Heat Only on Driver Side - clogged heater core

Hot air blowing, but cold

It was about 10 yesterday in NJ at night, and I had the heat on 6 and I've noticed the coolant temperature dropping from 190 to about 170. I'm thinking it's normal since the heat is being blown into the cabin.

I've also experienced a draft of cold air either moving through the cabin, or moving from one side to another when I make a sharp turn.

Last night I've also noticed that the footwell is pretty cold even when the heat is blowing. I'm not sure if there is a lack of insulation or whatnot. I'm thinking of contacting the dealer and have the guy in the car with me, or just contacting VVoA and telling them about it..but I'm afraid I know the answer already "take it to your nearest dealer"....

tdiatlast said:

Herkguy: I've asked for that as well, but we all know the drill. Any manufacturer can get pretty tight-lipped and secretive about warranty repairs, etc., especially since they know I'm an active member of the dreaded TDIClub!!!

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Heheh... TDIclub...code for we're watching you VW

It's just frustrating because there seems to be no commonality other than the core at this point. Clogged cores are in 2012-2014, SEL, SE, low milage, high milage, warm climate cold climate.....ugh

You would really think they could just back flush the core itself and clear it out unless there is a greater issue. If there idea of flushing is flush the whole system on flow direction, then there is a reason they are not successful. You would think a core back flush and system Drain/refill would fix it.

Almir1 said:

It was about 10 yesterday in NJ at night, and I had the heat on 6 and I've noticed the coolant temperature dropping from 190 to about 170. I'm thinking it's normal since the heat is being blown into the cabin.

I've also experienced a draft of cold air either moving through the cabin, or moving from one side to another when I make a sharp turn.

Last night I've also noticed that the footwell is pretty cold even when the heat is blowing. I'm not sure if there is a lack of insulation or whatnot. I'm thinking of contacting the dealer and have the guy in the car with me, or just contacting VVoA and telling them about it..but I'm afraid I know the answer already "take it to your nearest dealer"....

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All of those things are normal... the cabin will suck out more heat than the engine can product, until the temp drops to around 160 and the electric heater kicks back on.

You'll get a "sloshing" of cold air that has settled in the floor when you go around corners. Relating to this, I've noticed that the flow of heat to the foot wells is not as much as I'd like it to be. I believe this to be due to the design of the ducting for the foot wells.

If you notice the passenger side vents producing less heat than the driver's side, then you should visit your dealer, as that seems to be one of the main telltale signs of the heater core clogging.

Disappointed with VW

Count me in as another no heat on passenger side floor. Less than 2 years old, come on VW get your act together. Does anybody know where the original heater core was made?

"Sloshing" of cold air? BWAHAHAHA!!! Sounds like you've started early on your weekend margaritas!!!

Glad you've got it all figured out. We have been wondering where the cold drafts are coming from, but never even considered air "sloshing".

That's the best way to describe it. The cold settles into the foot wells and when you go around a corner it sloshes up out of the foot wells.

It looks something like this: https://www.youtube.com/watch?v=CHl_HI_0MyI

Margaritas sound pretty good... it's happy hour somewhere, right?

VeeDubTDI said:

All of those things are normal... the cabin will suck out more heat than the engine can product, until the temp drops to around 160 and the electric heater kicks back on.

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Is this 'normal' condition when idling or are you saying this also happens while driving?

My experience during last years polar vortex event was once it reached normal operating temp (midpoint of gauge) the engine temp stayed there while blowing heat into the cabin no matter how cold it was outside, day or night, highway or local driving. It took a little longer to get to the midpoint on the gauge (maybe 7 miles versus 3 miles of driving) but it wouldn't drop off that reading once it got there.

All last winter I had no issue with the heat in the cabin or any kind of 'sloshing' of cold air in the footwells no matter how cold it got. I'd even have to back the temp off its highest setting a little because it was too warm in the car. Maybe last years experience was abnormal.

Or are you suggesting the engine temp can drop to 160 and the dash gauge won't move to reflect the lower engine temp because it isn't scaled to read that temp difference and i'd need to use vcds to see it?

