Heat Only on Driver Side - clogged heater core

sdeck

Veteran Member
Joined
Aug 25, 2006
Location
Northern Colorado Front Range
TDI
2003 Jetta, 253K, 01M, DLC520s, VNT-17(sold); 2014 Passat SE 6M, 61,000 miles (Feb 16 buyback date)
just picked it up. I got to look at the old core, but it was being sent back to VW. From the outside, it looked like really thin passages. Much narrower than the radiator. Tech said there is likely to be a recall as many start leaking, apparently from the increased pressure due to the clogging. He "thinks" it was a design flaw and "thinks" that they tweaked the design, but who knows. He told me they flushed the lines (whatever that means) and put in the new core. I noticed two things with the new core:
1. I get heat on the passenger side
2. Intermediate temp knob positions actually seem to regulate temps between full hot and cold. Before, I had to keep moving the knob around because it was either full hot when all the way up or too cold in the middle. Maybe I'm just imagining it, but regardless, the wife is happy now.
 

tdiatlast

Top Post Dawg
Joined
Jan 21, 2009
Location
Fort Worth, Texas
TDI
2009 Sportwagen (boughtback); 2014 Passat TDI SEL (boughtback)
Thanks for the update. Glad you've got your car back.

Any idea what modifications have been made for the replacement heater core? Did you/could you ask your service advisor? Hopefully there have been a redesign, but we won't know that until we can see OEM and replacement side-by-side.
 

sdeck

Veteran Member
Joined
Aug 25, 2006
Location
Northern Colorado Front Range
TDI
2003 Jetta, 253K, 01M, DLC520s, VNT-17(sold); 2014 Passat SE 6M, 61,000 miles (Feb 16 buyback date)
I asked, but he didn't know any specifics and wasn't even 100% sure it has been redesigned. He did say that he hasn't heard of any replacements coming back or having issues, so they "must have" changed something.
 

dogger37

Veteran Member
Joined
May 28, 2012
Location
PA
TDI
2012 passat
2012 passat with 102,500 just started having this issue as well
 

phat02jetta

Active member
Joined
May 8, 2005
Location
Western NY
TDI
Jetta, 2002, Black - Passat, 2013, Black
just picked it up. I got to look at the old core, but it was being sent back to VW. From the outside, it looked like really thin passages. Much narrower than the radiator. Tech said there is likely to be a recall as many start leaking, apparently from the increased pressure due to the clogging. He "thinks" it was a design flaw and "thinks" that they tweaked the design, but who knows. He told me they flushed the lines (whatever that means) and put in the new core. I noticed two things with the new core:
1. I get heat on the passenger side
2. Intermediate temp knob positions actually seem to regulate temps between full hot and cold. Before, I had to keep moving the knob around because it was either full hot when all the way up or too cold in the middle. Maybe I'm just imagining it, but regardless, the wife is happy now.
I have always had the same problem with intermediate temps, never could get a stable temperature out. I started thinking the blend door was flopping around in there. I hoping I'll see the same effect as this was one of my biggest pet peeves about this car.

I'm driving a loaner while parts are on order, they have the heater core, but they didn't have the seal/gaskets to go with it! Apparently they used to ship as a kit, but something changed and now they are separate items.
 
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tdiatlast

Top Post Dawg
Joined
Jan 21, 2009
Location
Fort Worth, Texas
TDI
2009 Sportwagen (boughtback); 2014 Passat TDI SEL (boughtback)
FYI: Just spoke with parts manager at Autobahn VW in Ft. Worth. He says there is now a "B" part number on the heater core.

I know parts numbers change all the time, but I'm now wondering if this "B" number is for a modified part?
 

