Another heater core?

IndigoBlueWagon

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Aug 16, 2004
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South of Boston
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'97 Passat, '99.5 Golf, '02 Jetta Wagon, '15 GSW
There's nothing wrong with those temps. I have an EGT gauge in my ALH and 122-1300 degrees when climbing a long hill at 80 MPH isn't uncommon. It helps keep the turbo free of carbon. It's worse for these engines to constantly baby them.
 

x1800MODMY360x

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Jun 27, 2021
Location
AZ, USA
TDI
2013 Passat TDI SEL
There's nothing wrong with those temps. I have an EGT gauge in my ALH and 122-1300 degrees when climbing a long hill at 80 MPH isn't uncommon. It helps keep the turbo free of carbon. It's worse for these engines to constantly baby them.
Sorry I guess being half asleep didn't help finishing my post. I meant to say being in those high temps in Regen then people just turn off the car with out the turbo to cool off from those high temps or to allow Regen to complete.

Before I got a gauge I didn't know when Regen was happening.
 

740GLE

Top Post Dawg
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Aug 19, 2009
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NH
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2015 Passat SEL, 2017 Alltrack SE; BB 2010 Sedan Man; 2012 Passat,
the ecu takes care of any excess heat, coolant pumps and fans run to cool it down. It's not 1970.

Be mindful even if you park the car it'll still try and finish the regen, so you may have to wait, so you might find youself driving around for another 10-15 min if you want.

Also I've also seen the ECU keep rpms at elevated levels at idle well past the regen is complete (20-25 min of idling), had to blip the throttle to bring rpms back to 850.
 

Navajobeng

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Dec 14, 2021
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Wisconsin
TDI
2013 passat sel
So I’ve read as much as I could about frequent heater core replacements. I have 2013 passat tdi sel. Bought it with 70k. I had the dealer replace the heater core the first winter at 80k under warranty. Then agian the next fall at 90k. Then again this fall at 110k. But this time it failed 2 weeks later. They took it back and they flushed both directions and pressure flushed the system at least 10 times they said. They also replaced the heater core again. All under warranty. I picked it up drove about 5 miles. The air on passenger side floor was Luke warm at best. But hot coming out of the upper vent. I drove right back to vw to tell them and leave the car there. They said “just drive it a bit, it needs to circulate.” I drove it 4 hours today with ice cold air out of all passenger vents after the first 30 minutes. And a whining noise ( my freezing wife) the whole way. Called them immediately and they said I must have other components coming apart throughout the system. The radiator, oil cooler, transmission cooler. That vw would not let them replace the heater core after 3 times without flushing and checking flow each of the other components. That they would diagnose for free. but the only part under warranty is the heater core. I have to pay for the other parts and labor. Possibly as low as “$1,600 up to $4,500”. well this is not going to happen. Because once it’s apart. I’m screwed into paying or towing it away. I mentioned what I read about the egr cooking the coolant. They blew that off as I don’t know as much as they do. They said they have the same issues on gas Cars as well. Maybe so but I doubt it’s yearly heater cores. I was going to just replace all the components myself (except the heater core) for about $500 then take it back and let them do their thing. But it likely will fail agian anyway. So what’s the point! Sorry the post is so long. Any advice would be appreciated.
 

oilhammer

Certified Volkswagen Nut & Vendor
Joined
Dec 11, 2001
Location
outside St Louis, MO
TDI
There are just too many to list....
Mixed/contaminated coolant can clog up cores on the gassers, too. I just flushed one on a 2015 2.slo Jetta that had been previously messed up by morons. So yeah, it can happen on those.

I have been reasonably successful with flushing them the opposite direction of flow with a garden hose after soaking them with Permatex Heavy Duty radiator cleaner.


That stuff is powerful, and it works. I *JUST* put it in the heater core/pipes, and not anywhere else. Yes, I know it says not safe for aluminum, and yes I know the pipes and core are made out of aluminum. I don't leave it in there for very long, and if it messed something up (never has, but if) you'd be back to replacing it anyway, so what is the harm in trying?

Here is how I do it:

Disconnect both quick couplers at the heater core pipes on the firewall, and move them out of the way and secure them so nothing else gets in them.

Get two lengths of bulk hose, about a foot or so long, 3/4"/19mm ID, and slip them on to each pipe, and angle them UP.

