Please help me...

[jdenicola187]

My heat isn't working in my s4
i also have a cel for coolant temp sensor
if i fix the cls you think my heat will work again
i dont think its the heater core cause i can't smell antifreeze

[JDM EJ1 95]

does the engine heat up?


fix your temp sensor.. and see if its running at proper temps..

then go from there.

if its not warming up.. then it probably needs a thermostat

[gointoscott]

Yeah coolant temp sensor's are known to go bad on our cars. Real easy to replace. There is writeup on audiworld.com I had to replace mine just because it was throwing the code (the gauge worked fine but kept getting the CEL light) I didnt have a problem with my heat before I put a new temp sensor in either.

About your problem with it not heating, I agree that it sounds like a thermostat problem. Or sometimes if its low on antifreeze it wont heat??? I'm guessing you would of checked that already. I'd def wait to drive it till you get the temp sensor fixed because some times if there is a thermostat problem the engine will overheat and that can ruin the engine.

It could be an easy fix, but could get expensive too - especially if you have to replace thermostat - better to just do a timing belt, waterpump and thermostat replacement since you have to tear front of engine apart to get to thermostat.

Hope the best for you.

[jdenicola187]

hope its not the t stat

[JDM EJ1 95]

hope its not the t stat

why?

its an easy fix

[gointoscott]

why?

its an easy fix

I had posted that replacing the thermostat required tearing front of engine apart. What I meant was I thought you had to pull the radiator support forward to have enough room to get to the waterpump/thermostat area.

So there would be considerable amount of work getting to thermostat. I havnt replaced it personally so maybe I am not correct. I dont mean to give wrong information.


Are the thermostat's easier to get to in our S4's?

[jdenicola187]

i dont think its the t stat cause the car is still reading temp inside on the gauge

[gointoscott]

Could you give us more info of what the problem is?

Like you say the temp gauge is working, Where does the needle go to when car is warmed up? Usually the needle is right in the middle of gauge.

You say its not heating? Is it blowing any air at all? If its not blowing any air then the problem is related to the blower motor, or inside controls.

[jdenicola187]

the car does blow air, the gauge goes right to the middle for temp

[Jung]

ambient air temperature sensor? just a thought. if it's reading too high of a temperature it won't turn on the heat, right?

[AudiTechS4]

your blend air door motor might be toast

[gmann]

your blend air door motor might be toast

What I was thinking. Turn the temp down to "lo" and see if it will blow A/C.

And SHAME on whomever said something about doing the water pump, timing belt service instead of doing a t-stat. Have you ever done a t-stat? It's not that hard... It's a hell of a lot easier than doing a damn timing belt service

[GetAwayFromMe]

Take the battery cover off and check the heater hoses. If both of them are hot than you have an inside problem i.e. blend door motor, heather control unit, ambient sensor etc. If only one of them is hot than your heather core is plugged. If both of them are cold than you have engine coolant problem. Thermostat, water pump, something plugged etc.

You just got to get in there and go through everything til you find your problem.

[gointoscott]

And SHAME on whomever said something about doing the water pump, timing belt service instead of doing a t-stat. Have you ever done a t-stat? It's not that hard... It's a hell of a lot easier than doing a damn timing belt service

Yes that was me. Again I apologize for giving the wrong info. I thought the thermostat was hard to get to down by the water pump, so that is my bad. Now I know.

There are some good suggestions of how to troubleshoot your problem. Let us know when you find the problem.

[jdenicola187]

i just check the hoses going into the heater core and they are both hot,
in the summer the a/c worked fine but i never check the heat until it started getting cold here

[s42k5b]

i thought the t sat was behind the timing belt? am i wrong?

[s42k5b]

I'm having the same problem in my car. The heat works when you first turn it on then it gets colder and colder. If im on the highway cruising, my water temp will drop down to the second mark on the cold side. I'm going to try and replace the coolant temp switch and hopefully that will fix my issue

[GetAwayFromMe]

i just check the hoses going into the heater core and they are both hot,
in the summer the a/c worked fine but i never check the heat until it started getting cold here

That means your t-stat is working. Dig in there and get to the blend door motor and see if it moves when you switch from cold to hot and get a test light to see if it's getting power. The blend door motor will get power just for a second as you are pushing the botton for hot. So find a ground for the test light put the needle on positive and as you pust the botton to cold or hot the light will blink. If it doesnt than you are not getting power, your next step is to test the heather control unit. Try cleaning the ambient temp sensor and see what happens.

To find a problem like this you just have to go step by step and pin point things til you find what's not working right.

[GetAwayFromMe]

i thought the t sat was behind the timing belt? am i wrong?

