John Lawton, 62, from Alsager, was last seen in an off-road race near Kalamata, in southern Greece in April.
Nine people from Cheshire Search and Rescue returned for a second time to the country on Friday.
The team said they covered a vast area of "unforgiving terrain" on Saturday, in temperatures of up to 44C.
A spokesperson said the search included olive groves and river beds around Aghia Sofia.
The six-day search has been funded thanks to an  
          online campaign
, which has now raised more than Â£16,500.
During the last hunt in May, rescuers found discarded energy gel packs which DNA analysis later showed had been used by Mr Lawton.
A spokesperson said the team members "remain positive" and are doing everything they can to find him.
Volunteers searching for a missing runner in Greece have said they remain "positive" despite a second attempt to find him so far proving unsuccessful.