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.

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    Mechanics do use-car inspections all the time, for maybe $70-$100. They typically look for issues that will leave you stuck on the side of the road. It gives you a good starting point for doing DIY maintenance.
    – Jay Bazuzi
    Mar 9, 2011 at 5:44
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    @Jay, that is a good place to start but you need a mechanic you can trust. It would be all to easy to "find" an issue on an old, high mileage car Mar 9, 2011 at 13:36

3 Answers 3


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:

  1. Engine Oil & Filter
  2. 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).
  3. 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)
  4. Check the brake fluid, make sure it looks the proper color and has no foreign objects in it.
  5. Check the spark plugs, see if there is corrosion or if the plugs are damaged.
  6. Check the transmission fluid, see if there is foreign matter in it.
  7. Check the brake pads/drums for wear.
  8. Check tires for balance and any unusual wear.
  9. Check the fuel filter and get a high quality fuel system cleaner and put that in with a tankful of fuel.
  10. 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.

  • Thanks, this is a fantastic list. Also replacing the transmission fluid regularly isn't bad. It when it hasn't been replaced and then is flushed that it is bad. I have read that over time, foreign matter builds up. If it is still working, that matter is simply out of the way. When it is suddenly drained and filled, that matter moves and resettles in potentially troublesome spots. Mar 8, 2011 at 13:52
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    Consider doing the fuel system cleaner before doing the oil, as ring blow-by can lead to this cleaner getting into the oil. Probably not a big deal, but it's something I try to follow. I'd also consider adding water pump lubricant when re-filling the radiator. Mar 9, 2011 at 12:05
  • I would add power steering fluid to this. And for #2 "radiator fluid" (or engine coolant) I have read that you should not mix green and red antifreeze, although this is for my 1995 Toyota Land Cruiser - not sure how much this applies to other vehicles.
    – Tone
    Jun 19, 2011 at 1:47

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.

  • This is definitely true of Subaru: they can look up all dealer-performed service by VIN number.
    – Bob Cross
    May 30, 2012 at 14:41

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