Should you change the thermostat, radiator, starter, alternator, or suspension parts as part of maintenance if they still work fine?
I have a 2004 Mercury Grand Marquis and I bought it 7 months ago. I did as much maintenance as I could so far and did all the stuff I needed to. Brakes, spark plugs, oil, tires, a small leak, new belt, fuel filter, power steering hoses, several gaskets, A/C compressor, battery, air filter, wipers, door lock button, etc. and now everything is in good working order with no pending issues and no CEL.
I have no clue when or if the last owners ever did the thermostat, radiator, alternator, starter, or any suspension parts, and I’m always a little paranoid that they could give out at any time at the worst moment. My mechanics said I shouldn’t worry about them because they are working perfectly fine. What do you all think? It has 101,300 miles.
Did you change the transmission fluid and filter? How about a chassis and drive shaft lube. If it ain't broke, don't fix it. Have you cleaned the MAF sensor and replaced the PCV valve?
I have not changed the transmission fluid. I saw in Scotty's videos that if you're unsure if it's ever been changed, especially at 100K in, then you should probably leave it be because it may slip afterwards if you do change it.
when did Scotty say 100k?
No
Thermostat, no signs of overheating, or under heating, just keep it until necessary.
Radiator, no leaks, still working, leave it be until necessary.
Starter, wait for it to wear out.
Alternator, just wait for it too. Who knows, it could go for longer.
Suspension, only if they is significant wear and tear, or the struts have gone bad. You’ll know. You’ll feel it.
Great. Thanks for your comment, I guess I'll leave them be for the time being. The suspension sometimes squeaks a bit when I go over certain rough roads with potholes but it's hardly noticeable, and the shop said that all suspension components look good, so I don't bother with that for now.
You're just wasting money if you replace a radiator when it has nothing wrong with it. I'm pretty sure the radiator in my 1979 Pontiac is the original unit, for example, and it's 43 years old. I replaced the original radiator cap after I noticed it was slowly losing coolant with no detectable leaks. It fixed the problem.
There's no real set "point" on when to change alternators, starters and suspension components. Alternators may go at 50k if you never drive and the trips are short, or it could last 200k+ if you drive cross country. Starters may go a long time as well, unless you use it a dozen times a day.
You might consider replacing a thermostat if you're doing a coolant change, but if your current one isn't giving you any problems, then don't sweat it.
Shocks and struts are a condition, not mileage thing as well. If you drive on roads that have potholes like the moon has craters, you might consider replacing them. As @Kaizen said, you'll know it when you have bad shocks and struts. If your shocks and struts aren't leaking oil, and they stop bounces within 1 or 2 cycles, they're fine.
Very helpful, thanks Justin.
Perhaps this post by @MountainManJoe will help you decide if you should change the transmission fluid.
https://carkiller.com/scottykilmer/qa/atf/
Did you change/flush the coolant?
Yes. I changed and flushed the coolant, the brake fluid, the power steering fluid, the oil, and also filled the washer fluid. Also did the differential fluid. Only one I have not done is the transmission fluid because I don't want it to slip and I'm not sure if it's ever been changed.
When you changed the coolant, did you properly burp the air out of the system?
I had it done at a shop, along with all of the other work. So I am assuming they did since they are pretty highly rated and have always done good work.
Never assume anything except that all firearms are loaded. Confirm the work has been done by observation. Are all the zerk fittings on the vehicle wiped off and have fresh grease on them?
What zerk fittings in particular should I look at? I had to Google what a zerk fitting is, as I am not mechanically inclined whatsoever aside from some basic knowledge.
All of them. They are on the moving parts of the suspension and drive train.