By the way, i haven't heard 'polar vortex' used this year even though the severe cold temps are about the same. Did i miss the marketing memo on what we are calling winter this year?

tdiatlast said:

"Sloshing" of cold air? BWAHAHAHA!!! Sounds like you've started early on your weekend margaritas!!!

Glad you've got it all figured out. We have been wondering where the cold drafts are coming from, but never even considered air "sloshing".

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I couldn't describe it any other way. I start my days at 5am...gym...work (thankfully they're 5 minutes away from each other).

This has been going on since I bought my 13 in 2012 (late in 2012) and this is it's 3rd winter with same feeling. I just borrowed my wife's 07 Rabbit and the heat is not as strong as I thought it would be, so I think it's "normal" for VW, just like their "life fill" transmission fluid.

titleist1 said:

Is this 'normal' condition when idling or are you saying this also happens while driving?

My experience during last years polar vortex event was once it reached normal operating temp (midpoint of gauge) the engine temp stayed there while blowing heat into the cabin no matter how cold it was outside, day or night, highway or local driving. It took a little longer to get to the midpoint on the gauge (maybe 7 miles versus 3 miles of driving) but it wouldn't drop off that reading once it got there.

All last winter I had no issue with the heat in the cabin or any kind of 'sloshing' of cold air in the footwells no matter how cold it got. I'd even have to back the temp off its highest setting a little because it was too warm in the car. Maybe last years experience was abnormal.

Or are you suggesting the engine temp can drop to 160 and the dash gauge won't move to reflect the lower engine temp because it isn't scaled to read that temp difference and i'd need to use vcds to see it?

By the way, i haven't heard 'polar vortex' used this year even though the severe cold temps are about the same. Did i miss the marketing memo on what we are calling winter this year?

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Sucking the heat away from the engine is mostly only a problem when stationary. If I get off the highway and sit still for a couple of minutes with the heater on, I can watch the coolant temp go from 200 down to 170.

The cold air sloshing thing is really only a thing before the cabin warms up. It's certainly isn't a problem once everything is warmed up unless you have problems with the heating system.

If the coolant temp drops below 165, the gauge will start to move back down from the center mark. I've seen this happen a couple of times in really cold weather.

I noticed that, too... not a single mention of "polar vortex" this year even though the jet stream dip has been more pronounced than it was last year. I guess that was just a term for 2014.

touche

VeeDubTDI said:

Sucking the heat away from the engine is mostly only a problem when stationary. If I get off the highway and sit still for a couple of minutes with the heater on, I can watch the coolant temp go from 200 down to 170.
The cold air sloshing thing is really only a thing before the cabin warms up. It's certainly isn't a problem once everything is warmed up unless you have problems with the heating system.
If the coolant temp drops below 165, the gauge will start to move back down from the center mark. I've seen this happen a couple of times in really cold weather.
I noticed that, too... not a single mention of "polar vortex" this year even though the jet stream dip has been more pronounced than it was last year. I guess that was just a term for 2014.

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I use the torque app to get readouts for just about everything, and had this mounted and saw it drop down.

BTW...also a good app and tool to have for those "you need to measure the temperature of the transmission fluid" jobs.

Same deal here. Cold air on the passenger side. Original diagnosis was bad sensor. Second look said clogged heater core. THANKFULLY I came here first. Dealer said indefinite backorder on heater core and as you all know the issue is rampant. I was quoted at $680. I decidied to wait to order. If its backordered and winter is almost over then I'll be replacing a heater core in April. Also since it's an obvious issue I'll wait until they address it with a fix or a new heater core model or if it's going to keep happening over and over every 3 years get a different car.

Has there been any determination of the root cause of this problem or has anyone cut open a clogged heater core?

I'm at 20700 miles.
Not sure about the "indefinite backorder". I dropped the car at the dealership on Thursday, diagnosed late same day, heater core replaced on Friday:

561-819-031-B (factory installed was "A") heater core
561-898-380 Gasket set
G-013-A8J-1G Coolant

Techs description: "Heater core blockage part of heater core will not allow coolant to flow---tried back flushing heater core---no change in heat. "(my added emphasis)

I had to pick up the car late on Fri, tech was already gone, and the original heater core was nowhere to be seen. I had asked for a side-by-side comparison, but will have to wait for the tech to return to work on Monday.

