B737-800
Flight Crew Air Transport Pilot (ATP); Flight Crew Multiengine; Flight Crew Instrument
Situational Awareness
Aircraft Equipment Problem Less Severe; Flight Deck / Cabin / Aircraft Event Smoke / Fire / Fumes / Odor
General Flight Cancelled / Delayed
Aircraft
Fume/odor event at gate as indicated by oil fume odor probably related to APU bleed air. Pilots removed themselves from flying status. Aircraft removed from service. No passengers involved as problem was detected prior to boarding.
B737-800 Captain reported refusing aircraft due to fumes on board during preflight at gate.