Documented failure points and real market prices for the Peterbilt 379, sourced and dated.
Confidence 0%7 observed comparables
As of Sep 5, 2026What can make the cheap machine expensive?
ISX15 injectors fail by sticking open or closed, a common spec option in Peterbilt 379 conventional trucks.
Cost not yet verifiedInjector copper sealing cups crack from heat cycling, leaking combustion gases past the injector seal.
Cost not yet verifiedPeterbilt 379s were heavily spec'd with Cat C15/C13/3406 engines; overheating these engines can crack heads or warp the block.
Cost not yet verifiedTurbo bearing damage on twin-turbo C15s is expensive to repair when warm-up procedures aren't followed.
Cost not yet verifiedCommon questions
How much does a used Peterbilt 379 cost?
Observed listings range roughly $39,995 to $79,950 depending on age, condition, and configuration (as of 2026-09-05).
What fails on the Peterbilt 379?
The most cited concerns in our evidence record: Fuel Injectors (Cummins ISX15, common Pete 379 spec), Injector cups and solenoids (Cummins ISX family), Cylinder head/block (legacy Caterpillar C15/C13, common Pete 379 spec). See the risk breakdown above for details and sources.
From the research record
- FAILURE (2026-09-05, agent-fetched, Claude spot-verified sample): Fuel Injectors (Cummins ISX15, common Pete 379 spec): "ISX15 fuel injectors fail in two ways: they stick open (causing white smoke and rough idle) or stick closed (causing misfires and power loss)." https://skylinerrepaircenter.com/blog/cummins-isx15-engine-problems-a-mechanic-s-perspective
- FAILURE (2026-09-05, agent-fetched, Claude spot-verified sample): Injector cups and solenoids (Cummins ISX family): "The copper cups that seal the injector to the cylinder head crack from heat cycling, allowing combustion gases to leak past." https://skylinerrepaircenter.com/blog/injector-problems-in-cummins-isx-engines-complete-guide
- FAILURE (2026-09-05, agent-fetched, Claude spot-verified sample): Cylinder head/block (legacy Caterpillar C15/C13, common Pete 379 spec): "Overheating a Cat C15 or C13 can crack cylinder heads or warp the block - repairs cost $15,000-$25,000." https://skylinerrepaircenter.com/blog/caterpillar-truck-engines-legacy-maintenance-guide
- FAILURE (2026-09-05, agent-fetched, Claude spot-verified sample): Turbocharger (legacy Caterpillar twin-turbo C15): "Turbo bearing damage costs $3,000-$5,000 to repair without proper warm-up procedures and maintenance." https://skylinerrepaircenter.com/blog/caterpillar-truck-engines-legacy-maintenance-guide
- MARKET (7 real exact-model listings, 2026-09-05): low $39,995 / median $55,900 / high $79,950. 7 of 13 real listed units shown as a representative spread (full inventory range $39,995-$79,950, 160k-2.86M miles).
Sources
- skylinerrepaircenter.com (failure evidence)repair-industry · verified · accessed 2026-09-05
- skylinerrepaircenter.com (failure evidence)repair-industry · verified · accessed 2026-09-05
- skylinerrepaircenter.com (failure evidence)repair-industry · verified · accessed 2026-09-05
- soarr.com dealer inventory (7 exact-model listings)dealer-inventory-aggregator · verified · accessed 2026-09-05