I bought a high mileage (130K) used Saturn (98 SW2). I do not know the maintenance history of the car or if it has been kept to the maintenance schedule. What things should I avoid working on? For example, I have read that a regular flush of the trans. fluid is good UNLESS it has not been done regularly, which could foul things up in a hurry. I would like to avoid killing the car while trying to extend the life of it.
Because you are uncertain of the history of the car, you should take the view that nothing has been done yet.
A quick checklist is:
- Engine Oil & Filter
- Radiator fluid (also get one of the good cleaners that you leave in the car for ~200 miles, but be careful as the outside temperature cannot get below freezing while this cleaner is in your system).
- Timing belt/chain (due to the cost of replacing this, you can check the condition of the belt and if it is in good shape, you can skip it)
- Check the brake fluid, make sure it looks the proper color and has no foreign objects in it.
- Check the spark plugs, see if there is corrosion or if the plugs are damaged.
- Check the transmission fluid, see if there is foreign matter in it.
- Check the brake pads/drums for wear.
- Check tires for balance and any unusual wear.
- Check the fuel filter and get a high quality fuel system cleaner and put that in with a tankful of fuel.
- Check the A/C freon levels, add freon as necessary.
Depending on your mechanical level, you may take the car to a trusted mechanic and tell them the situation and they can go over the whole car and tune it up. It will be worth a few hundred dollars to find out if there is anything you need to be worried about before something breaks.
By the way, I have never heard that replacing the transmission fluid regularly is bad.
I recently picked up an old Mercedes. Previous owner said he'd switched out the fluids... that he'd been a mechanic for a number of years. Long story short, NEVER trust previous owners... particularly when it comes to fluids. They don't even have to be dishonest, they might just be incompetent or lazy.
Fouled oil carries a bunch of crap in it that will end up embedded in your crankshaft journals. Fluids are relatively cheap. Even if I'm not sure whether I can get a car I've purchased running (which I was able to with the Mercedes), I won't ever again run the engine of a car I purchase beyond the point of sale test without first swapping out ALL the fluids. You just never know what kind of crazy things previous owners have done (or not done).
See if a dealership can pull the service history for you. I'm under the impression that, say, a GM dealer can pull all the service records for a vehicle, even if the work was performed by another GM dealer. If that's true, you still won't have records of work performed by independent shops, but it's better than nothing.