Pour the cleaner down both hoses until they are both full. If the core is not completely clogged shut, which they usually are not, just pouring it in one hose is enough, as liquid seeks its own level and it will come back up the other. Try not to spill any. One quart bottle is enough to do it a couple times at least.

Let it soak for about 20 minutes. You may see some bubbles and foam come up as it dissolves the solids inside. Pull the hose off from the TOP pipe connection, leave the lower one in place.

Rig up a garden hose to fit in the hose that is still attached to the BOTTOM pipe, then turn it on full while watching what comes out of that top connection. You'll see a black/brown slurry of filth come pouring out... keep the hose running until it comes out clean and clear.

Turn the water off, remove the hose, reconnect the quick couplers, refill the system with G12 mix, put anything back together you had to remove to get at the firewall, take the car for a drive and make sure the system is full.
 

mrrhtuner

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Joined
Mar 29, 2011
Location
London Ont Canada
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2003 Jetta Wagon TDI, 2015 Passat TDI, 2015 Touareg TDI
My 2015 passat came with g12 now 61000 miles, no trouble. build date was may 2015. Does anyone know if they installed different heater cores in later production cars and when they started using g13 in the passat. My golf, built same month, is a g13 car. Any test data as to thermal chemical breakdown comparing g12++ vs g13?
There may be something about g13. My passat was built in may 2015 and came with g12. No hint of problem at 65k. My golf was built also in may but came with g13. I've topped off both with g12++. It may be the egr cooler breaks down g13 quicker than g12. g13 supposedly is "greener"----thanks alot.


How do both of you know for fact that your car came with G12?
 

adjat84th

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Joined
Dec 13, 2008
Location
Virginia Beach, VA
TDI
'01 Jetta TDI/'15 Golf TDI
Is there a sticky that lists everything that needs to be done for the fix it and be done with it. My 2012 passat has the dreaded heater core plug and just as soon fix this issue and be done with it.
Delete the item that is boiling the coolant just before it enters the heater core.
Not sure of an EGR-only delete on the CKRA, but for the EA288 (CVCA/CRUA) this kit would allow the DPF to stay in place. Would need a tune though.
 

93celicaconv

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Wisconsin
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Turned in my 2010 Jetta TDI Cup Edition to VW, DSG, Nav, Sunroof / Replaced with a 2015 Passat TDI SEL Premium
Perhaps reviving an old thread, but I was told today when looking for some G13 concentrate antifreeze for my MY2015 Passat TDI that dealerships no longer carry G13 in any form, but instead have G12 EVO. The parts counter person I talked to said the G13 was discontinued due to DPF regen heat problems resulting in heater core plugging. The G12 EVO is supposed to be a new product from VW aimed at eliminating this issue. Anyone have any knowledge/experience with TDI's and the new G12 EVO coolant - anyone have clogged heater cores after making such a switch?

I have 107k miles on my MY2015 Passat TDI, never had a heater core problem - yet. I've been monitoring pH routinely and have likely flushed the cooling system 3 times in it's life so far. I can still get some NOS G13 concentrate for future coolant flushes, but if G12 EVO eliminates the heater core plugging issue, maybe G12 EVO is a better coolant to go to for the system time the cooling system is flushed? I usually do my own coolant flushes.
 

pedroYUL

Top Post Dawg
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Sep 8, 2011
Location
MI, USA
TDI
2015 Passat CVCA; 2015 GSW CRUA; 2012 wagon CJAA; 2004 wagon BEW(brother)
I visited my local dealer just last week to get G13 and they only had the 1L concentrate.

Their story is completely different than what your dealer told you @93celicaconv . They said VW corporate only lets them sell G13 for 2015 TDIs, not any other years, and that they have to record by VIN and report back to corporate in order to get more G13. All other cars and years, including Audi are onto G12 evo.

They also told me that G13 has been a complete and utter mess, for some time they were opening new containers and adding some stuff that was "missed" by production!
 

IndigoBlueWagon

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'97 Passat, '99.5 Golf, '02 Jetta Wagon, '15 GSW
It's correct that 2015 2.0L TDIs are supposed to continue to use G13, not G12 Evo.
 

93celicaconv

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Turned in my 2010 Jetta TDI Cup Edition to VW, DSG, Nav, Sunroof / Replaced with a 2015 Passat TDI SEL Premium
So why is VW allowing G13 for MY 2015 TDI's, but no others? That seems rather strange to me. Is that the safest way to get rid of their surplus inventory, as it won't potentially affect as many heater cores as others? Yes this thread has more than I expected MY 2015 TDI's that had to have heater cores replaced. I don't get it.
 

