Desperate for advice!

[Bcoble1]

I have a 2006 jetta tdi. I have posted the problem in many places and even taken it to friends whom work as actual mechanics daily and have much more knowledge than me (even though I am pretty knowledgeable on the subject).

My car has heat about 10% of the time (probably less). I have narrowed it down to the heater core just not getting as hot as it should. I figured it was clogged so I flushed it. Then it got slightly better for a night and if I kept the car above 2k rpms then it had slight heat. I figured it must be clogged and I only got a bit out. So I ordered a new one and flushed it 4-5 more times before that one arrived. It never improved beyond that. Even after replacing it I still do not have any heat. So I replaced the thermostat. still no heat. I flushed absolutely everything I could on the car thinking maybe something was clogged. I think replaced most of the coolant lines. I eventually replaced the water pump and it worked amazingly on the first start and hasn't worked since... I figured it could be something like a heater control valve but my car doesn't even come with one.

I'm $1600 into this repair and no one can figure out what it could be. I have posted in TDI forums and talked to the best mechanics I know. I even gave up and took it to two separate local shops and they cannot figure it out. Anyone here have a guess on what it could be?

 

[smokinu454]

Does the engine get up to temp?

Have you tried replacing the control panel where you adjust the heat. Some actually have a thermostat element on the back of the panel that can go bad.

Currently does It just blow cool air?

 

[Run4donut]

Does the engine get up to temp?

Have you tried replacing the control panel where you adjust the heat. Some actually have a thermostat element on the back of the panel that can go bad.

Currently does It just blow cool air?

I would look at this. It sounds like you completely overhauled your car's cooling system.

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[Bcoble1]

Does the engine get up to temp?

Have you tried replacing the control panel where you adjust the heat. Some actually have a thermostat element on the back of the panel that can go bad.

Currently does It just blow cool air?

Yes the engine gets up to temp and stays there. Confirmed by OBD2 and not just my dummy gauge.

I cannot find (on the car, internet, parts store, or anywhere else) a valve or control that would prevent hot coolant from coming into the heater core. Neither can anyone else. Those valves could definitely be influenced by the interior controls but I (and many others) cannot find any such control. If I could find a type of valve on the cooling system then I would simply delete it and see if that fixes my problem temporally. At $1600 I don't just want to waste anymore money by throwing random parts at it unless it makes sense. Replacing all the interior controls could fix some mystery valve we haven't been able to identify but it doesn't make enough sense to justify $500 in interior controls for just some random possibility. Especially when there appears to be nothing it could influence.

I know most cars have heater control valves but no one can seem to find one and VW does not even sell one for this car. It is not on any diagrams, there are no forum posts about them, and I cannot find them at any parts stores. It also would not explain why my car does sometimes get heat when I drive at 80mph in 3rd gear at 4k rpms...

 

[Jag42]

Hmmm I would think it's in your controls, knobs, etc..

 

[Bcoble1]

Hmmm I would think it's in your controls, knobs, etc..

How would the electronic interior controls prevent hot coolant from passing through my heater core piping without some type of electronic valve to stop the coolant from going into the heater core?

Also I would love to know where that mystery valve is! I would love to be proven wrong and shown where it is! lol Seriously! I have never wanted to be wrong so badly in my life! (except for maybe when I suspected my ex of cheating lol)

 

[GoWFO]

How would the electronic interior controls prevent hot coolant from passing through my heater core piping without some type of electronic valve to stop the coolant from going into the heater core?

Also I would love to know where that mystery valve is! I would love to be proven wrong and shown where it is! lol Seriously! I have never wanted to be wrong so badly in my life! (except for maybe when I suspected my ex of cheating lol)

Occam's razor, the only thing left is the controls.

 

[Bcoble1]

Occam's razor, the only thing left is the controls.

Those are the types of answers that led me to replacing the water pump... I had replaced everything in the cooling system besides the water pump and it was the 1 job I couldn't do myself. It was $700 for a new water pump installed at a local shop my buddy works at and now I still have no heat. So "its the only thing left" does not work for me.... Soon someone will say "engine swap is the only thing left" and I wont be doing that either. I don't mean to sound like an A**hole but this is not valuable input. I could very easily just start stabbing in the dark like everyone is suggesting. I am looking for real input based off of real knowledge. I understand most people here don't know much about cars but I figured I would ask since I am on this forum 12 hours a day...

 

[smokinu454]

$155

 

[Choose Life]

Its not about not knowing much about cars

Its the type of car

I made the mistake of buying an 03 Jetta

Worst car buy in my life
Ive bought driven or flipped 2 dozen

That and the Mercedes can have alot of weird stuff wrong with it that nobody knows how to fix

I would call a VW expert tech
Diagnostics will cost hundreds vs much more if you keep throwing parts at it

Buy a Japanese car
It wont break

Buy an American car
It will break
But you'll know how to fix it

 

[hellcatguy]

