Shouldn’t VW cover replacement of thermostat under warranty if PDF keeps coming on?

Purchased last year a 2013 beetle TDI. Car is great, only problem is the particle displacement filter light keeps coming on. Took it in to a dealer (did not get it from a dealer), and they said it needs to be regenerated. Two months later it happened again, four months later it happen again. This time they said that it might be a faulty thermostat and the best thing for us to do would be to spend almost two thousand dollars replacing the thermostat that may or may not be causing a problem with the PDF. I argued with them that I felt that it should be covered under the emissions warranty. They said no. We weren’t overly happy with the dealer as a whole and their service anyway so I want to take it somewhere else as the light has come on again. But what I wanted to ask out there is if anybody’s had a similar problem and what the general opinion is as to warranty coverage.

I’m obviously not a mechanic but it seems kind of common sense that if the PDF needs to be regenerated the thermostat needs to be working. My understanding was that the PDF was covered as part of the whole emissions scandal issue so wouldn’t the thermostat be covered as well. It seems all connected.

This is my daughter’s first car she bought on her own. She’s always wanted a beetle but has maxed out paying for the car and can’t afford thousands of dollars in repairs right now. We need to get it taken care of, she’s worried about damaging the engine. Any input would be greatly appreciated.

First welcome to tdiclub! Second it is dpf (diesel particulate filter). Yes it should be fully covered by the warranty. Read your document and be aware of what it states "before" going in and take it with you. Anything that sets a check engine light is covered except the trans.

What kind of driving do you do? Lots of short distance isn't good for these cars without the driver paying attention to regens.

If the thermostat was failing to the point of it being an issue, the ECU would flag a DTC. Coolant temp is monitored, and if it is not getting up to operating temp properly, you'd know.

It sounds like the type of driving happening is not doing well with the DPF. Lots of short trips, lots of idle time, lugging the engine, driving in too high of gear at too low of RPM, and not ever getting out on the open highway for a bit are all contributing factors.

If you are doing short trips and such there are tools out there that will let you monitor the regen status and allow you to not interrupt a regen when one is needed. If you learn and keep up with it it will solve a lot of issues for that kind of driving. VCDS can do this as well as Torque and VAGDPF. Lots of info here on these if you search a little.

Very simple to purchase a scan gauge, plug it into the OBD port and monitor coolant temp. I would take the car for a long, hard drive on the highway.

Thank you guys for all the info. I should mention that the last time she went in to have the DPF reset they try to refuse to do it unless she paid for the thermostat to be fixed. There weren’t even any codes coming up to indicate there was a problem with the thermostat they just said that it might be sticking and it probably need to be replaced. She also recently used one of those are DPF cleaners and it didn’t do anything. She does mostly highway driving. Between the turbo and manual transmission, speed is not a problem for her to activate the regeneration.

Where would we find the emissions warranty documentation? Is there someplace online that you can go to enter your car information or generic blanket information about coverage? The car was purchased through Carvana Out of state and didn’t come with anything.

Look here. Print it out and read it several times to become familiar with what is covered and for how long. Keep the copy in the car so you can educate the service rep if need be.

https://www.vwdiesellookup.com/pdf/VWCourtSettlement_Emissions_Disclosure_Gen1_Automatic_Final.pdf

How many miles does she drive per trip? I drive 32 miles per trip (64 miles a day) I have a 13 beetle tdi with dsg Transmission. you could get a scangauge II for it, then program it to check egt / dpf temperatures also coolant temperature (there are instructions in the passat forum on the scangauge II thread). Mine hits 1100*F plus during a regeneration. Coolant temp is usually 188-192*F for coolant temp up to 197*F during a regeneration.