I'm much more inclined to believe you guys. Sure my mechanic knows a lot, but his inspection was very minimal, and his knowledge is general. You guys know Saturns. I'm southern Minnesota--Faribault, more precisely. I'd love to get an opinion from an experienced member. Thanks for all the assistance. Since the cars runs so well, I'm gonna Grandma it the best I can. I only drive in town, so I should be good. The car does run and feel new--it really does! I drive new company cars all day and mine is quite a step up from them. Mine just sounds awful, that's all. Thanks again.

 

Get yourself a can of Seafoam and add it to your crankcase. Drive it for about 100 miles or so with that in the crankcase and then drain it and change your oil and filter. I'd go with a 10W-30 weight and see if the sound goes away. Broken piston skirt! Now I think I HAVE hear everything.

 

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I only drive in town, so I should be good. The car does run and feel new--it really does! I drive new company cars all day and mine is quite a step up from them. Mine just sounds awful, that's all. Thanks again.
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There is a point being missed here.
You have a sound you do not know what it is.
Sounds that sound awful
can mean something is wrong that can be fixed.
They are a symptom of something not right
The cosmetic condition of the car has no bearing on how mechanically correct something is, although generally it is a good indicator that proper care was taken of the car.
And what most people forget, it is cosmetics that sell when it is time to get some one to buy one.
However how pretty it is has little bearing on what ever is causing that sound.
A halfway decent basic mechanic can listen to the sound and determine most of the time whether it is critical or not.
Critical means it could turn the engine into a basket case the next time you start it or not critical can mean you have hundreds of thousands of trouble free but noisy miles ahead of you.
Where you drive the car is not related to what is wrong with it or the probability of having it towed home.
You don't know what the sound is and the two or three diagnostics you have typed in here don't even relate to each other.
You to find some one who will take an hour or so to determine what is making that sound and why!
And you need an explanation as to why, and if you don't understand what is being told to you, it would not hurt to say I don't understand can you be more specific.
The last time I was told what was wrong with my car just after I had replaced everything in the front suspension and it all needed replaced again the Yahoo who gave me the story expected big bucks. What he got was instructions to place the car on the ground I was driving it out. It and my 5 other cars would not be back.
The service manager was not happy to hear that in front of other customers standing in line to get their cars not repaired for big bucks either.

I don't know why you are getting completely different stories from different places but when stories don't jive, something is wrong with the picture.

I would not assume that just because the car looks nice it is a good idea to drive it around just in town until you get a proper story on what is wrong with it.
Some noises that are hard to describe in a forum like this are noised caused by something out of adjustment or a poor fuel mixture and are called pinging or spark knock. They can occur just as you described it. They are not of them self a major problem although they can be. I have blown up two engines by not dealing with the root cause of them.

Also noises that can occur just as you are describe them can be the engine trying very hard to blow up and are mechanical and un-fixable except for big bucks.

The things you are talking about in general have additional tests that can be run to help identify the reasons for them.
Either you have to learn how to do that your self or find some one that will actually take the time to do them for you.
As WHY when some one gives you a story.
If they are unable to either answer that question or their answer does not make sense and appropriate response is goodby.
I don't know what to say to help you.
Other than, you are not getting the right information to make a decision from, at least from what you say you are getting.

 

When I changed the oil, I put Seafoam in. It hasn't really helped with my problem, and I've put about 80 miles on the car. Should I get synthetic or conventional 10w-30? Brand preferences? I did notice some oil on one of my spark plugs today. It's the cylinder closest to the serpentine belt.

 

If you've got oil on a plug, then it could be a leaking valve seal or bad rings on that cylinder. As far as oil preference goes, I run Mobil One synthetic with a Mobil One filter on my Equinox. 10,000 miles between changes. I run 10w-30 in it. It's got 105,000 miles on it so I don't care that the factory calls for 0w-20. I run Castrol High Mileage in my Grand Caravan with a Purolator Gold filter. I have 192,000 miles on it. Both run great. I don't like Quaker State or Pennzoil for personal reasons, but am sure there are folks here that love one or both of them. Personal choice!

 

I put Mobil 1 0w-30 in last week because it said it worked with 5w-30 and 10w-30 cars. I've been using Bosch oil filters since Walmart started stocking them because they offer the best capacity. So Mobil 1 10w-30 is my best bet? Should I add anything else with it?

 

At this point in time brand, and synthetic vs dinosaur oil is personal preference. And personally I do not see any particular advantage of one over the other I use both for different reasons.
However
0w-30 was wrong by any criteria as far as I am concerned.
Where you are with that car, 10w30 or 20-w30 or 10-w-40 are all good choices. Oil filters are all good choices synthetic or dinosaur is in my opinion and I don't care and unless the car was new I would not use synthetics, but that is my choice.
Find a mechanic that can tell you what is wrong with it because oil on the spark plug and a noise are symptoms of not good. And continuing driving it and motor fix it in a can is not going to help you.