First please do not take any of what I am about to say as disrespectful. At best it is very difficult to diagnose something without being there, but I will do my best to point you in a direction without costing you a bunch of $. Based on your description of getting heat at a higher speed and higher rpm, you can have one of a few problems. Since you have changed a bunch of items, and flushed my gut and past experience says that the system is air bound. In many cars the heater core inlet and outlet are higher that the vehicle fill point, and or level with the fill point. There are bleeding procedures and sometimes there are bleeder ports to get all of the air out. Some bleeding procedures require multiple steps to remove all of the air. To be blunt some cooling systems are a bitch to bleed. The air could be trapped in the block or cylinder head etc. I would get a service manual for your vehicle. I did a google search and there's a bunch of backyard methods of bleeding so my suggestion is to get the service manual. Many of the posts looking for bleeding methods site a lack of heat and going through the process you have already done. Most all of them had heat after the bleed process. Also please check all of your connections and make sure there are no leaks. Any leak can re- introduce air into the system. Then you will be back at square one. If that does not pan out. There still could be a restriction. I know you say you have flushed everything multiple times, please look at all of the cooling system components. Sometimes there are oil coolers that coolant flows through. You mention that it is a tdi, so if you have an egr cooler that is restricting coolant flow that could be the culprit. You have to go section by section on each side of a component and see if you are getting the same or similar temps in and out of a flow through component. Keep in mind if there is a heat ex-changer aka a heater core there is usually some bit of difference from inlet to outlet. An infrared gun works great for this. If there is a very large difference you know where your restriction is. Please ensure that your connections that you took apart are in the correct spot. If heater hoses are hooked up backwards it will limit heat flow. Also check the blend air door. In many vehicles even in the winter, the a/c operates to dehumidify the incoming air and or the passenger compartment. If the door is in the full a/c position aka a broken door, cable , lever, if its vacuum controlled a broken or restricted vacuum line etc. you may not get heat. Other than the service manual and maybe the ifr heat gun there is very little you have to spend to do this other than your time and patience. Hopefully this should help on your endeavor. BTW a car is a car. They all break, they are all a challenge, and many times unique ways to repair. I do this day in and day out for a vehicle manufacturer on the factory side. I know it is frustrating, but be patient. Most important, take a step back breath and relax. A fresh mind will keep you on point.

 

[kyle13]

Have you tried disconnecting or touching the inlet hose to the heater core to see if it’s even getting anything? If so then it’s got to be the switch or blend door!


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[InsipidMonkey]

my gut and past experience says that the system is air bound. In many cars the heater core inlet and outlet are higher that the vehicle fill point, and or level with the fill point. There are bleeding procedures and sometimes there are bleeder ports to get all of the air out. Some bleeding procedures require multiple steps to remove all of the air. To be blunt some cooling systems are a ***** to bleed.

I agree with hellcatguy. Sounds like an air bubble is preventing coolant from flowing through the heater core.

I'm not sure what the bleed procedure is for that model TDI, but you can always start by running the engine with the controls set to full heat and the coolant reservoir open. Keep an eye out for air bubbles coming out, and keep the coolant tank topped off while it's running. Hopefully all of the air will work itself out before it gets up to temp.

Good luck, and keep us updated with your progress.

 

[rider9195]

I will third the air pocket theory. Vacuum fill is needed to properly fill the systems these days. That's the only way i will fill systems these days.

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[Freebird]

Good suggestions Guys.

I agree to bleed coolant system of air. I would then confirm heater core supply hose and return are hot when at engine temp. If you are getting hot supply to the heater core then the Blend door (the one that is controlled by the cold,warm,hot dial on the dash) more than likely as Kyle13 mentioned is not closing and directing the airflow thru the heater core as it should.

Good luck and keep us posted.

 

[WGSNewnan]

more accurately - blend door actuator may be broke. you whole system may be working properly but the door isnt allowing air to be passed over the core. that would be the very first thing I would check right now!!!!!!!
pull your glove box etc. look for actuators. turn your switches from hot to cold and from vent to defrost to floor etc. you will see the turn slowly.

Im not a VW tech so Im not that familiar with your systems per se bit I am ford and gm certified and have seen this an awful lot. too many times. for that matter I just replaced the fresh air actuator on my Ram that was exhibiting similar issues as yours.

a quick question for you - does it have heat when sitting still and warmed up? does it lose heat when you start moving at speed?

--- Post updated ---

should look something like this - about 200 each.

 

[Andrew21]

more accurately - blend door actuator may be broke. you whole system may be working properly but the door isnt allowing air to be passed over the core. that would be the very first thing I would check right now!!!!!!!
pull your glove box etc. look for actuators. turn your switches from hot to cold and from vent to defrost to floor etc. you will see the turn slowly.

Im not a VW tech so Im not that familiar with your systems per se bit I am ford and gm certified and have seen this an awful lot. too many times. for that matter I just replaced the fresh air actuator on my Ram that was exhibiting similar issues as yours.

a quick question for you - does it have heat when sitting still and warmed up? does it lose heat when you start moving at speed?

--- Post updated ---

should look something like this - about 200 each.

Wgsnewnan is right. Check the blend actuator. Look for it and see when you turn the heat on that the actuator moves. If it doesn't move the hot water won't flow into the heater core. I'm not sure where it's located but I would check it out. It's a 70 dollar part and I know you don't want to spend anymore money but look for it first to determine if it's busted.

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[CJR238]

Sounds like a bad thermostat that's not closing.

 

[Freebird]

Sounds like a bad thermostat that's not closing.

Yea, that would do it but that's one of the first things he mentioned he has changed.

 

[CJR238]

Yea, that would do it but that's one of the first things he mentioned he has changed.

I missed that.