IndigoBlueWagon

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'97 Passat, '99.5 Golf, '02 Jetta Wagon, '15 GSW
I don't think they're trying to get rid of surplus inventory, since dealers no longer stock G13.

I'm not sure why VW spec's G13 for CRUA/CVCA engines. But bear in mind that the person who told you that the move to G12 Evo was to address heater core failures is the same person who didn't know what coolant was correct for your car. Probably not the best info source.
 

93celicaconv

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Turned in my 2010 Jetta TDI Cup Edition to VW, DSG, Nav, Sunroof / Replaced with a 2015 Passat TDI SEL Premium
But G13 was used for all VW/Audi vehicles at some point, not just MY2015 VW Passat's. At least that is what I understand. And this thread talked about how poorly G13 handles the increased regen heat generated, especially on the MY2012-2014 TDI engines. What I'm not clear about is why, of all the cars VW produced that had factory filled G13 in them, why now is G13 being reserved only for MY2015 TDI's (which is what you said). I can understand a dealership having no G13 in inventory saying the new coolant for a 2015 VW Passat is G12 EVO. But I don't understand the logic of what your VW dealer said regarding exclusivity of the G13 still in dealership hands to only be used on MY2015 TDI's. Or maybe I misunderstood something.
 

AverageAndy

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2013 Passat TDI SEL, 2013 Golf TDI 6MT, 2013 Jetta TDI 6MT (R.I.P.)
My coolant reservoir says G12++ and I am pretty sure that is what was in it originally. Very sure that is what is there now since I replaced it with Zerex G40 when I did the timing belt.
 

93celicaconv

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Turned in my 2010 Jetta TDI Cup Edition to VW, DSG, Nav, Sunroof / Replaced with a 2015 Passat TDI SEL Premium
I'm not sure how to copy a PDF file to this forum. But I have a Technical Service Bulletin (19 20 04 2025303/11) dated June 25, 2020. It's for Audi vehicles. On it, is says:
  • G13 has been introduced in MY 2008 as initial fill and service coolant.
So maybe VW didn't use it that early, but Audi did? Audi had cars with the same TDI engines VW had in their cars, using the same DPF's & regen systems. But perhaps not the same coolants?

The same Technical Service Bulletin says:
  • G12evo was introduced in MY 2019 as initial fill and service coolant.
It also says G12evo can be added to vehicles already containing G11, G12, G12+, G12++, and G13 without any issues or reduction in service life.

So here is my main question: For my next coolant flush & refill (planned for 2024) in my MY 2015 Passat TDI, should I try to find remaining stock of G13 or should I instead start using G12evo? Or doesn't it matter?
 

BKmetz

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2015 Passat, titanium beige, 6MT
Use the G12evo and don't look back.

I'm glad to hear VW finally realized the glycerin based glycol (the magic sauce of G13) was cooking the glycerin out of the coolant under regens and plugging up the heater cores. If G12evo isn't available, use G12++. There is no magic in all these HOAT coolants so don't get hung up on G12evo or G12/G12++, just stay away from G13. Let the dealerships use G13 in the gasoline powered cars where it won't do any harm.

Good luck.
 

93celicaconv

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Turned in my 2010 Jetta TDI Cup Edition to VW, DSG, Nav, Sunroof / Replaced with a 2015 Passat TDI SEL Premium
Looks like G13 uses glycerin, as BKmetz stated. G12evo uses the original ethylene glycol. I'm leaning towards the next coolant flush to go with the G12evo, based upon what I am sensing.

The VW dealer by me only has G12evo in 1 gallon containers as a 50:50 premix product. They do have the concentrate (which I prefer, since I flush with distilled water and can't get the system emptied 100% after my final flush process (which is almost 100% distilled water at that time)), but it is only available in the small 1 liter bottles, for $39 per liter at my dealer. I see that the G12evo concentrate 1 liter bottles run $16.19 at ESC Tuning though, so that cost isn't as terrible as the dealership cost. Looks like the coolant capacity of a MY 2015 Passat TDI is 8.0 L (interesting that the 2012-2014 Passat TDI's have a cooling system capacity of 10.6 L), so would need 4.0 L for the flush process, plus 1 or 2 bottles of concentrate on the shelf as spares (or the 1 gallon of 50:50 premix for topping off).
 

