WA state' heres a little INFO for YOU, 83Turbo..
OpenCarry.org - State Information For Washington
ONLY if you have a CCW can you have a LOADED handgun in your CAR' BUT a shotgun, a rifle, or similar, on a RACK, in the back window, will be FINE only if you have a PERMIT/LICENSE. just print the page out and find the specific law on line with regards to the state of Washington relating to open carry, and print it out, have some copies, one in the car, one on you if possible in your wallet, so you can show to the Law Enforcement Officer that it is LEGAL.
if this is simply to protect your car; not your person, you're very naive.....you NEED to get a COMPLETE appraisal of car (check into that on here, i think several members would be able to confirm) from a COMPETENT insurance company who KNOWS what EXACTLY you have, and how much in there (dont just go for overall value, go into the parts, market value of parts, labor, rarity of said parts depending on which parts, sources for said parts) and also if your parents, (if youre living with them) happen to have home owners insurance, then file the car's stuff and sh!t as personal property and see to it that you also have complete prints/copies of policies and such, keep a copy of the registration in the car, put your car title in a safe deposit box at the bank, or a safe at your home;as that will often help get your car back along with paperwork...
it also helps tremendously to put VIN #s on as many parts as possible permanently in order to be able to track down parts....this may sound wayyy overboard, but honestly, its safer than having a gun IN the car, and NOT on your person, and not having it when you need it, i mean come on. someone breaks into the car, hotwire it, or find the gun, steals the gun, use it in crime, they find the gun, serial is registered to YOU....say hello to Bubba unless you can CONCLUSIVELY prove that you were NOT the one using it....
another thing, you are EIGHTEEN, right? in WA, you CANNOT open-carry ANY firearms until 21....thats TWENTY-ONE...thats pretty much 2 and a half years from now.....I;'d do what other suggested, and park the "hooptie" and get a POS crap car, maybe a FWD X body (citation type lol) or the A-body car (Buick Century, Olds CIera, Pontiac 6000, Chevy Celebrity)...the Buick Century and the Oldsmobile CIera had the option of the LG3 FWD 3.8 v6 which is quite similar to the RWD SFI engines, so you;d at least be in keeping with buick v6s