Trapped and hurting from numerous fractures through his ageing body, a defiant Herbert Schutz survived four days in the elements by bunking down with his loyal kelpie, Boydy, to fight off the cold.

And even when help arrived, three freezing nights after Mr Schutz was first pinned by his own car on his remote property near Rylstone, in the central tablelands, Boydy would not leave his master's side until he was free.

Wonderdog: Boydy the kelpie stayed with his owner for four days.

Mr Schutz, 76, remained in a serious condition in John Hunter Hospital on Tuesday night after two neighbours found him under his crashed four-wheel-drive on Monday night.

He had been there since at least Friday, when he was able to escape from his wreck after it hit a tree only for it to roll and pin him.