Heat Only on Driver Side - clogged heater core

[gwalter]

I do the same thing ever since my heater core was replaced. I run the heater periodically (fairly often) during summer and..... so far..... I still see the dash vents continue to put out approx 175F.

 

[aja8888]

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?

The heater core is open to the coolant flow at all times.

 

[tjsadler]

I'm having the same thing with my wife's 2014 Passat. Threw a CEL and when I scanned it came back with P2457 and when I test drove it for half an hour there is no heat at all. Just over 54,000 miles and under two years old. SO frustrating. There is NO WAY the heater core should fail on this many new cars. My problem is that the nearest vw dealer is 5 hours away. I'll be going for a training class for a week later this month and I'll be right by several dealers in Sacramento. For those of you who were successful in getting VW/dealer to cover this repair what did you do to convince them? Any tips would be appreciated!

 

[VernK]

Just a comment on the pictures of the two cores. Most of the difference can be attributed to the style of exchanger. The Passat is a parallel design with a inlet & outlet header, the other is a series design. The Passat core is more efficient (more surface area per unit volume of core) but also more susceptible to passage clogging, as VW seems to be finding out.

Yours
Vern

 

[TDI Jim]

Add another 2014 Passat TDI SE to the list and just like tjsadler above, mine just coded for:
8215 EGR System
P2457
Insufficient Cooling Performance
Fault Priority:2
Fault Frequency: 22
Mileage: 105,802 kilometers, or about 66,000 miles

I checked with a ex-VW service technician that started his own business, and he googled the P2457 code and said, "Let's check and see if you have heat". We did and no heat, which means a clogged heater core, so this is apparently a more common problem than I thought. I have 3 B4's with over 330,000 miles and did not have to replace the heater core in them yet. This code just came up on my drive back from New Hampshire to Baltimore this past Tuesday after Labor Day, so need to get it taken care of as it will be in the 40's at night in WV where I am leading a trip this weekend. Thanks for posting this and hope the information helps other Passat owners.

 

[VeeDubTDI]

The heater cores aren't failing. The coolant is what's failing. Additionally, the coolant appears to be blocking up other coolers (see above EGR insufficient cooling code), and perhaps even the oil cooler.

 

[Softrockrenegade]

VeeDub , can you elaborate on what you mean by coolant failure. It's the first I'm hearing of this. Why would it only affect the nms passats ?

 

[VeeDubTDI]

Seems to me like it is getting unstable and congealing. Perhaps something with G13? I really don't know.

 

[TDI Jim]

No Heat and EGR Insufficient Cooling Performance code P2457

I was turned down by my local dealer and called V of A today and after due consideration of the issue, scheduled an appointment for me on Monday at said local dealer. I will update what I learn. The fact VW has already redesigned the heater core says something to me. There is no noticeable evidence of congealing of the coolant, which is still clear and pink.....and I am a chemist by trade, but we will see what the dealer says.

 

[tdiatlast]

TDI Jim:The replacement heater cores have a "b" suffix, but I was not aware of any redesign. Do you have a source for this information, or was your statement based on the change in the part number?

 

[jrm]

Does anyone know what changed from G12++ to G13? Both are Organic Acid Technology coolants.

 

[TDI Jim]

tdiatlast: It is based on the "b" suffix, plus when I spoke to VW of A yesterday they did not deny the redesign.

 

[big_ole_truck]

Great, something else to worry about. Screw it, I'll drive more, worry less.

 

[tdiatlast]

tdiatlast: It is based on the "b" suffix, plus when I spoke to VW of A yesterday they did not deny the redesign.

Yo...VeeDubtdi guy...are you paying attention? Didn't someone send you a clogged heater core? Did you ever cut it open? I think you posted photos, comparing the core to an earlier model, but not an actual side-by-side comparing "a" and "b" versions.

When I had mine replaced (2014NMS), the tech said they looked identical, but he neglected to hold the clogged one for me to examine. VWoA wanted it back (as with all warranty replaced parts)

 

[dogger37]

I'll throw this one out there too.... Changed my coolant this weekend and it had grainy, white crystal style contaminates in it. There is no way they came from the external environment so somehow a reaction must be taking place within the system...

People who are smarter than me I'm all ears!

 

[jrm]

Hmm, history does repeat itself- same thing happened to GM in 1996 when GM first came out with a OAT coolant branded dex-cool (very close to G12 and G13) as even old iron block 350's where gumming shut. (im positive oilhammer would know all about this) My father bought a 1996 truck cheap, due to the dex-cool lawsuit. Lucky for me this was when I was getting my degree in automotive and we swapped the coolant out in his truck every other year until the new Dex-cool formula hit the shelf and its trouble free to this day- 20 years later.
So- time to dump the coolant in our NMS, head over to ID parts to pick up a couple gallons of G13 Coolant changes are soooo easy no reason not to

 

[TDI Jim]

I had the parts manager confirm there is no difference between G-12 and G-13, only a name change and there was a redesign of the heater core between the "A" and "B" suffix codes.

For the update on my wonderful dealer/VW of A experience:
The dealer wanted to charge me $130 for a diagnostic charge for my heater core issue, which I refused to pay, so the dealer and VW of A did nothing to help me. I spoke to an experienced VW/Audi mechanic and he told me to use compressed air to blow the heater core out first with a good seal between the pipe from the heater core and air gun, so will try it this week. If no luck, I will need directions on how to replace the heater core, thanks guys and hope this information helps.

