Synthetic or Organic Oil in an Older Car?

Flyn

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I run synthetic in my Caddy. I ran it in my Cobra after the break in period.

I was discussing with Amy whether to switch to synthetic in her 2004 Hyundai Santa Fe that we recently picked up. What do you guys think about switching to synthetic in a car that has had organic for 120K miles?
 

DEEZUZ

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More than likely it'll develope leaks. And if you have leaks now they'll only get worse. It can also knock debris/sludge loose, so you gotta worry about that.

The higher milege oils I believe have less detergents in them
 

GLADIATOR

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In one of my past get rich quick schemes, I was an Amsoil dealer. They warned to not use synthetic in older cars because the synthetic oil would clean sludge off seals and gaskets and cause oil leakage that could only be fixed by replacing all seals and gaskets. I started using the cheap stuff at Blaine Farm and fleet because our minivan burns oil. $2 a quart.
 

Marko

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I would think synthetic oil would cause it to burn more oil too
 

Thirdgen89GTA

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If you got leaks forget it, or the engine burns oil forget it. Cost of keeping it topped off goes up and won't really extend the life of the engine and the damage is done.

If the engine doesn't leak or burn oil I see no worries. Switch to synthetic and enjoy longer service intervals and better protection on cold starts

If you want to feel better about not shocking the engine with a change do a 75/25 fill, 50/50 fill, 25/75 fill, and finally 100% synthetic. But in most cases I'd say thats extreme and not required.

The sludge will get picked up with the filter. And I doubt there is enough to even clog a filter. If you feel wary just change the filter a few times during the first synthetic fill and top if off with new synthetic to make up the difference that was lost with the filter change.

I really think any engine thats under 120,000 miles thats seen regular oil changes will be fine to switch.

Rotella T6 for the GTA, and the Ford Motorcraft 5w-50 for the RS, because warranty.
 

b4black

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The concern about seals leaking is very outdated. Seals are better now and new synthetic motor oil additive packages address this.

"High Mileage" oils are just slightly thicker to slow down leaks (past rings and gaskets). On my older engines, I just threw in a quart of thicker oil (4x 10w-30 and 1x 20w-50 for example).

With older engines, oil contamination is a concern - leaking internal gaskets and worn rings are more likely to allow coolant or fuel in the the oil. Extended oil change intervals of synthetic might not be a good thing on an older engine.
 

Stink Star Productions

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Funny thing about oil now is that every GM car sold now uses full synthetic oil (dexos 1 ver 2) and it meets GM 4718M standard so you can use it in corvette and other high performance cars but the morons still come in and pay $8qt for Mobil 1 because they were the factory fill in 1992......
 

OffshoreDrilling

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In one of my past get rich quick schemes, I was an Amsoil dealer. They warned to not use synthetic in older cars because the synthetic oil would clean sludge off seals and gaskets and cause oil leakage that could only be fixed by replacing all seals and gaskets. I started using the cheap stuff at Blaine Farm and fleet because our minivan burns oil. $2 a quart.

[MENTION=2196]ShadyNinja[/MENTION]??
 

RICH17

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Amsoil user here and 14k oil changes. :fy:
 

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