Coolant turning brown

[Pel1431]

Hey guys I have a 2014 Volkswagen Passat TDI The antifreeze coolant was pink color before this happen. The car started to overheat due to the heater core being stuck, I turn off the car and check the coolant and the coolant was brown and had a plastic burning smell to it. The dealer flushed it twice and replaced the heater core but the coolant is not as pink as before. What do you guys think that can cause the coolant to smell like burnt plastic and makes color dark brown? I checked the oil and everything looks OK. Please help Thank you

 

[eugene89us]

Refer to my thread here, lots of great, smart individuals provided plenty of evidence for coolant degradation. Your best bet is to make coolant exchange your yearly maintenance job. I have not yet found anyone that experimented with alternate coolant, preferably without silicates, which the belief that it, along with glycerin in G13 coolant, cause this rapid degradation. One day, I will pull the trigger and switch Passat to match older technology BMW blue coolant. But I am not there yet. Here is the thread you may find useful:

Leaking Oil Cooler Housing and an Interesting Find Inside

Good morning, everyone! Just like many of you here with higher mileage Passats, the leaky oil cooler struck me too. I had coolant leak at approximately 1 gallon every 100 miles, since as if on purpose the leak started when the car was very far from home. To make long story short, noticed the...

forums.tdiclub.com

 

[Tom in PT]

^ good advice, except I am unsure about the BMW blue coolant. I am going to do a flush and replace with G12 or G12+++, both of which are Pink, like my original fluid. My '12 says G12 right on the reservoir.

 

[x1800MODMY360x]

^ good advice, except I am unsure about the BMW blue coolant. I am going to do a flush and replace with G12 or G12+++, both of which are Pink, like my original fluid. My '12 says G12 right on the reservoir.

When I bought my car from a small TDI dealer, he said that the G13 was crap and never use it. My car have and still use the G12. Still no issue with any system involving coolant.

 

[Zambee500]

So just for clarification for the ignorant (i.e., me), the G13 and G12++ (2 pluses) are glycerine based HOAT coolants and "bad" for application in CKRA dieselgate engines?

For CKRA engines, we want G12 or G12+ (1 plus) which are OAT and do not have glycerine. Correct?

I thought G12 was discontinued and about impossible to find. The trusted vendors here seem to only have G13 or G12++ and that is only option, which if i understand correctly is not really a good option for CKRA.

I did see on RockAuto that they have a Pentosin product ("SF G-12+" with product # 8114107) and a Beck/Arnley product ("Euro SF+" with product # 252-1021) that indicate with their product name that they are G12/12+ equivalent (1 plus) and at least Rock Auto clearly indicates whether the after-market ones are OAT or HOAT.

The Valvoline/Zerex G40 is confusing because it is pink and they claim compatible, but it is HOAT and says on back label that it is 12++ compatible, which means "bad" (for application in our cars anyway).

All so needlessly confusing.....

 

[eugene89us]

My understanding is that the only glycerin-containing coolant is G13. All G12 varieties are glycerin-free. The Zerex G40 that I started to use is G12++ equivalent - it is ethylene glycol based (without glycerin), but it is Si-OAT technology with silicates. Going from G13 to Zerex G40 removes the unnecessary glycerin component which may precipitate into sludge. Since others have hypothesized that silicates may create those flakes that clog the heater core, it may be worth trying your luck with G12 or G12+, since those appear to be silicate-free OAT coolants. But I am taking 1 step at a time. If I find Zerex G40 to degrade also, I will then research into less plusses to eliminate silicates from the coolant.

 

[Zambee500]

Thanks. The Zerex G40 doesn't mention glycerin anywhere on the label that I can see, so perhaps that is indeed a good option. The FCP Euro website listed "Ethylene glycol/glycerine based" for every G12++ that I saw there, so I thought it was glycerine based. But that could be an error on their website, or particular products, and I couldn't read the labels in the photos clearly at all.

I'm gonna try flushing with G12/G12+ at next scheduled maintenance, if I can land a few liters of the Pentosin concentrated version.

Speaking of, I wonder how coolant concentration also affects this issue. Stick with 50/50, or perhaps 60/40 or even 70/30? Or would increasing concentration make things even worse?

 

[Tom in PT]

I would stick to 50 50 or perhaps even reduce the concentration of the antifreeze below 50 percent to maybe 40 percent if I lived in a warm climate. No way would I put in more than 50 percent antifreeze, especially a G13.

Pentosin Pentofrost SF is what I am going to use, G12.

