Kenworth T660: Used-Buy Risk, Repairs & What to Check

From the research record

• PRICE: - Kenworth T660 sleeper trucks on truckpaper.com are stated by the site's own summary banner to "range in price from as low as $9,000 to $180,000" (https://www.truckpaper.com/listings/for-sale/kenworth/t660/sleeper-trucks, fetched 2026-08-19). Individual per-listing prices were not exposed in the extracted page text, so this is an aggregate range o
• FAILURES: - CAVEAT — chassis not confirmed T660: an electrical/aftertreatment fault on a truck the video titles as a Kenworth T680 traces a blown fuse "under aftertreatment" to a chafed wiring harness feeding the DEF pump — "the harness going to the [DEF] pump was the cause of the problem." Replacing the harness and fuse resolved it, followed by a separate f
• REPAIR: - Injectors: ~$1,000 each (video transcript: https://www.youtube.com/watch?v=CrDuDh0DsbM @ 00:00:58). - ISX in-frame chassis overhaul kit, OEM-channel part number 4376175, contents itemized on camera: complete head gasket set (head, intake, exhaust, EGR gaskets, cam seals, liner seals), a complete lower-end bearing kit (rod, main, thrust bearings),
• LIFE: - Documented service life of 500,000+ miles achievable; fuel economy 7-10 MPG typical; base warranty 2yr/250,000mi, extended 5yr/500,000mi. https://www.cylinder-heads.com/cummins-isx/
• VIDEO (00:00:58 https://www.youtube.com/watch?v=CrDuDh0DsbM): "thing. And luckily for me, it's a relief valve cuz injectors are about $1,000 a"
• VIDEO (00:01:00 https://www.youtube.com/watch?v=CrDuDh0DsbM): "valve cuz injectors are about $1,000 a"
• VIDEO (00:01:00 https://www.youtube.com/watch?v=CrDuDh0DsbM): "valve cuz injectors are about $1,000 a piece. So, we're starting it. And uh"
• MARKET (soarr.com dealer inventory, 4 listings observed 2026-09-05): low $22,900 / median $31,950 / high $69,950. Agent-sourced dealer listings (2009-2014, 485k-889k mi): $22,900-$69,950, median ~$31,950.