YACarT

trilks

Golden Member
Aug 16, 2002
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I am getting an oil change tomorrow, and just wondering, should I pay more for synthentic oil? I had always gotten conventional, but got synthetic last time, didn't notice a difference.

I have a '94 Geo Prizm with 122K miles, and have never had any engine trouble. However, I do live in Minneapolis and will have my car outside all winter :(, so it will be pretty hard on the car. Would synthetic make a difference? (would it not become as viscous in cold temps?)
 

RU482

Lifer
Apr 9, 2000
12,689
3
81
yes it will make a difference. On a car that old, you are likely to start seeing an oil spot on the driveway if you use synthetic. Tends to flow better through leak holes and old gaskets.

that, and it will be better for your cold starts in the winter
 

amdskip

Lifer
Jan 6, 2001
22,530
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If you are going to run synthetic, you need to change it over asap.

CrackRabbit, there are plenty of reasons to use synthetic but lets not make this a debate. Just do a search in off topic for synthetic.
 

Tea Bag

Golden Member
Sep 11, 2004
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NO.

It's a GEO. Stick to the Manufacturer requrements. Ususally, the only cars that require synthetic from the lot are cars that hi-rev or use a premium fuel setup (most luxury cars, turbocharged cars, ect.). You will see no performance or longevity benefits, plus it may have a negative effect if your car has been using conventional for 100K + miles.
 

trilks

Golden Member
Aug 16, 2002
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Originally posted by: CrackRabbit
Dino oil, for a car that old there is no reason to use synthetic.

I would have thought that would be a reason to use synthetic. I want it to run for as long as possible, and I don't mind spending a little bit more every 4-5K miles to keep the engine running smoothly.
 

PCTweaker5

Banned
Jun 5, 2003
2,810
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I started on synthetic on my ride after 166k miles and not a single leak or problem and I have run this baby pretty hardcore. I say go for it but I would make a quick check for leaks first as its possible that you may get more leaks but not really likely, thats kind of a myth.
 

trilks

Golden Member
Aug 16, 2002
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Originally posted by: PCTweaker5
I started on synthetic on my ride after 166k miles and not a single leak or problem and I have run this baby pretty hardcore. I say go for it but I would make a quick check for leaks first as its possible that you may get more leaks but not really likely, thats kind of a myth.

I have been running synthetic for about 4K miles, and haven't noticed any leaks. But then again, I park on the street, so its possible that I just don't see it, since I park in a different spot every time.
 

CrackRabbit

Lifer
Mar 30, 2001
16,642
62
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The reason i say there is no point is because most of the wear that is going to happen on the engine has already happened by 122k (at least half, it is a toyota motor), also as redly1 said it can cause your motor to leak because of the extra detergents in the oil. You are better off using a good 5w-30 with a mobil 1 or wix oil filter than spending the money on synthetic oil.
 

PCTweaker5

Banned
Jun 5, 2003
2,810
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Yeah as I am about to leave somewhere where I have parked I often check under the car to see if there is a wet spot under the hood or if there is any smoke coming from the engine when its running but nothing. Everything is perfect and runs smoothly. My car used to shake quite a bit when idling but now its very minimal. I just switched over to synthetic for this oil period so the next oil change which is about 300 miles away will be the second dose and should be even better since all of that old dino should be cleaned out but thats where leaks might arise but I think they would have showed up by now so Im not worried. Im changing every 3000 miles BTW because I floor it all the time and I want my engine to last at least 250k miles.