Pentofrost SF Antifreeze (1.5 Liters) - Pentosin G012A8G1G

Pentofrost SF Antifreeze (1.5 Liters) - Pentosin G012A8G1G

www.fcpeuro.com

 

[Nuje]

There's a technical bulletin to the effect that the new "official" VW coolant (can't remember the number) could be mixed with the G13 coolant, but the coolant could/would turn brown, and that this was normal, and not at all a problem.

For me / my car, though....just no way I would abide brown-ish coolant; that would get addressed very quickly.

 

[eugene89us]

@Nuje I think you may be talking about new G12 Evo coolant. I believe it was approved for many Audi models and it can turn other coolants brown when mixed. However, if I recall correctly, it contains glycerin also for nature friendliness. On the other hand, VW says the purpose of its redesign was due to engines operating under harsher conditions/tunes in order to meet emissions requirements. Whether it turns out most stable than current coolant remains to be seen. However, I think for cars our age, going older tech to Silicate-free OAT may be the best thing. I believe silicates actually are supposed to attach/line the aluminum parts of the engine to prevent pitting of the cylinder head and corrosion. However, over time, these silicates can turn into fine powder and cause mayhem. So you pick corrosion over clogging/degradation, or as I suggested earlier, stick to G12++ to maximize corrosion resistance, get Schwaben vacuum fill tool and simply replace your coolant annually with each oil change. It is a cheap insurance.

 

[eugene89us]

@Tom in PT Please let us know how G12+ operates and if there is any degradation or corrosion that you may see. You end up downgrading to reduced corrosion resistance. But completely clogging heater cores and oil coolers is an unacceptable alternative too. I am starting to see some particulates in the expansion tank for current G12++ (Zerex G40), so I think I will drain and maybe try G12+ next. I need to keep the new oil cooler from clogging as I showed in my oil cooler post. It is ridiculous!

 

[Zambee500]

Pentosin Pentofrost SF is what I am going to use, G12.

Pentofrost SF Antifreeze (1.5 Liters) - Pentosin G012A8G1G

Pentofrost SF Antifreeze (1.5 Liters) - Pentosin G012A8G1G

www.fcpeuro.com

Reactivating an old thread, but I had it bookmarked on all the different VW coolants. Just to clarify, the Pentosin SF coolant is G12+. FCP Euro is mistaken that it is regular G12. I picked up a bottle and on the back it states in the approvals section that it has "VW TL 774 F (G12+)". The back label photo in the FCP Euro is too small to read it clearly, but the Pentosin SF is G12+. Not sure if regular G12 is available anywhere any longer.

Still better than G13....

 

[d2freeman]

This video explains all the VW coolant.

 

[Zambee500]

Well, apparently i didn't act quickly enough 6 weeks ago. Although by that point it was probably already too late. Spouse drove the CKRA from Georgia to N. Carolina and back weekend before last. Threw a P2457 about 2 hours from home. First taste of winter hit last week and sure enough no cabin heat. Dropped it off at the dealership because it's still covered under dieselgate warranty, and it's been there for a week now (did get a loaner, but only after escalating to dealership manager after two "service advisors" insisted they don't do loaners anymore and their contract with Enterprise had expired and any reimbursement for rental/loaner car was between me and VWoA. After escalating, magically a customer returned an Atlas loaner vehicle from the loaner fleet that the "service advisors" had just told me no longer existed).

Anyway, been at the dealership for a week for a new heater core, and instead last evening I get a $1150 quote for unrelated "Needs immediate attention" repairs that they said are "required". The quote includes $650 for a new coolant expansion tank, which is a $48 part OE from another local dealership and 0.6 hours book time. Okay, another $25 for a replacement cap. Seriously, $75 parts and 36 minutes labor and they want $650. After I declined that and a serpentine belt replacement ($225), all of a sudden I need a new battery for $300 with a write-up that the car won't start and they have to jump start it each time they take it in and out of the shop. VW dealership in Tampa installed the OE battery ~3 years ago and it's never needed a jump and given me zero problems...until I dropped it off at the dealership. I declined all three items, so we'll see if today they say they cannot do the warranty work without doing the additional work.

As OH has noted several times, these warranties are worthless. Not even worth the hassle factor. I hope this warranty replacement heater core (assuming they do the work) makes it to February when I'll have the alphabet soup deleted and go ahead and have the coolant system flushed and replace the heater core again preemptively and have it filled with G12+.

