This is new to me. I not sure if they can follow your working permit expired date to grant your car stay in Thailand that long or not. But confirm your car maximum stay is 30 days if you enter as tourist.
If you need to confirm about this, you may contact Thailand embassy for more information about this.
*Copy and paste from their website.
Royal Thai Embassy
Address : 206 Jalan Ampang 50450, Kuala Lumpur
Tel (60 - 3) 2145 - 8004, 2148 - 8222,
2148 8350, 2148-8420
Fax (60 - 3) 2148 - 6527, 2148 - 6615
**For consular enquiries,
please call between 15.00-17.00 hrs.
Just double check even my car still under bank loan I still can drive out of Malaysia right.