running synthetic at high mileage good or bad?
 

i've been hearing both that synthetic is good for high mileage engine and bad at the same time. I was wondering what everyone else views are

Re: running synthetic at high mileage good or bad?
 

Personally it depends on the condition of the rest of the car, if the care is in generaly good shape and I plan on keeping it for a while, I put in synthetic, mostly for its cold flow properties (quick lubrication on the sub zero (down to -40) starts). Some people clain that it starts or worsens seal leaks, but I have not had a high milage (300,000Km or 186,000mi) car that does not leak from somewhere :) I just put synthetic in my low (for me only 136,000mi :D ) milage SVX. just my $0.02

Re: running synthetic at high mileage good or bad?
 

You have a couple of options. You can use High Mileage synthetic oils from Mobil 1 or Valvoline. They will condition your seals to minimize the leaks. I would start with 10W30 to keep the seapage low while the seal conditioner does its thing and then move to 5W30.

Re: running synthetic at high mileage good or bad?
 

I remember reading a thread on here long ago that stated somewhere in the owners manual to never use 5w30, ever? for whatever reason. I don't have the owners manual to verify.

Re: running synthetic at high mileage good or bad?
 

My SVX is at ~198,000mi.
After I had the leaky gaskets replaced, I switched it over to mobil1 synthetic.
I don't like having to get my oil changed every 3000mi, so my choice is a matter of laziness.

Last year I changed the oil in September. Then in October I parked her for the winter.
So come May when I brought her out her winter slumber, it was 6months later and time to dump the oil and replace it, with less than 1000mi on the oil...
Which does kind of tick me off, at $85 an oil change it does seem like a waste..

I only drive the SVX in the summer (may-october), and then I usually only drive her on the weekends. I don't even think I do 7500mi a year in the SVX...
But every time I walk out of a store and look in the parking lot and she is sitting there, I think to myself, god I love my car, she is so sexy!
She just stands out, looks like nothing else in the lot, and I love that.
Downside of that is when I'm in the 2011 legacy, and I have to wander the lot trying to find it mixed in with all the toyota camrys...

Re: running synthetic at high mileage good or bad?
 

I do not have an owner's manual, but the service manual has a chart that shows 5 W 30 as ok as long as the ambient temp is < 32 F.

Re: running synthetic at high mileage good or bad?
 

Actually, I thought the chart said that the only oil suggested below 32F is 5w30. I will go out and check later. I also remember people saying that 5W30 was preferred in the summer because of the tight bearing passages. I hate when opinions conflict like this.

Re: running synthetic at high mileage good or bad?
 

Never? Actually, in my 1996 Owner's Manual, it showed 5W30 as "preferred" for the SVX over a wider range of temperature extremes. 10W-30 and 10W 40 were listed as well.

Pg. 9-9 of the 1996 Owner's Manual.

http://www.subaru-svx.net/forum/atta...1&d=1312124583

I personally use Mobil1 10W-30 exclusively in my new engine.

The 5W-30 can't be too bad. In my 1993 ZR-1, there was an emblem under the hood stating that the car used Mobil1 5W-30 as the "factory fill" and the recommended oil. That emblem currently resides on the radiator support of my Polo.

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Re: running synthetic at high mileage good or bad?
 

Cool, now I don't need to check my manual. I was suprised to see the 5W30 bar extend all the way up to 40C. That's 104F. That makes me feel better about running 5W30 year round in my area. Plus, if you go with high mileage M1, it is made a little thicker than standard 5W30 so it can probably extend beyond 40C without getting too thin.