Jetta TDI MKVI
I am posting this as to maybe help another since the winter is coming soon. I had noticed last winter that my heat was very low. Basically to the point that it was cool coming from the center vents, but out of the side vents it was warmer. This is what was confusing me. I lived with it because it doesn't get that cold in North Texas and I have heated seats. So, when I replaced the timing belt and flushed the coolant (which had crap floating in the reservoir). I took the lines off of the heater core and ran water through it and I saw clean water and nothing obvious that showed the heater core to be clogged. Put everything back together with no help. During the spring time I started getting EGR COOLING faults and a MIL light (unsure of the fault code itself). I would clear the fault and it would go away for a month. The fault started becoming more frequent over time. From what I found, this is definitely a heater core issue because the coolant runs through the heater core before going to the EGR valve. IF the heater core is blocked, the flow will not be efficient enough for the valve. I replaced the heater core and have had no problems since. As a matter of fact, the heat is so damn hot I never put it on full heat. So anyone with a TDI that is having an EGR COOLING issue, take a look at the heater core. I also read that this is a common issue with the Volkswagens'. At the time I had between 120-130k miles when i replaced the heater core.
I am posting this as to maybe help another since the winter is coming soon. I had noticed last winter that my heat was very low. Basically to the point that it was cool coming from the center vents, but out of the side vents it was warmer. This is what was confusing me. I lived with it because it doesn't get that cold in North Texas and I have heated seats. So, when I replaced the timing belt and flushed the coolant (which had crap floating in the reservoir). I took the lines off of the heater core and ran water through it and I saw clean water and nothing obvious that showed the heater core to be clogged. Put everything back together with no help. During the spring time I started getting EGR COOLING faults and a MIL light (unsure of the fault code itself). I would clear the fault and it would go away for a month. The fault started becoming more frequent over time. From what I found, this is definitely a heater core issue because the coolant runs through the heater core before going to the EGR valve. IF the heater core is blocked, the flow will not be efficient enough for the valve. I replaced the heater core and have had no problems since. As a matter of fact, the heat is so damn hot I never put it on full heat. So anyone with a TDI that is having an EGR COOLING issue, take a look at the heater core. I also read that this is a common issue with the Volkswagens'. At the time I had between 120-130k miles when i replaced the heater core.