Newbie TDI owner...

I bought a 2014 Passat TDI SE about a month ago... and I’ve had a few pesky things appear. I’ve tried to educate myself on the regens - I have a 50 mile commute one way each day (half of it is stop and go traffic). This has happened 3 or 4 times on the evening ride home... the engine temp gauge will fluctuate between 190 and 210... when I arrive home and park... the fans are going like it’s trying to do a regen?
Just curious if there is a relation or just totally nothing to worry about?!

Regens involve injecting fuel into the exhuast to raise the temperature of the exhaust hot enough to burn off particular matter in your DPF. As such, it does effect the engine coolant temperature. The fans come on after you shut off the engine to dissipate heat in the engine bay.

If your temperature is fluctuating and your engine cooling fans are on after you arrive home you may have an engine cooling problem. Is your coolant level full? lots of particulate in the reservoir? are you losing coolant? where? is your car due for a water pump change - how many miles on it?

Regens don't happen all that often - maybe every 500-1000 miles or once a month in my experience. My coolant temperature has never exceeded 190 degrees (the middle mark on the guage) under any circumstance after 34,500 miles, regen or not, climbing over mountains, etc. Never.

To be certain as to why your engine cooling fans are on, get an app like EngineLink for your phone with bluetooth connection to OBDII port and check your exhaust temperature when the fans are on and check the engine coolant temperature too. If your gauge reads hotter than 190 I am thinking you have an overheating problem.

The car has 59,200 miles on it. I just bought it a couple of weeks ago... I took in to the dealership last week due to the AC not operating... so, the diagnostic on that is a new compressor. I asked them to do an inspection on the fluids and all. Said everything was fine. As far as service records - the only thing I have is where the car was modified for emissions back in Jan 2020. I really hate to say this but I’m leaning toward trading it back in or selling it. I’m going to drive myself crazy worrying about it all!

My 2 cents: sell it or trade it back in.

Regens happen about every 250 miles not 500 to 1k miles. Sooner if you are driving stop and go. An app like VAGDPF and a BT OBDII dongle will let you monitor these regens and know when they are occurring. Not unusual for the temp to run up that high during a regen either. Get the app and dongle and monitor it after the repair is done on the AC. No need to freak out or sell it just yet. Read up here on the regens and what you can do to let them happen when needed and other info about them. Knowing when they are occurring and letting them happen when needed will greatly reduce your stress!

Yeah coolant gauge is very very buffered, what you see as 210 is prob closer to 230 or so.
The Gen2 of the 12-14 Passat are known to have coolant clogging issues.

My ‘14 regens every 330-370 miles, my commute is 65 miles a day, 90% at 70 mph. The temp gauge stays at 190 on mine, actual temp is usually 205-220 according to my polar fis.

If you bought it with CPO warranty, they will fix it. If not try to see if it is something that diesel gate warranty will cover?