The 17-stone man restrained Bernard Doherty as the thief attempted to steal a Mitsubishi Shogun outside his house in January last year, it was claimed.
Mr Machin, 53, used his knee to hold the 24-year-old to the ground while his cousin William Jones, whose car was targeted, lay across his legs.
An inquest at Hanley Town Hall heard the pair, both lorry drivers, held down Mr Doherty while they waited for police in the early hours of January 9 last year.
By the time police arrived at the address in Middleport, Stoke-on-Trent, Staffs, they found Mr Doherty, unconscious but still being restrained, the inquest was told.
The father-of-one, who was from Stockport but was in the town for a family funeral, was later pronounced dead at hospital.
A post-mortem found Mr Doherty, who had a partner, Brooke and a four-year-old daughter, Britney, died from asphyxia due to an object pressing on his chest area.
The cousins, who said they “showed no malice” towards him, were later arrested on suspicion of unlawful killing.