Reactivating an old thread, but I had it bookmarked on all the different VW coolants. Just to clarify, the Pentosin SF coolant is G12+. FCP Euro is mistaken that it is regular G12. I picked up a bottle and on the back it states in the approvals section that it has "VW TL 774 F (G12+)". The back label photo in the FCP Euro is too small to read it clearly, but the Pentosin SF is G12+. Not sure if regular G12 is available anywhere any longer.

Still better than G13....

 

[eugene89us]

Let us know how it goes. Hope they get it done quickly.

 

[Zambee500]

So I picked up my car yesterday with new heater core replaced. Battery was indeed dead, and had to jump start it in the lot to get me on my way. But I think the dealership left a light or something on inside the cabin for a week, and ran the battery completely dead, and of course they'd have to keep jump-starting it if they never recharged it or drove it for any meaningful amount of time to allow the battery to recharge. So after getting home yesterday I hooked it up to my battery smart charger at home and charged to 100% and the car started fine this morning. So we'll see if I really need a new battery.

As to the heater core, the "service sales advisor" said verbally they did a coolant flush and replaced heater core and also "some gasket". The service tech write up on the invoice explained the DTC and diagnosis and repair, and he just indicated he drained coolant, replaced heater core, and performed vaccuum fill to refill coolant and ran engine to operating temperature and all heat functions work properly. So it's not totally clear to me if they really did a flush. The TSB for the P2457 DTC says they are supposed to run a full coolant flush twice before replacing the heater core and refilling with coolant a third time, using 3 gallons of coolant mix. But no mention that they did this, and the invoice just indicates 1 gallon of coolant.

Also, the coolant refill was G12 Evo (G-12E-100-1G-CON). So this is the glycerin based version of G12 that replaces G13? Isn't it the glycerin in G13 that is thought to be causing the clogging of heater cores? Also, what can be safely mixed with G12 Evo? I have G13 concentrate and about a half gallon of plain G12 50/50 mix on my garage shelf. I don't know why VAG had to make it so confusing with 4 different versions of G12 and also G13, some of which are compatible with each other and some aren't. The nomenclature sucks and is needlessly confusing.

Last point, I also noted in the invoice that the part number of the heater core now ends with suffix "C" so perhaps there has been some revision or improvement to these heater cores. The older TSB and prior comments mentioned the part number ending in "B".

Let us know how it goes. Hope they get it done quickly.

 

[Zambee500]

I found this 2022 TSB on VAG coolant types: https://static.nhtsa.gov/odi/tsbs/2022/MC-10208466-0001.pdf



Discontinuation and mixing of Volkswagen approved engine coolants.

Technical Background

Coolants G11, G12, G12+ and G12++ and G13 have been replaced by a newly introduced G12Evo coolant.


Note:
GEN III EA288 TDI (MY2015 2.0L TDI CVCA and CRUA) MUST continue to use G13 coolant.

Production Solution

G12Evo coolant has been introduced as the factory fill coolant in current production.

Service

G12Evo coolant is backwards compatible with all engine concepts, EXCEPT for the GEN III EA288 TDI (MY2015 2.0 TDI CVCA and CRUA).

Note:
The GEN III EA288 TDI (MY2015 2.0L TDI CVCA and CRUA) MUST still use G13 coolant.


Tip:
If you suspect that a vehicle has been filled with the incorrect or non OEM coolant, the cooling system should be drained using the repair manual procedures in Elsa and then filled with the correct coolant. Cooling system drain and fill due to incorrect or non OEM coolant mixing is not covered by warranty.

Note:
When mixing G12Evo with G11, G12, G12+, G12++ or G13 the coolant becomes brown, this is normal and does NOT necessitate a coolant system drain and fill.

 

[Zambee500]

Maybe this is where I found it. Lol. Thanks Nuje!

There's a technical bulletin to the effect that the new "official" VW coolant (can't remember the number) could be mixed with the G13 coolant, but the coolant could/would turn brown, and that this was normal, and not at all a problem.

 

[Lex Tdi]

Its been said often, and seems to be proven in my case that the only way to avoid collant issues is to delete... exteneded regens from the fix cook the coolant and break it down. I deleted, because like you, i found out warrenties are useless if the same thing will occur again and again. Since deleteing well over 120,000 miles ago i have had zero heater core or coolant issue (really any issues for that matter). As someone who drives a lot realiability was worth a lot more than a useless warrenty.

As OH has noted several times, these warranties are worthless. Not even worth the hassle factor. I hope this warranty replacement heater core (assuming they do the work) makes it to February when I'll have the alphabet soup deleted and go ahead and have the coolant system flushed and replace the heater core again preemptively and have it filled with G12+.