115K....going to synthetic

[tnice17]

my 00LGT has 115K on it and i have been using castrol GTX high mileage for about 10K miles. i know i know i should stop using it and i am planning on it. i was thinking about switching to Mobil 1 fully synthetic. i searched and found that its pretty good. but i didnt find alot of info about if subys burn it easy, how the car runs after? do you think its worth it, going to synthetic after 115k on regular oil?

[Reason]

I'm wondering why you used high mileage on a 100k motor. Isn't that rated for 150-175k? Anyway I wouldn't go to thing first. So stay away Mobil 1 5/30. I like Royal Purple, may legacy was more quiet when running that. I would suggest 10/30 at first, but you shouldn't have problems.

[tnice17]

royal purple is expensive. like $10 a quart. what is wrong with mobil 1? any other good brands?

[Reason]

Sometimes it's good to pay a few $ more to protect a few thousand of these $$$.

[2.5GT]

i switch mine over to synthetic when i bought the car at 100k..using mobil 1 too and it leak like crazy. from the valve covers...

[Reason]

It's due to shitty valve cover seals.

[rougeben83]

I don't think it's worth it, especially on your motor...I just use regular castrol GTX and I beat on my car. I played around with different oils (Mobil 1 7500, full mobil 1 synth, motorcraft synth, etc) when I first got the Legacy and didn't notice a lick of difference in how the car ran...I just lost more oil with the synthetics.

Getting regular oil changes is more important IMO, but oils is one of those hot topics that people always seem to have an opinion on, so YMMV.

Most "high mileage" oils are rated for cars over 75k miles. All the change is the additive package w/ the regular dino oil.

[tnice17]

my valve cover gaskets are already leaking a little. i can see some drops wanting to form. if i replace those will i be good with synthetic? i really want the life of the motor to last. thats why i was thinking about synthetic. should i look more into synthetic or just screw it?

[Reason]

If you replace your valve cover gaskets you won't have to worry about them leaking. But how are the rest of your gaskets? Try it anyway, see what happens. Worse case you will have to change the oil to something thicker.

[tnice17]

what other gaskets should i look out for? do the head gaskets have a better chance of going?

[Reason]

Check to see if you have any oil leaking from the bottom of your timing cover and on the bottom where your engine and tranny meet.

[tnice17]

i was leaking a little oil from the bottom of tranny/engine. but for some odd reason it hasnt left any oil in about a month. nothing at the timing belt last time i checked.

[Reason]

When I switch to synthetic I used Castrol syn blend. Maybe try that first, then next oil change go full synthetic.

[tnice17]

whats the difference? between the blend and fully synthetic. should i stick to one brand, like castrol blend, then go to castrol fully synthetic?

[Reason]

a blend is part synthetic and half fossil. Don't worry about sticking with same brands, worry about getting the right stuff. The Castrol syn blend shouldnt be much iirc.

[tnice17]

if i go syn blend and i dont like it/leaks. can i go back to regular oil?

[Reason]

Yes

[tnice17]

perfect. thanks for all the quick info. i have to do an oil change in 50 miles so ill let you know how it goes.

[miatapaul]

Oil is really a subject that can evoke emotional responses. Check out Bob the oil guy's site. It is one of the best sites I have seen about oil. Personally I would use a cheap synthetic, such as super tech from Wal Mart and a good filter such as a Puralator Pure One. Though I think frequent changes are really more important than the actual oil you use. Over at Bob's they do a lot of oil analysis, but by the time you pay for that you could have just changed it. Perhaps if you have a whole fleet the oil analysis makes sense. Synthetic does tend to leak more than dino.

By the way I don't think the "high mileage" oil will hurt anything. I think the additives are really there to help the older seals stop leaking.

[rougeben83]

Oil is really a subject that can evoke emotional responses. Check out Bob the oil guy's site. It is one of the best sites I have seen about oil. Personally I would use a cheap synthetic, such as super tech from Wal Mart and a good filter such as a Puralator Pure One. Though I think frequent changes are really more important than the actual oil you use. Over at Bob's they do a lot of oil analysis, but by the time you pay for that you could have just changed it. Perhaps if you have a whole fleet the oil analysis makes sense. Synthetic does tend to leak more than dino.

By the way I don't think the "high mileage" oil will hurt anything. I think the additives are really there to help the older seals stop leaking.

Yup, the additives are really there to help compensate for bad seals, compression loss (slight) and keeping deposits down...they apparently work, but there's really nothing significantly different from the regular oil they base the formulation of off...More important thing is to use the right viscosity oil as per the manual.