Pile into the jalopy! (4)
I believe the answer is:
heap
This clue is a double definition.
'pile' is the first definition.
('heap' can be a synonym of 'pile')
'the jalopy' is the second definition.
('heap' can be a synonym of 'jalopy')
'into' acts as a link.
(Other definitions for heap that I've seen before include "Rough pile" , "car on its last legs" , "Amass" , "Mound, pile" , "Pile (of scrap?)" .)