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Guest Message by DevFuse

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To Synthetic or not to synthetic that is the question

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15 replies to this topic

#1 foresterturbomiatacamry


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Posted 03 October 2003 - 02:43 PM

I just purchaed a 2004 Forester Turbo, and mt question is should I run synthetic oil.

I drive 28 miles each way to and from work about half freeway miles half stop and go. I tend to "visit" the red line about 4-6 times a day with the manual trans. I have been told its "good" to run synthetic oil on a smaller harder working engine.

I have a 2000 Miata with 24k and have ben running synthetic oil in with no problems as of yet but I guess it better not at 24 k miles.

Any thoughts for a first time Subaru owner would be appreciated.


2004 Subaru Forester Turbo
2000 Miata Miata SE
1995 Toyota Camry LE

#2 Chip


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Posted 03 October 2003 - 02:52 PM

DON'T use synthetic oil until your motor is completely broken in or else your rings won't seat properly.

I use Synthetic in my 89 OB only in the winter. When it hits -30° around here, regular oil turns to molasses. The synthetic stuff stays closer to it's normal,(ambiant), viscosity and the motor cranks over MUCH easier.

Other than that I see no advantage.

#3 ocsike74


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Posted 03 October 2003 - 03:08 PM

I think that the synthetic oil gives the same viscosyty parameters like any other mineral oil but with the diferense that is prolonged the oilchange intervallum, and this sintetical oil will mantain the same parameters all the time of using instead of the mineral one wich in time goes to loose the initially parameters. What I suggest is to consult your dealer about what kind of oil he recommends for you and follow his instructions. But if you really want to use syntetic oil use it all the time because the tribotechnology tells that isn't wery fortunate to change from mineral to syntetic and then back to mineral. these goes to shorten your engines life.

#4 Nickshu


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Posted 03 October 2003 - 04:11 PM

Lubricates well in spite of being dirty....oil changes theoretically required less often.
More stable and resistant to thermal breakdown.

Dirt and particulate still accumulate at the same rate....so really going 5000-8000 between changes may not be the best idea, but better with synthetic than dino.
Seals that are close to springing leaks with dino oil will definitely leak with synthetic (head gaskets?)....not and issue in a new car.

Im sure others can give more info.


#5 wrxsubaru


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Posted 03 October 2003 - 05:41 PM

Running sythenthec in a turbo charged car is a very good idea. After you use boost(floor it and the turbo will kit in), your turbo will get hotter than noramal, and if you turn your car off soon after you boosted the oil thats on the turbo bearing can get cooked on the baering shorting the turbos life, and killing the oil. Sence sythetic will resist heat break down alot beater than mineral oil, it wont cook on the turbo bearing near as easy, promoting turbo life and oil life.

Like most other people said wait till the car is broken in before running sythenthetic.

All my parants cars, and my car use sythentic, no problems at all, including oil leaks, and none of the cars are young, varing from my SVX at 120,000 miles to my dads 90 legacy at 330,000 miles.

#6 LameRandomName


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Posted 03 October 2003 - 08:06 PM

Switch over at the 12 or 15 thousand mile oil change.

#7 reoff


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Posted 04 October 2003 - 06:56 AM

Synthetic is a VERY good idea in your turbo. Switch over at ~ 10k and change every 5K. Keep an eye on your oil level!!! With synthetic, pushing your engine hard is a little more likely to see slight oil consumption... this is not a real concern. The benefits FAR outweigh this.


#8 cookie


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Posted 05 October 2003 - 12:08 AM

I run it in my M series BMW and it is reccomended by BMW and Corvette for Hi po.
In some cases cars can run a much smaller oil cooler with synthetics.
I'm running Dino in my stock Forester as I don't think a 2.5 is stressing much more than the head gaskets putting out this little power.

#9 applegump


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Posted 05 October 2003 - 05:54 AM

Synthetic is always a good idea. I'd change it at around 10k and stick to it once changed. With synthetic there is no need to change more often than is recommended by the owners manual. I've seen tests where Mobil 1 lasted for over 20k miles but I wouldn't go that far.

#10 bratman2


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Posted 05 October 2003 - 08:37 AM

We switched my wife's 2003 Legacy at 3.5k, the first oil change. Have been using Mobile 1 off and on for over 25 years with no problems. Corvettes and Vipers come from the factory with Mobile 1 so I would think they break in. Glenn Taylor.

#11 applegump


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Posted 05 October 2003 - 08:46 AM

I've heard that Corvettes and Vipers get broken in at the factory and then get the Mobil 1 before leaving the factory.

#12 ibis315


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Posted 08 October 2003 - 01:11 PM


#13 Setright


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Posted 08 October 2003 - 05:40 PM

Engine break-in, if the honing is done right usually takes only the first few hundred revolutions. Over in seconds. A little more will occur within the next say 300 miles, but we are looking at details.

I say, replace the factory oil after 600miles/1000km - filter included! - and go straight for synthetic.

With a turbo Mobil 1 5W-50 or Castrol 10W-60 would probably keep the consumption down and lubrication up at high revs.

Synthetic IS better by far, but perhaps not all cars need the extra proctection or cold start reliability. And cost....

#14 sprintman


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Posted 08 October 2003 - 11:04 PM

Turbo bearings like a syn (group IV or V, not III) to prevent coking. Get some miles on it with dino before changing. And most importantly use a 3oz maintenance dose of Auto-Rx with the syn. I can't disclose the reasons yet as under secrecy obligation so you'll have to trust me on this one.

#15 LameRandomName


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Posted 10 October 2003 - 07:22 PM

Originally posted by Setright
Engine break-in, if the honing is done right usually takes only the first few hundred revolutions.

That used to be true but modern engines have tighter tolerances and a different hone pattern.

When I built my harley, which used old fashioned iron jugs and old style rings, with a manual hone pattern, the break-in was done in 500 miles.

In modern engines the breakin takes 7500 miles or even more.

#16 BlueSoob


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Posted 10 October 2003 - 10:20 PM

I will have to play the engine break in theory here. After purchasing a 2003 Forester (non-turbo of course), I CHANGED THE OIL EARLY (Check the owners manual - 3000 miles) I don't care if they said 7500 at the dealership (they lied! to me... but knowing better, I followed my instincts and changed it.) Then at my 12k I switched to Synth. Get the little blue guy off to a good start. Grow up healthy and strong. :-p I have been doing the 5000 intervals after that. Choose to ignore the 7500 intervals and go 3-5000 miles :)

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