jjblbi

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lbi, nj
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2014 Passat SEL TDI
Is there a consensus on an aftermarket coolant for a 2014 CKRA? I prefer to flush with distilled water and last time I bought VW it seems they only have premix. Thanks, John
 

r11

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Mar 6, 2012
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NJ
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2012 Passat TDI SE 6MT (BB'd), 2015 Passat TDI SE 6MT
My core is plugged, lukewarm air at best. I stupidly requested coolant flush first, hoping it would fix the core. It didnt.
Some folx say there heater cores got replaced under the 11/162K extended wty ? After all, it does seem that cooking the coolant during regens is is what produces sediment and VW now is aware of that ?
Will head to dealer in a few, see if I can get them to agree to do it under wty. Any TSB to aware off ?
 

L30NDR3Z

Member
Joined
Feb 24, 2021
Location
Illinois
TDI
Passat TDI SE NMS 2014
My core is plugged, lukewarm air at best. I stupidly requested coolant flush first, hoping it would fix the core. It didnt.
Some folx say there heater cores got replaced under the 11/162K extended wty ? After all, it does seem that cooking the coolant during regens is is what produces sediment and VW now is aware of that ?
Will head to dealer in a few, see if I can get them to agree to do it under wty. Any TSB to aware off ?
I had my heater core replaced three times and then multiple engine component to fix the problem I’ll have to find the paper work but there is a TSB for the heater core if you have the 2.0L TDI (CKRA) (2013-2014) engine
Look up (80-16-01 - No Heat from Passenger Side Cabin - Heater Core
Restricted (CKRA Diesel only)
 

Penst8grad

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Nov 24, 2017
Location
Pa
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2015 Passat TDI SEL
Just had the 2nd heatercore done in 8 months/14k miles by the dealer. 45mpg is nice but when my wife has no heat, not so nice. If momma isn't happy nobody is happy.

Thinking the 15 Passat's time with us is coming to a close soon and without TDI there really is nothing drawing me to another VW product.
Currently putting in 5th one. It's become an annual event. Going to be fixed permanently this time.
 
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x1800MODMY360x

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AZ, USA
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2013 Passat TDI SEL
Currently putting in 5th one. It's become an annual even. Going to be fixed permanently this time.
Mine went out as I had the engine out, coolant lines got crusty and clogged the core.

Not a big priority right now as I'm the sole rider in my passat, and want to clean the coolant system before replacing.
 

93celicaconv

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Turned in my 2010 Jetta TDI Cup Edition to VW, DSG, Nav, Sunroof / Replaced with a 2015 Passat TDI SEL Premium
Currently putting in 5th one. It's become an annual even. Going to be fixed permanently this time.
You have a 2015 Passat TDI? And have your 5th heater core replacement in it (6 heater cores including the original) in it since new? I don't understand. I have 123,000 miles on my 2015 Passat now, live in Wisconsin (we need the heat now), and it is working fine. What could possibly be different between our two cars?
 

93celicaconv

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Turned in my 2010 Jetta TDI Cup Edition to VW, DSG, Nav, Sunroof / Replaced with a 2015 Passat TDI SEL Premium
Mine went out as I had the engine out, coolant lines got crusty and clogged the core.

Not a big priority right now as I'm the sole rider in my passat, and want to clean the coolant system before replacing.
What model year Passat TDI do you have?
 

Penst8grad

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Pa
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2015 Passat TDI SEL
You have a 2015 Passat TDI? And have your 5th heater core replacement in it (6 heater cores including the original) in it since new? I don't understand. I have 123,000 miles on my 2015 Passat now, live in Wisconsin (we need the heat now), and it is working fine. What could possibly be different between our two cars?
No idea the 1st 2 by the dealer and another 2 by independent shops. I can only assume that it is related to G13. Maybe yours does not have that? Called VW customer care and got no help whatsoever because it is a '15.
 

93celicaconv

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Turned in my 2010 Jetta TDI Cup Edition to VW, DSG, Nav, Sunroof / Replaced with a 2015 Passat TDI SEL Premium
No idea the 1st 2 by the dealer and another 2 by independent shops. I can only assume that it is related to G13. Maybe yours does not have that? Called VW customer care and got no help whatsoever because it is a '15.
All my coolant changes have been with G13. Next one will be G12 EVO. I take pH samples periodically on the coolant, and change it if it gets down to 7.5 or lower. So I don't think the issue is due to having G13 as the coolant. No coolant should be left to go acidic, which it gradually degrades to over time.
 
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