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Synthetic in a new engine, bad idea?


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Hello,

 

I searched the archives and got mixed opinions about running full synthetic Mobil 1 in a newer engine. I have a 03 Outback and it has 5556 miles on it.

 

I changed over today and put 5W30 Mobil 1 the newer engine formula. Was I not supposed to switch this early?

 

And also someone mentioned that once you go synthetic you can't switch back, is that true?

 

Thanks for any information.

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I wouldn't worry about it. I think you've run enough miles to let the initial break-in to take place.

 

I did the same as you at 5000 miles and switched to Mobil 1. I now have 24000 miles on it and have no weird oil consumption issues. I didn't reinvent the wheel either before deciding to go to Mobil 1 at the 5000 mile mark. The owners manual said nothing to the contrary...I called my dealer and they said it was okay (they run synthetics in customer cars on request all the time at the first 3000 mile oil change mark). I called a reputable Subaru mechanic in the area and he said it was fine. Of course, I am sure there are other opinions on this. Also, there are many new cars that come with Mobil 1 as a factory fill.

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Just don't change brands of oil. Different Brands use different detergents. When you switch the brand the new detergents can strip the coating on the seals and you can get oil leaks until the new brand can build back up. I personally wouldn't switch back and forth between synth. and dyno though either.

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They have numerous advantages the first of which is better flow for equivalent viscosity at low temperatures. That's verified and that's important during the winter in Montreal.

The other one is better resilience to high temp (does'nt break down as easily under high load and high temp). That also seems to be a fact. I'm not sure the way I drive my car makes this so important for me though.

I've also heard that synth gives better lubrication. The fact tha people are weary of using it during engine breaking in period is a sign this is widely beleived (is it true?)

Finaly I've also heard (true?) that it sticks more to moving parts and thus lessen the initial wear an engine goes thru when first starting in the morning.

Amen.

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Switching back: Is NOT a fable.

 

What has happened is that new synth oils are formulated differently than 5 years ago.

 

5 years ago, switching back to dino oil would cause seal leakage, I can personally attest.

 

Newer oils, 'tis ok to go back and forth, but personally, after shrinking the 3 front seals on an otherwise flawless 1.8, I'll stick with just one.

 

Mike

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Frag, I don't disagree with your point that synthetic oils are superior to petroleum based oils. My point is, since petroleum based oils do an adequate job lubricating and cooling an engine (or other drive train components) for upwards of 200,000 miles, why pay 8x as much for a 'superior' product that will extend the life of your components far longer than the body/chassis will live. How many of us drive cars more than 200,000 miles? Additionally, if you do the math (in 200,000 miles you'll do about 67 oil changes; 335 quarts of oil) at a buck per quart, you'll spend $335 on petroleum based oil; at eight-bucks a quart, you'll spend $2,680 on synthetic oil. It doesn't make economic sense to me.

 

Incidently, I'm not anti-synthetic lubricants. I'm the fleet manager for a county in Oregon that operates more than 1000 equipment units (turf mowers - D8 Cats). We conduct ongoing tests (espcially in construction equipment) to evaluate the cost-effictiveness of (among other things) synthetic lubicants. With very few exceptions (Ford automatic transmissions being one), the OEM factory recommended lubricants have proven to be the most cost effective. That said, I do use synthetic oils in winch cases, large planetary gear-sets, and other select very-expensive, or critical to public safety equipment units.

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Philip and Moose, you're almost certainly right.

I think there's an unrationnal feeling of security in knowing your engine is bathing in the best oil you can afford.

For the time being that feeling is stronger for me, and others probably, than cold reason.

Would very cold climate qualify as a reasonnable reason to use synth? :confused:

 

P.S. the money argument might probably bring me back to reason sooner than later;)

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the viscosity of an oil is the same if the number is the same, dosn't mater if conventional or syn, and 8X more expenseive, are you serious, do you get a back massage and a gold container, maybe 2x, but concidering the added benifits, its certainly worth it, and going 200,000 miles seems to be the minimum on this board.

syn oils are better, if an oil barely passes the SL classification its an SL oil, if it greatly surpasses the classification its an SL oil.

the starburst oil classification requires the oil to pass a high shear test at 302 degrees, the engine oil never gets that high.

the reason that syn oils got a bad rap is because of the same reasons that multi vis got a bad rap in the 60's, they are much better now and on a new car worth every penny.