You are right

[jdenicola187]

how do i get to the blend doormotor

[GetAwayFromMe]

Remove complete front section of center console. Loosen floor outlet from the right instrument panel support than you should see some connectors. While you are moving the temp from low to hi look at the motor to see if it's mooving, if not than test it like i stated above.

[jdenicola187]

i just checked the blend and the motor works i can see the lever moving too

[gointoscott]

What does your outside temperature read in the dash?

Is it fairly accurate? If your outside temp sensors or inside temp sensors are not working right, it will tell the computer the wrong info and the heat wont kick in.

[jdenicola187]

yes the outside temp is fairly accurate

[GetAwayFromMe]

Got anyone close to you with an A4 or S4 so you can swap heather controls and see if that could be the problem.

[jdenicola187]

i gotta get a new one cause my buttons are sticky, but how the hell do you get it out

[gointoscott]

Did you replace your coolant temp sensor yet?

[gmann]

Did you replace your coolant temp sensor yet?

just because it's a CEL doesn't mean that the sensor is busted.... You should check them before you get new.

[gointoscott]

He stated in the first post he had CEL for coolant temp sensor, so I assumed he had that checked already and knew it was bad.

After all it is a common problem our cars have.

That is why I asked if he replaced it yet.

[jdenicola187]

no i have not im waiting for the sensor to get here

[gmann]

He stated in the first post he had CEL for coolant temp sensor, so I assumed he had that checked already and knew it was bad.

After all it is a common problem our cars have.

That is why I asked if he replaced it yet.

changes are you're right. But I've ran into corrosion inside the connector and it was fine. Not saying it will be corrosion on yours. But it could happen.

[jdenicola187]

ok so i just put in a new coolant temp sensor and the car is still not blowing hot air, i need to get this fixed asap

[MissingPixels]

A quick FYI guys - Most cars have two different sensors. There is a coolant temperature sensor for your ECU in your water neck/thermostat housing. There is also a temperature "sender" in the water neck or thermostat housing which is for your dash gauge. Some cars also have an additional sensor in your radiator for controlling your fan.

Your water neck and thermostat hosuing are not next to your water pump. Either way, replacing a thermostat or a sensor isn't a hard job.

[s42k5b]

A quick FYI guys - Most cars have two different sensors. There is a coolant temperature sensor for your ECU in your water neck/thermostat housing. There is also a temperature "sender" in the water neck or thermostat housing which is for your dash gauge. Some cars also have an additional sensor in your radiator for controlling your fan.

Your water neck and thermostat hosuing are not next to your water pump. Either way, replacing a thermostat or a sensor isn't a hard job.

its behind the timing belt..alot of shit has to come off

[s42k5b]

Your T Stat is most likely stuck in the open position. Time for a new one.

[gointoscott]

Your T Stat is most likely stuck in the open position. Time for a new one.

Ok I agree that the thermostat isnt as easy to replace as some say it is since its behind the timing belt cover. I have never personally replaced one on our S4's but I think you have to pull the radiator support forward and put it in the open position. Not that hard to do, but still a job.

With that said I thought earlier someone said that if both heater core hoses were hot that it means the thermostat was working fine. Plus he said that his temp gauge goes to the middle when its hot so that is more evidence pointing to the thermostat working right.

To me it must be an iside problem. I read that it Could be the controller, or a vacuum leak, or a stuck valve, or a stuck deflector flap.

He did mention that his buttons are sticky maybe its in the controler.

[s42k5b]

Ok I agree that the thermostat isnt as easy to replace as some say it is since its behind the timing belt cover. I have never personally replaced one on our S4's but I think you have to pull the radiator support forward and put it in the open position. Not that hard to do, but still a job.

With that said I thought earlier someone said that if both heater core hoses were hot that it means the thermostat was working fine. Plus he said that his temp gauge goes to the middle when its hot so that is more evidence pointing to the thermostat working right.

To me it must be an iside problem. I read that it Could be the controller, or a vacuum leak, or a stuck valve, or a stuck deflector flap.

He did mention that his buttons are sticky maybe its in the controler.

yeah i hear you man....my temps were coompletely normal too when my heat wasnt working. I just had the tsat replaced and it fixed my heating issue.

[jdenicola187]

i did get a new hvac unit and it looks almost new, no more sticky buttons but the t stat was already replaced

[jdenicola187]

im leaning toward it being something inside? has anything been known to go bad internally with these cars?

[gmann]

im leaning toward it being something inside? has anything been known to go bad internally with these cars?

Internally as in the cooling system? The only thing that's "internal" in the cooling system is the t-stat.... And the coolant.... And it sounds like your t-stat, still.

I'd take it to a shop and let them figure it out and fix it if you're that worried about it, which you sound that you are.