T1N? Turbo resonator recall/repair/replace. Mileage is low for a diesel, should get another couple hundred thousand miles out of it, if it's been taken care of.
Almost too late to worry about it much, since you've already bought it?
2018 (2017 Sprinter Cab Chassis) Navion24V + 2016 Wrangler JKU (sold @ ????)
2016 Sunstar 26HE, V10, 3V, 6 Speed (sold @ 4600 miles)
2002 Roadtrek C190P (sold @ 315,000kms)