I gotta do my due diligence and source this but I think there was a podcast called the "truth and justice podcast" that found a interview with the head of police before Jays testimony that said the police had located the vehicle and were withholding the location from the public at the time.
This means the police already knew about the whereabouts of Hae's car before Jay. This part gets slightly more conspiratorial but the police could have lead Jay to the car instead of the opposite.
Agreed, it's possible. Though we'd also need to explain why Jay is still sticking to a made-up "I buried a murdered woman" story decades later. And find the "real killer" who happened to murder Hae the same day Adnan loaned Jay his car and phone...
(PS: You can bypass the paywall to read parts 2 and 3 of Jay's interview by disabling Javascript.)
How Jay came to know where the car was parked is indeed confusing -- because it's hard to believe how the cops could know about it before him, which would presumably be a prerequisite for the cops conspiring with Jay to frame Adnan.
But according to the state's motion to vacate[0], the car was parked near the home of one of the current alternate suspects, i.e. one of the suspects whose existence the cops and district attorney for unknown reasons, illegally withheld from the defense. So I can't explain why Jay would know where Hae's car was parked, but that mystery is ultimately superseded by the mystery of the police's handling of the alternate suspects.
He discusses some inconsistencies here: https://theintercept.com/2014/12/29/exclusive-interview-jay-...
Edit: A Reddit comment claims to identify more inconsistencies in the interview: https://www.reddit.com/r/serialpodcast/comments/2xytci/comme...