this step if you fill up the heater core with coolant first, but its always good to bleed it all out. the other bleeder screw is on the hose near the right side of the throttle body - its a 5mm allen iirc.

i may have missed a step or something, but this gives you a general idea of something to try!

hope this helps!

Thanks! I flushed it today but i may give it another shot based on your instructions!

[xxBlitzkriegxx]

So I just discovered the car is running cooler than my past cars on the highway, about a notch to the left of the middle on the temp gauge. I also discovered the car blows heat while being held at around 2500rpm in park...but as soon as you let it idle it goes cold, more hints for a bad thermostat?

[csosnowski]

yeah, you might want to backflush the WHOLE system out, oh and i forgot to mention that i used some of that cooling system flusher and poured it directly into the heater core. then i ran the car for like a half hour or something. it says to drive like 3-5 hours and i didnt have that kind of time.

good luck!

[csosnowski]

So I just discovered the car is running cooler than my past cars on the highway, about a notch to the left of the middle on the temp gauge. I also discovered the car blows heat while being held at around 2500rpm in park...but as soon as you let it idle it goes cold, more hints for a bad thermostat?

mine did this exactly, lol. backflush ftw!

[xxBlitzkriegxx]

mine did this exactly, lol. backflush ftw!

Thanks for the advice!! The heater core outlet (closer to batt on the left) has a hole in the pipe right? You pull the hose back to expose & bleed it? I dont recall seeing a valve?

[csosnowski]

the hose actually has the hole in it. squeeze the clamp and coolant should spray out if the core's not clogged.