Not_Agn

Veteran Member
Joined
Oct 23, 2011
Location
Northern IL
TDI
2013 Passat Se TDI
Just picked my car up. Half way home I can feel the difference between the driver and passenger side vents. Dealer is leaning towards "it's normal". They are telling me a 20 degree difference is acceptable. Not sure I'm buying that. Running the defrost you can slide your hand across and feel the change. The loaner car (2015 passat tdi) really didn't feel that much different across the vents. Are the 2015 different as fast as the heating system?
 

tyrntlzrdking

Banned
Joined
Feb 3, 2013
Location
Michigan
TDI
2013 Passat TDI SE 6MT
2013 SE with about 10,000 miles. Just noticed I also have no heat on passenger side floor.
Hope they don't tell me its "normal".
Girlfriends feet became so cold she had to sit Indian style to lift them up onto seat for warmth. Not good.
 

sdeck

Veteran Member
Joined
Aug 25, 2006
Location
Northern Colorado Front Range
TDI
2003 Jetta, 253K, 01M, DLC520s, VNT-17(sold); 2014 Passat SE 6M, 61,000 miles (Feb 16 buyback date)
FYI: Just spoke with parts manager at Autobahn VW in Ft. Worth. He says there is now a "B" part number on the heater core.

I know parts numbers change all the time, but I'm now wondering if this "B" number is for a modified part?
The new one they installed on mine had a "B" at the end of the part # on the invoice
 

ABS

Veteran Member
Joined
Mar 17, 2003
Location
South Central Minnesota
TDI
2014 Passat SE TDI, 6MT
Picked up my car on Saturday after the dealer finished the heatercore R&R late Friday. The car is kicking out heat like it did last winter across all the manual controlled blend settings.

Replacement part number 561-819-031-B. Tech indicated VW did redesign and changed some orifice diameters/flow path inside the core, and the "B" does in fact designate the new core design. Unfortunately, I was unable to get my hands on the core for some destructive testing. I did however, try to blow air through the old core, and it was like blowing through a cocktail straw.
 

phat02jetta

Active member
Joined
May 8, 2005
Location
Western NY
TDI
Jetta, 2002, Black - Passat, 2013, Black
Thanks for the part #. I just called and confirmed that I'm getting the new version installed, if the seals/gaskets ever come in. I'm up to 450 miles on the loaner so far.....
 

Steve93015

Member
Joined
Jan 18, 2015
Location
Fillmore, Ca
TDI
2012 Passat TDI SEL
I'm experiencing the no passenger side heat on my 2012 Passat TDI SEL. VCDS shows no codes. Seems like some progress is being made if VW has a new part number for the heater core and people are reporting that the problem is cured by the replacement. Hope to see a recall soon. I'm with ABS, I'd like to see a destructive test to determine what why only one side of the core fails. Based on my reading it's always the passenger side also.
 

ABS

Veteran Member
Joined
Mar 17, 2003
Location
South Central Minnesota
TDI
2014 Passat SE TDI, 6MT
My dealer covered the repair in full and provided a loaner for three days. My mileage when I rolled into the service center last Wednesday was at 47,844 miles.
 

Not_Agn

Veteran Member
Joined
Oct 23, 2011
Location
Northern IL
TDI
2013 Passat Se TDI
Dealer covered the heater core replacement. Provided me a loaner. Charged me for a coolant flush /cleaning. Said it's recommended at 50000 miles. Told them it's vw problem that my heater core is plugged and that they should normally do a flush. He said they would replace the part and top off. I said it's bull****. All they could tell me is they are sorry. Got my car back sat. Passenger side wasn't ice cold like before, but wasn't hot like the drivers side. Got them to keep it and check it out today. They put me back in the loaner.
 

sdeck

Veteran Member
Joined
Aug 25, 2006
Location
Northern Colorado Front Range
TDI
2003 Jetta, 253K, 01M, DLC520s, VNT-17(sold); 2014 Passat SE 6M, 61,000 miles (Feb 16 buyback date)
I'm experiencing the no passenger side heat on my 2012 Passat TDI SEL. VCDS shows no codes. Seems like some progress is being made if VW has a new part number for the heater core and people are reporting that the problem is cured by the replacement. Hope to see a recall soon. I'm with ABS, I'd like to see a destructive test to determine what why only one side of the core fails. Based on my reading it's always the passenger side also.
The cause is that the driver's side is the coolant inlet side. If flow is restricted inside the heater core, the blowing air blowing cools the driver's side first. When that coolant gets to the passenger (outlet) side, its already cooled down. In unrestricted normal flow, the coolant flows faster than the air can cool it so it is still hot when it hits the passenger side.



