Rust: your enemy
I'll pick this old thread up again to give more info for those who've got rusty Intrepids.
Even if you have the skills and tools to do all the body work yourself, it isn't worth all the effort and money to restore a rusty, high-mileage Intrepid. And especially not worth having a body shop do the work. Unfortunately while these cars are roomy, handle well, and look good, they have low book value even in excellent no-rust condition in dry climates.
As many guy's cars on this site show, they CAN be good project cars (as a hobby) for just that reason if you start out with a rust-free or low-rust car, because there are still lots of Chrysler LH cars in junkyards where you can get parts cheap , and you can also still get new parts fairly cheap compared to many other cars. But again, this is a hobby where people WANT to spend a lot of time doing it, not just fixing up a used car with a few problems quickly to have some transportation.
For the latter purpose, you can sometimes find a low-rust used LH series car that has been owned by someone who really took care of it and changed all the fluids regularly -- such as a retired person with a low-mileage car who kept all their service receipts. However, the original transmissions on the 1st Generation Intrepids (1993-1997) had problems with leaking seals and other internal parts that can lead to expensive repairs. The 2.7L engine in base models on the 2nd Generation (1998-2004) could develop major problems with oil sludge in the engine if the oil wasn't changed every few thousand miles. These cars can be reliable if all the fluids are changed frequently. But obviously there are other used four-door sedans that you can buy cheap that have better overall reliability records, such as old Hondas and Accuras.
With a rusty car you can just drive it until there is a major expensive mechanical repair needed, and then sell it as a parts car or junk it. You can try to keep it from rusting more by spraying off the road salt from the body and underside regularly in winter. However, you need to have the underside inspected (see below) for it to be safe.
I've got a lot of home experience taking rust off old cars and doing body work. I learned it all from books and old muscle car restorer magazines like Car Craft, but you can also take a basic auto body class at a local college or vocational school.
The previous extensive reply was good too tell you what is involved in removing body rust. Unfortunately, once you start you will find that the rust may be more extensive than what you see. To remove it, it is a tedious process with a noisy heavy-duty grinder (takes experience to be safe) or using a rotating wire brush & abrasive wheels to get off all the loose rust. Then you may need to use rust remover chemicals (available at auto parts stores). This is because there may be deep pits remaining with rust in them that you can't remove without a lot of metal grinding. Most of these chemicals (except for a few expensive ones) are strongly acidic and so you have to wear gloves, eye protection (maybe a face shield) and cover your arms. You obviously need to cover the other areas of the car and wear a GOOD particle mask that seals well, and gloves. Your neighbors will not like the noise from the grinder. Not fun for most people .
Painting over repaired rusted areas can be tricky, because the automotive touch-up spray paints available through auto parts stores in the matching OEM colors are lacquer, and the paint on the car is enamel. Sometimes the lacquer will bubble the enamel and then you've got a mess. But if not, lacquer is by far the easiest paint to use because it dries fast and you can sand off dried drips. (You need to obviously use lacquer primer too.)
Small-area body painting with automotive enamel is do-able at home but you need to get the paint color matched and mixed at an auto paint store and buy a little jar/air-canister sprayer (with a few disposable air-canisters). It dries much slower and is less forgiving to mistakes than lacquer. A lot of paint types are too dangerous to spray at home so you would need to select a kind that is relatively safe. You'd need a good organic vapor canister mask to protect your lungs from damage and wear a hood and coveralls. (The paint store has cheap plastic coveralls with hoods.) You have to sand the body filler (Bondo and other brands) very smooth and apply the appropriate primer first (and sand again). You can't do this in a garage unless you cover EVERYTHING you don't want paint spray on, and have very good ventilation, and also use a couple of big fans. If you paint outside it has to be on a very still day and you will still get dust in the painted surface. Again all very tedious unless you enjoy this type of thing. I do, but most don't.
But here's the big thing. The rust on the body of the car is not your biggest worry. It is what is on the underside. This includes not only the unibody frame, but the suspension components. These are safety items. It is really impractical to try to remove the rust from all of this unless it is just thin surface rust. I've done it on cars with jack stands and it is a dirty, messy job. Once you do it, then you have to spray or brush paint everything to prevent it from just rusting again. This requires something like Rustoleum Rusty Metal Primer or Clean Metal Primer and then Regular Rustoleum or one of the specialty paints frame paints from Eastwood (eastwood.com).
However, any rust deeper than surface rust on the suspension parts and frame is going to weaken them. If a suspension part breaks it can cause loss of steering control and an accident. The unibody frame (or ladder frame on old cars) can also become weakened, and this is also very unsafe. I had one old car where I found a huge hole in the rear frame after grinding all the rust off. The only way to fix this is a lot of grinding and welding.
Trying to restore a severely rusted car is only worth the time and money it if it is a valuable classic. For this, a "frame off" restoration is often done since the frame has to be inspected and patch welded to be safe. Often even this is not practical because too much of the frame has been eaten away by rust. There are actually companies that fabricate whole new frames for classic cars. Everything salvageable off the old car is is than transferred to the new frame.
If the car is rusty underneath, the brake and fuel lines may also be deteriorated. This is dangerous also.
If you are going to keep driving it, I would have your mechanic check the suspension, brake, and fuel lines for an opinion on what can be done too keep it safe. If you get the all clear from him (or have the rusty parts replaced), then change the oil and filter, air filter, fuel filter, have the brake fluid flushed/changed, change the coolant, and change the transmission fluid and filter - if you haven't done all that recently. You can also siphon out the old power steering fluid from the small tank (about 8 ounces) with a turkey baster and fill it up with new power steering fluid to the line on the cap dip tube. Do this a few times over a few months until you've used up the whole quart bottle of power steering fluid. Make sure the tires are in decent shape and filled up, and you'll be ready to roll.
Then if something major goes out (like the transmission), I would recommend that you sell it as a "parts car" for the best offer, or you can sell it to a junkyard. If the tires are good, you can have a shop take them off for you to keep (or sell separately) and put some used ones on to sell it. You can also keep the rims if they are nice alloy ones in good shape and put on some cheap used steel ones from a junkyard. With scrap metal prices high and depending on your location, some junkyards will give you at least a couple hundred for it. I got $500 for an old Chevy recently from a junkyard, because it had good parts but a bad frame.
But before concluding that the transmission is bad, replace the transmission (EATX) relay and fuse in the plastic box under the hood, and have your mechanic replace the two speed sensors on the outside of transmission - fast easy job 1/2 hour job and about $25 each for the parts. Anything wrong with the transmission electronic system is going to cost at least $100 for a transmission shop to diagnose (locate good shops at atra.com). And internal transmission repairs will be much more expensive.
Last edited by pt500; 11-25-2011 at 11:23 AM.
Reason: Add info on used cars