The best way to be poor is to put 4000 into a bad car that has a 4000 value. Then drive it till the engine fails completely taking another 4000 loss. Then buying your new 40 grand car that cost you 48 grandA lot of engines drive off the lot using a quart every 1000 and the dealer will tell you thats "normal".
If there poor (not derogatory - I grew up dirt poor) I would fix the brakes and bearings, try some different oils, and drive it until it plugs a cat or something. Honesetly with the use there giving it they might get years on it. The way to become not poor is avoid car payments.
Just my $0.02 which was given for free and may be worth less than that.