Pile into the jalopy! (4)
I believe the answer is:
heap
I believe this is a double definition.
'pile' is the first definition.
(I know that pile can be written as heap)
'the jalopy' is the second definition.
(synonyms)
'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?)" .)