Now I have even heat to the floor, on HI, it's hotter than I ever remember it, from day one, although we've seen very few cold days here in TX.

Just had heater core replaced on my 2012 Passat. (83k miles)
Its interesting that it seems to cost so much to flush the core that they just advise to replace it.
Not sure if its bad core or not. The dealership thought they would have a had time finding one, but they had one in2 days. 860$ later I have heat on both sides again.

After the 50k checkup on my 12 Passat TDI SE I asked the dealer to check the passenger side heat today and they capped the charge at 1h and reported the need to change the heater core, hoses and flush. This is the third this week (a Beetle and another Passat) they were following up with VOA.
Based on a search it looks like there have been plugged heater cores in the past as well a covered repair. We'll see... hard not to move forward with the repair as my commute in this atypically cold winter.

jjblbi said:

Has there been any determination of the root cause of this problem or has anyone cut open a clogged heater core?

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I'm still waiting for dogger37 to ship his old heater core to me so I can cut it open.

If anybody else has one (paying out of pocket for repair), I will gladly cut it open and report my findings. PM me for my address.

Thanks. I just tuned 48K miles in my '14 Passat and am very interested in finding out the real issue (part/chemistry/casting sand??). I'd like to proactively address this if a flush or two can lessen the chance of failure.

Heater core was replaced yesterday, it was done under warranty and i asked but wasn't allowed to keep the replaced part. He couldn't find it when I went to pick up the car, I was interested to see how small the tubing is and was going to take a picture and try to blow through it.

It was not a great overall experience. I had the car in there late january for the issue but it was backordered and i was to be called when it was available. They never called and after 4 weeks i sent an email asking about it. Service guy called the next day and said my email had 'solved a mystery' because he had no idea why a service sheet was still active on my car. He wasn't sure how long the core had been available while we drove in the Feb cold weather. Interesting they had all my contact information on the service sheet but didn't call or email to solve the mystery.

During the phone call he indicated it would be a 3 - 4 hour job. Going by that estimate, since it is a 1+ hour drive there for me I decided I would wait there while they worked on it. They have wifi so I could do a lot of office type work email work while I waited. When I got there to drop it off the same guy changed the time estimate to 6 hours. Had I been given that estimate I would have dropped it off the day before and got a ride from somebody. We decided that he would check in after about 2 hours to gauge the progress and they did end up giving me a loaner since it did look like the job would take most of the day. And it did take all day, from getting there at 8:30 it was done around 4:45.

Picked it up and they had taken the car through a car wash while they waited for me to make the 1+ hour drive to get there so the outside was cleaned up. However the inside had all kinds of dirty hand prints on the light gray door trim, window ledge, center console, etc. I used about 10 lysol wipes that happened to be in the car to get it cleaned off. The steering wheel also had the same grime on it.

Bottom line on the fix....The heat was definitely improved from all the upper vents. Not sure about the footwell vent on the passenger side though. It is warmer air bu there doesn't seem to be a lot of airflow although admittedly I don't have a good idea of what it felt like before the heat problem. With the heated seats the big issue the last month wasn't the warmth factor but the defrost issues on the windshield and side windows so that seems like it will be fixed.

Sidenote.....they also missed noting the phone call i made to them to cancel the need for the mirror control switch after someone here educated me on the ability to select one or both mirrors via the convenience menu. He mentioned they swapped the switch but it still didn't work. When I told him about selection he said they had no idea that was a feature. It's odd their troubleshooting checklist doesn't have that at the top of the chart.

Rampant incompetence. How can you not know about the features of vehicles that you service, especially when that feature has been around for over a decade.

My 13 Passat tdi spent over 2 months in the shop immediately after I bought it up for the same problem. (Supposedly no parts available) It is now doing it again and out of warranty (67k). Dealer wants 175 to diagnose and will try to get VOAA to pay for some of the repair. Im pretty sure they wont try very hard.

