14 Passat heater core_scammed by dealer?

Let me start off by saying this is in regards to my personal 2014 Passat tdi dsg. I was having the dreaded heat from drivers side only. Which turned into almost no heat at all. The check engine light came on for egr cooling low efficiency. The car was taken to the local VW DEALER and they stated it was covered under the cpo warranty. Great news.
The heater core they said was in stock and they would need 4 hours to replace and allowed me to schedule a time. Well last week was that day. I picked the car up and the heat seemed great. Until i started checking closely, the heat on the passenger side is still 15 degrees cooler. Also this is the non dual zone system. I started looking around the car and it doesn't appear that anything interior was touched.
My question is. Does anyone have any experience or opinion on this specifically, is it really possible the dealer would have just flushed the core to produce heat, and hope i would go away happy? Would they really do something so low or am i overthinking this entirely. I just don't want to call them up if it's entirely normal to have a substantial temp variation from side to side. Thanks everyone in advance

If it's all warranty take it back to them and let them sort it out.

You do not have to remove the dash (or much of anything else) to do the heater core in the NMS. It is accessed through a little trap door down by the pedals. So from the driver's seat, nothing would or should have been "touched".

Did you measure the temp difference left to right when the car was new? Or checked it against another NMS? It is not uncommon for a slight temp difference at certain ducts. Not saying this is a problem with your car or not, but it might be normal given the fact that the heater core inlet tube is on the driver's side of the car.

oilhammer said:

You do not have to remove the dash (or much of anything else) to do the heater core in the NMS. It is accessed through a little trap door down by the pedals.

Click to expand...

That's nice they finally did that.

Seems it started a while ago, actually. I know the post-B5 Passat era Audi A4 is like that, as well as all the A5 chassis Volkswagen/Audi products.

So no more starting with the heater core and building the vehicle around it?

Damn...that would be nice. It's on 1 job I refuse to do again on a B4.

Simple thing to check is color of coolant, pink is fresh, failed heater core is more clear/orange. I can check temperature on my vents if you still have a question, mine is an sel premium with dual zone.