← Oil leak / consumption on all engines
Symptoms · 6.7 Cummins 2007-2018
6.7 Cummins 2007-2018: oil leak, oil consumption or rising oil level
2 documented failures on this engine list this among their signs. They are ordered from the most widespread down. Each one shows the signs in its record's own words, how to tell it from the others, the usual fix and any recall or bulletin.
Not sure which engine you have, or want the recalls for your exact truck? Check your VIN: it names the engine and lists the campaigns for that model year. Whether a recall is still open on your VIN: nhtsa.gov/recalls.
verified
How widespread: Common
12 NHTSA owner complaints match it, out of 1,355 checked
How it shows up
- fuel in the oil / rising oil level (pairs with the oil-dilution mode)
Its other signs
- audible 'chuff chuff' exhaust beat (compressed gas past an injector's copper seal)
- fuel smell, smoke, rough cylinder balance; balance-rate DTCs
How to tell it apart
- cylinder-balance / contribution test to locate the weak hole
- listen at the exhaust for the chuff beat; check oil level trend for dilution
- return-flow / leak-back test per injector where equipped
Usual fix
replace copper sealing washers (cheap) if the injector itself tests healthy
Recalls and bulletins
TSB 05175565A$TSB 18-002-14 REV. BTSB 18-002-14 REV. ATSB 18-002-14
Root cause, parts and sources →
aggregated
How widespread: Occasional
How it shows up
- oil level RISING between services (fuel accumulating)
Its other signs
- fuel smell on the dipstick; sheen
- diluted oil risk: bearing wear, reduced film strength; DPF-era trucks on city cycles worst
How to tell it apart
- track oil level between changes - a rising level on a diesel is fuel or coolant, never good
- sniff/sheen the dipstick; lab oil analysis (fuel %) for confirmation
- review regen frequency/aborts in the ECM; cross-check injector health
Usual fix
shorten oil-change intervals on city-cycle trucks; verify regens actually complete (duty cycle)
Root cause, parts and sources →
Other symptoms on the 6.7 Cummins 2007-2018
Hard start, long crank or no-startLoss of power, limp mode or derateWhite smoke from the exhaustLosing coolantOverheating or temperature creeping upTicking, knocking, rattle or whineMisfire, rough idle, hesitation or surgingDEF, DPF and regeneration warnings
Everything on the 6.7 Cummins 2007-2018Its recalls and bulletins