B737-800
Flight Crew Instrument; Flight Crew Air Transport Pilot (ATP); Flight Crew Multiengine
Flight Crew Last 90 Days 83; Flight Crew Type 1753
Troubleshooting
Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural Clearance; Deviation / Discrepancy - Procedural Published Material / Policy
Air Traffic Control Provided Assistance; Flight Crew Overcame Equipment Problem; Flight Crew Landed As Precaution; Flight Crew Requested ATC Assistance / Clarification; Flight Crew Returned To Departure Airport; General Flight Cancelled / Delayed; General Maintenance Action
Aircraft
While operating Aircraft X ZZZ-ZZZ1; at approximately FL310; and approximately 50 miles NW of ZZZZZ intersection; we notice a slight flicker from the master caution light that immediately extinguished. A few minutes later the light illuminated again. At this point we were able to determine it was the OVHT/DET indication on the recall pad. Indication remained for only a few seconds then extinguished again. All engine indications were normal. A short time later the engine fire warning system illuminated along with the fire warning bell. The number one engine light was illuminated. This indication only lasted for about 2 seconds then extinguished. Again; all engine indications appeared normal. I directed the First Officer to fly the airplane and communicated with ATC while I reviewed the engine fire checklist. At this point however; all indications were normal. Considering all factors; including destination; night time; sporadic and intermittent nature of the warnings; I elected to return to ZZZ after conferring with my First Officer. We elected to accept an overweight landing rather than risk the warning returning during a hold while trying to burn fuel. After reviewing the overweight landing procedure we elected to [request priority handling] and return to ZZZ. Approach and arrival was fully briefed; Flight Attendants were advised of the situation; as well as passengers. I elected to perform the landing as my First Officer was on his second day of IOE. I then took control of the aircraft and landed on Runway XXR. Landing weight was approximately 154;000 lbs; and landing was very soft. After turning off runway we stopped and had crash fire/rescue visually confirm there were no fire indications either with brakes or engines. We then proceed to the gate and deplaned normally. All defects were submitted via ACARS ELB.
Captain reported receiving engine overheat and fire warning system indications which resulted in return to departure airport.