May try to backflush myself first.

Watching this thread!!!

Thanks for posting

Jay

I just received the clogged heater core from dogger37!

I haven't had a chance to cut it open, but initial impressions are that the core's passages are very narrow! It seems to me that the tiniest little anything (debris, sludge, whatever) will clog this thing.

Why did VW choose a core with such narrow passages? Simple: to increase heater efficiency and to extract as much heat from the coolant as possible. This makes the heater more effective (until it clogs), which is important on high efficiency diesels.

Here are some comparison pics between the Passat's heater core and a new one for a 1991 VW Jetta 1.6 Ecodiesel. Notice the very big difference in the size of the coolant passages between the two.

Great, another thread to make me paranoid. One of the reasons I parted with 2002 VW Passat GLX was because of a climatronic problem. It fluctuated between frigid air and super hot air every 5 seconds. If you got in the car and it was 90 degrees outside and you set the AC to 76, it would stay cold till it just about reached 76 and then would begin flopping back and forth from super hot to cold, to hot to cold. Set the air down to 72 and it would go 100% cold again until it got near 72 and then would fluctuate. When I got rid of the car, I had to set the temp to "as low as it would go", put fans at low and blow the air onto the floor for the best chances to not get roasted out of the car.

I purposely avoided getting an SEL as I wasn't particularly happy with my Climatronic system on my '02 and I wanted something simpler.

So, I ran out and tested my 2013 tonight which is about 20 months old and 29k miles. I had gotten home about 20 minutes prior to starting it back up and test with my temp gun. I was seeing about 125-130 out of the dash on the drivers side and 134 out of the passenger side. On the floor it was about 100 degrees on both sides. This was just at idle sitting in the driveway. Was seeing about 120 degrees on the back vents, albeit with far less air output.

So, I think I am still ok, but keeping a close eye on this one.

So I will be the one to ask the dumb questions just like in school! It's ok....I have no shame!

The one on the right is the one from the passat? Looks like the pipes are necked down to a narrow rectangular tube form on each side of the core?

Are there are skinnier tubes in the right pic behind the fins on every other row than the one on the left ? I can definitely see the tubing behind the fins on the left pic, but can't be sure I am seeing the tubing behind the fins on the right pic.

Yes, the Passat core is the one on the right.

The Mk2 core has round tubes that the coolant flows through, zig-zagging back and forth across the core (like an A/C condenser).

The Passat core has two tanks (like a radiator). The coolant passages are those thin strips that all of the fins are attached to... very skinny.

HOLY CRAP.....those thin strips between the rows of fins is where the coolant is supposed to flow?!?!?!

I thought they were support strips for the fins and the tubing was behind the fins!!

No wonder they clog up.

titleist1 said:

HOLY CRAP.....those thin strips between the rows of fins is where the coolant is supposed to flow?!?!?!

I thought they were support strips for the fins and the tubing was behind the fins!!

No wonder they clog up.

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Exactly!

So...now we need a photo or two of the NMS Passat TDI replacement heater core. Is it different?????

tdiatlast said:

So...now we need a photo or two of the NMS Passat TDI replacement heater core. Is it different?????

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I thought it was your job to get pictures!

After reading all of the posts in this thread, I figured I'd check the heat output of my Passat on the way to work (20 mile drive, 86F out). Opened the windows and turned the heat to HIGH. Let it run for at least five minutes. Thinking maybe it's possible that during the summer months when the heat is not needed that the antifreeze in the heater core is stagnant and coagulating?
VeeDubTDI, is there a physical shutoff valve to the heater core when the heat is off? Maybe we need to 'exercise' the heater every couple weeks if that is the case. I don't have the in-depth knowledge of the components to come to that conclusion.

I know that there have been issues with antifreeze mixtures such as DexCool that congeal/coagulate under certain circumstances. I'm curious if the antifreeze in our VW's is prone to blocking the passages in the heater core when not being circulated.

Thoughts?