Hey everyone,

So I was driving my 2011 S4 the other day and the AC started to blow hot and the engine temps started to rise. Had plenty of coolant in my overflow tank. Did a little research, and suspected the thermostat was stuck closed.Had it towed to the stealership, and that's indeed what it was. I had them replace it, then was going through some paperwork I had from the previous owner the very next day and came across a letter he'd received from Audi of America regarding a service action campaign: Campaign 19H3/4F - Engine Thermostat Replacement. (same on as here: https://www.audiworld.com/forums/s4-.../#post24486726)
The letter has my VIN at the top of the page and states that I can take my vehicle in to have it swapped at no charge, or get reimbursed if I've already had it swapped at my own cost.So I call my dealership and they say that they can't see any current or past recalls, service action campaigns, etc. for my VIN apart from an ECM flash that was completed in August of 2014. I also entered my VIN on Audi Recall Services by Vehicle Identification Number and it shows the same thing.

I've read every thread I've found so far on it, and it sounds like a ton of people got this letter and had this taken care of at no cost to them without any pushback from the dealer.I've found this in a number of places:

Thermostat failure
Recall issued for certain cars as "Service Action Campaign 19H3/4F"
USA - 2010-2011 S4
WAU_G_FL_AA007653 – WAU_G_FL_BA055169
Production date: June 05, 2009 – October 04, 2010

My VIN falls within the VIN range. My production date is 08/2010. My VIN is on the letter I have from Audi. My car experienced the issue. Yet Audi's website shows nothing, and two different dealerships tell me that there are no open or past events for my VIN.

Any ideas anyone?

Also, can anyone tell me what the original part number and the updated part numbers are?