 

[tjsadler]

An update on mine... I took it in to a dealer in Folsom CA last week. They diagnosed it and said that it was the heater core and wasn't covered under any warranties. I pointed out to him that California warranties the EGR system for 7/70,000 and that since this was part of that system it would logically be under warranty. ( I have 55,000 miles ) He requested a "courtesy consideration" from VWoA and they covered it 100% so it seems like it's just a crap shoot as to whether they cover them or not. If they say no at first I would definitely keep pushing and calling VWoA and respectfully asking them to step up to the plate for you. I'm currently asking them to just take the car back and give me my money so we'll see how that goes...

 

[sdeck]

maybe this is a good time for eliciting some "good Will" from VWoA, since they aren't going to be selling any new ones, they may want to keep their current customers happy.

 

[tdiatlast]

^^^sdeck: Well, I have an opposite take on this. I think everyone in the VW corporate community is going to have to go on an austerity campaign, as they will now be hemorrhaging money.
They WILL have to rebuild trust, though, so it's going to be rough going for all concerned for the immediate future.

 

[tdiatlast]

An update on mine... I took it in to a dealer in Folsom CA last week. They diagnosed it and said that it was the heater core and wasn't covered under any warranties. I pointed out to him that California warranties the EGR system for 7/70,000 and that since this was part of that system it would logically be under warranty. ( I have 55,000 miles ) He requested a "courtesy consideration" from VWoA and they covered it 100% so it seems like it's just a crap shoot as to whether they cover them or not. If they say no at first I would definitely keep pushing and calling VWoA and respectfully asking them to step up to the plate for you. I'm currently asking them to just take the car back and give me my money so we'll see how that goes...

I don't understand how the heater core is part of the emissions system. Please explain.

 

[tjsadler]

I don't understand how the heater core is part of the emissions system. Please explain.

The EGR cooing circuit. The heater core is part of that circuit apparently. In most cases in warmer climates the lack of heat isn't noticeable at first. But the clogged heater core triggers a CEL that gives a code related to the EGR system. The only way to fix this fault in the EGR system is to replace the heater core.

 

[tdiatlast]

Using the same logic, the engine's radiator is part of the emissions system? I still don't get it. I understand coolant is used for the EGR, but following this logic, if the radiator fails, it could be covered under the emissions warranty???

 

[tjsadler]

Using the same logic, the engine's radiator is part of the emissions system? I still don't get it. I understand coolant is used for the EGR, but following this logic, if the radiator fails, it could be covered under the emissions warranty???

I'm not saying I'm necessarily totally correct. What I'm saying is that this problem causes a fault code that refers to the EGR because it's part of that system. As such, if your state also has a longer emissions warranty period you might be able to argue that. In my case they gave me a "courtesy" repair. In my experience that usually means that they either recognize that there is a problem that should be warrantied but they don't want to admit it because then they'd have to fix it for everyone, or they recognized that I was the type of calm, respectful, but obviously persistent enough that I wasn't going to take no for an answer type of person that they'd rather not spend days arguing with. Either way I'm just trying to help you with trying again to get them to cover it so you don't end up wasting an entire weekend neck deep in your dashboard.

 

[tdiatlast]

tjsadler: Got it. "...calm, respectful, but obviously persistent..." is my demeanor at all times at the dealer. (too bad I can't maintain the same attitude with my kids)

TDI Jim: sorry to hear of your continued troubles. They really should be replacing this for you, as this is a known weakness in the NMS Passat.

 

[4thVWDsl]

Me Too.....

Add myself to that list. 2014 NMS, 41000 kms. No heat. I froze this morning, and I had to turn the A/C on to see through the windshield. I'm seriously beginning to regret buying this car. I have had turbo/intercooler problems, and since the last ecu flash for the emissions, the thing is constantly in regen. It seems like every time I drive it, it goes to regen and runs the fan after shutdown. Now no heat.

With all this dieselgate stuff going on I'm seriously beginning to question the liability of continuing to own this automobile. If it is casting sand that is plugging these heater cores, I can tell you, expect more problems later with the water pump. Seals don't like sand.

 

[mountain-valleymotors]

Well we have done two of these heater cores in the last two days in my shop. I can confirm that it is indeed coolant contamination that is plugging them up. The first one that we took out wasn't actually plugged. We just assumed that it was because there was no heat on the passenger side. After we replaced it, we still had no heat because the blend door actuator was bad. So we replaced the actuator and all was well.

We had another car with no heat on the passenger side and this one we confirmed was plugged up heater core.

So I have two used heater cores with about 85k miles on each of them. The one is plugged up and the other is not. The one that is plugged up has a copper colored residue inside and the one that is not plugged up is clean aluminum inside. I back flushed both of them and ran hot water through them to check temperatures across the core. The non-plugged one only drops 6 degrees from one side to the other, the plugged up one drops over 30 degrees from one side to the other.

I did manage to get some brown colored junk out of the plugged up core but not enough to clear it. I am thinking that we need to flush the factory fill anti-freeze out of these cars and replace it with G12. The car that had the clean heater core, we had replaced the water pump on earlier and replaced the coolant with G12. The one with the plugged up heater core was still on factory fill of G13.

 

[tdiatlast]

^^^Was there a brown coating on the coolant reservoir, and was the coolant discolored?

 

[mountain-valleymotors]

There was no brown coating on the reservoir but there was some brown sediment in the bottom of the reservoir and some specs of flaky brown stuff floating in the coolant.

 

[jrm]

well ill be swapping mine this weekend, camera in hand- I assume the rad has a nice drain plug?