 

The reason that older engines seem to leak though with the syn oil is that the particles in syn are all the same size, like a marble through a funnel, but the dino oil is all different sizes,marble, ping pong and tennis ball, by comparison, the rubber interaction with seals is not an issue anymore.

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Quite few years ago, Consumer Reports did a study on engine oils (if I remember correctly, this was about conventional oils, not synthetic).

 

Amongst other things, they reported two key findings:

 

1. Provided the oil had the correct API designation, then was no significant difference between 'Brand X' and the more expensive brand names.

 

2. That all multigrade oils lost their mutigrade properties in time; and that the wider apart the two numbers, then the faster the multigrade properties were lost; i.e. a 5W40 oil will lose it properties faster than will a 10W30 oil.

 

Since reading that report (I think that it was probably 20 years ago), I have always bought the cheapest oil that I could find, and changed the oil and filter frequently (every 3000 km). I have never had any oil-related engine problems.

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"Syn vs. Dino" the bringer of many a heated debate :D

 

 

I like to run my EJ22 up to the redline, regularly. At the same time I like to leave oil changes til I pass 6k miles. Although I do perform all the proper maintenance at reduced intervals, I would like for my oil to be able to withstand an engine overheat situation without cooking and seizing my pistons. Danish winter mornings offer temperatures of about -15 degrees Centigrade.

 

Mobil 1 0w-40 does the business.

 

(5W-50 in summer)

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I can also attest that synthetic oil (i run mobil 1 10w-30 year round) does MUCH better in cold climates. Daily use during the winter for my car is starting up at temps ranging from -10 to 40 degrees, then running up to 4500 rpm on a regular basis. With synthetic, it starts easier, and I feel safer running it hard because I know that there is excellent oil in there. I also offroad my car a lot and tow with it, and after switching to synthetic oil, i've noticed a lot less "stuff" in the used oil, and the engine definitely makes less noise.

 

Farther north, EVERYBODY runs synthetic oil because it gets down to -40. If they ran dino oil, they would either have to leave their cars running all the time, or have a serious starter to crank it over. Not to mention the added wear caused by running dino oil in that situation.

 

It all really boils down to this in my opinion: For normal use, dino oil is just fine. But for extreme situations like racing or cold climates, synthetic really is much better.

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Hi All,

 

My ace mechanic in Idaho has a standard answer: Subies just don't like additives. But, hey - he's been a Subie guy since the dawn of time. I'm the second owner of my '96 Legacy - and He cautioned me against the synthetic oil in older engine. Something to do with seals. Anyhoo, not much help, I know, but just another opinion.

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  • 3 months later...

I recently developed leaks in all four of my spark plug seals. My car only has 100k km on it. I did switch to Mobil1 after using Walmart synthetic. A bottle of seal lubricant seams to have cured the problem.

 

My Forester gets the garage treatment now, probably will rust from inside out now :( , but when I had my civic with no garage I can tell you that synthetic helped dramatically with cold starts. Minus 35 Celsius without windchill, a norm in Toronto, 'cept for last year. That civic has 400k km on it and engine still has no oil burn! This is with 12k interval changes as well.

 

My other car was running dyno juice at same time and boy did it smell funny after cranking for what seemed like eternity on the same -35Celsius day.

 

My dilema?? Did synthetics cause my seal problem? Or was it because I changed brands (detergents different) as posted earlier? I would really like to keep running synthetics.

 

Hopefully we could get an answer directly from Subaru Canada?

Anyone know if/how we could do that?

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Originally posted by Zaphod

I changed over today and put 5W30 Mobil 1 the newer engine formula.

 

You're doing everything good. The only thing is that many have commented on the M1 5W-30 & 10W-30 being kinda noisey in Sube motors.

 

My 2.5 made a slight rod noise in the summer using M1 10W-30, even with only 10K miles on it. Substituting in 1 qt. of 15W-50 quelled it.

 

Visit bobistheoilguy forum for some of the best oil disscussion you'll find anywhere.

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