 
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Steve93015

Member
Joined
Jan 18, 2015
Location
Fillmore, Ca
TDI
2012 Passat TDI SEL
Thanks Sdeck for the graphic. Anyone cut away a heater core to see the flow paths? What's causing these things to plug up? I can speak to my car and maintenance, which was done to schedule, so I'll eliminate neglect as being the problem. Incompatible material to coolant? How plugged up must the heater core be to stop all heat from the passenger side? Seems very odd to me.
 

radunegru

Well-known member
Joined
Feb 23, 2013
Location
Middle Village NY ( NYC)
TDI
2013 Passat TDI
Just picked up the car at the dealership 37899 miles, little over warranty.
Dealer covered all including 11 days loaner. Great service also did the 23 N5 recall ( software Update). Very pleased with VW.
Apparently heater core was clogged on passenger side as per previous posts description.
 

tdiatlast

Top Post Dawg
Joined
Jan 21, 2009
Location
Fort Worth, Texas
TDI
2009 Sportwagen (boughtback); 2014 Passat TDI SEL (boughtback)
Thanks Sdeck for the graphic. Anyone cut away a heater core to see the flow paths? What's causing these things to plug up? I can speak to my car and maintenance, which was done to schedule, so I'll eliminate neglect as being the problem. Incompatible material to coolant? How plugged up must the heater core be to stop all heat from the passenger side? Seems very odd to me.
There's no "maintenance" on the heater core, and coolant change/flush isn't even listed on VW maintenance schedules.

Was there any discoloration to the coolant with any of these failed heater cores?
 

Not_Agn

Veteran Member
Joined
Oct 23, 2011
Location
Northern IL
TDI
2013 Passat Se TDI
Heard from the service manager last night. He now says he believes there is a blend door issue. Acknowledged that there is still a problem after heater core replacement.
 

Not_Agn

Veteran Member
Joined
Oct 23, 2011
Location
Northern IL
TDI
2013 Passat Se TDI
Just heard from the service manager again. Told me that vw wants him to replace the heater core again, as well as some other flushes. 7-10 days for the core.
 

VeeDubTDI

Wanderluster, Traveler, TDIClub Enthusiast
Joined
Jul 2, 2000
Location
Springfield, VA
TDI
‘18 Tesla Model 3D+, ‘14 Cadillac ELR, ‘13 Fiat 500e
My coolant was pristine, so no, I did not see any discoloration at all.
That would indicate to me that there is some loose material in the system from engine manufacturing. Casting sand/stuff.

This is what it looks like in a Ford 6.0...



And this is what it does to a 6.0 oil cooler...

http://s1054.photobucket.com/user/mmasid/media/2012-03-11_13-34-14_164.jpg.html

Notice how it gets in there and clogs all of the coolant passages, essentially rendering the oil cooler ineffective. I think this is the same thing that is happening to the Passat heater cores. The real question is: if this is happening to the heater cores, is it also happening to the oil cooler and transmission cooler?

It sure would be nice if someone could cut open a heater core and post some pics. (I'm looking at you, Silver Ghost). ;)
 

Steve93015

Member
Joined
Jan 18, 2015
Location
Fillmore, Ca
TDI
2012 Passat TDI SEL
My coolant looks good. What I intended to say is that if the VW scheduled called for fill/flush I would have had it done.

I saw a video on a VW mechanic doing a heater core flush on previous model. Basically used a bucket and pump and did a round-robin in both directions with CLR for a hour, then flushed with water, repeated flush, then flushed with distilled water. I might not hesitate to use CLR on the heater core, but not sure I want to run that through the entire system.
Has anyone done a full system flush and if so, what results did you see? Did you find casting sand or junk in the flush water? Curious.
 
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