I did the search already and just didnt get the info i was looking for.

I have a 92 legacy AWD , 5 spd.

Has 229k miles on all original drivetrain .

I just purchased it and would like to convert it to full synthetic fluids .

I.E. oil , gear oil, frt and rear diff, etc.

Anybody have any ill effects from doing this on there higher mileage subies?

Ive done this conversion on older water cooled VW's with no ill effects .

Maybe alittle more leakage in some instances but overall I have had no ill effects in most cases.

I did the search already and just didnt get the info i was looking for.

I have a 92 legacy AWD , 5 spd.

Has 229k miles on all original drivetrain .

I just purchased it and would like to convert it to full synthetic fluids .

I.E. oil , gear oil, frt and rear diff, etc.

Anybody have any ill effects from doing this on there higher mileage subies?

Ive done this conversion on older water cooled VW's with no ill effects .

Maybe alittle more leakage in some instances but overall I have had no ill effects in most cases.

I do this to all my subaru and I rarely own any with under 100k. Never had any issues at all. And this will add 1-2 mpg also.

Just don't use mobil 1 or any other non gl4 rated synthetic in the tranny unless you want crunchy shifting

You'll be fine.

 

Just be prepared to replace the cam and crank shaft seals, and maybe the rocker cover gaskets.

You'll be fine.

 

Just be prepared to replace the cam and crank shaft seals, and maybe the rocker cover gaskets.

 

Is this because of the thinner oil?

I want to use Penzoil syncromesh in the tranny.

Is gl4 gl5 compliant.

Or even Redline MT90.

at this mileage it's not worth it, because there's no benefits to see. the money and time switching and possible risk of increased oil loss gains you nothing.

 

knowing that you want to switch, here's what i recommend. if the car is new to you i would recommend driving it for at lesat one oil change before switching to synthetic so you know if it's already consuming or leaking any oil.

 

sounds like you're experienced enough to know, but be sure to change the first couple relatively quickly and keep an eye on the oil color. the synthetic may dirty quickly the first couple of changes.

The only time I had a problem with this type of thing was with a domestic vehicle. It was higher mileage (for a dodge) 126,000 something for miles.

 

We had recently acquired it, and I went right to the synthetic oil (actually HELPED the oil consumption problems) However..... unknown to me, the motor had a lot of "gunk" buildup from the previous owner, and the synth oil broke all that free.

 

Long story short.....all that loose junk clogged my oil pump, and I was replacing the motor 2 weeks later:mad:

 

(never had this problem with a sube though....so IDK)

Grossgary - good point on just changing the oil for standard oil for the 1st change.

I think I will do just that and then i can gauge the wear on the rings for blowby and what not.

The rest of the fluids will be changed to a full syn though.

at this mileage it's not worth it, because there's no benefits to see. the money and time switching and possible risk of increased oil loss gains you nothing.

 

knowing that you want to switch, here's what i recommend. if the car is new to you i would recommend driving it for at lesat one oil change before switching to synthetic so you know if it's already consuming or leaking any oil.

 

sounds like you're experienced enough to know, but be sure to change the first couple relatively quickly and keep an eye on the oil color. the synthetic may dirty quickly the first couple of changes.

Grossgary is right. At that mileage, there's no benefit.

 

Besides, the synthetic will just leak all over the place and you'll have to fill it up more often.

at this mileage it's not worth it, because there's no benefits to see. the money and time switching and possible risk of increased oil loss gains you nothing.

 

knowing that you want to switch, here's what i recommend. if the car is new to you i would recommend driving it for at lesat one oil change before switching to synthetic so you know if it's already consuming or leaking any oil.

 

sounds like you're experienced enough to know, but be sure to change the first couple relatively quickly and keep an eye on the oil color. the synthetic may dirty quickly the first couple of changes.

Why would you say no benefits? I have never had any seal issues with my change overs and I have done it to all 12 of my roos.

Longer change intervals, increased gas mileage, better cold start ups, etc.

I do agree about doing a dyno oil change first, see if it leaks or burns a lot then go from there.

Looks like we have a split descision on the matter.

Im gonna do it like this.........

1st oil change - goes to dino oil using Dello 15w40 (has alot of good detergents to help clean it out)

2nd change - if no leaks or burning , change to full synthetic Mobil1 5w30 extended service.

Is this because of the thinner oil?

I want to use Penzoil syncromesh in the tranny.

Is gl4 gl5 compliant.

Or even Redline MT90.

Remember the tranny/diff share the fluid. MT90 is not good for diffs.

The only good tranny syn fluids to use in a subaru tranny are

Redline 75W90NS or Castrol TAF-X/"Syntorq" (but this is not easy to find in the states)

 

I asked Redline about MT-90 and they told me this:

 

In your Subaru transaxle where the GL-5 gear lube is called for I

would recommend the 75W90NS, I would expect the shiftability to be

close to the MT-90. The NS fluids have no friction modifier so are

not to slippery for the synchros the problem with most GL-5 gear

oils. The 75W90 would be suitable for the rear differential.

 

Regards, Dave

Red Line Oil

Looks like we have a split descision on the matter.

Im gonna do it like this.........

1st oil change - goes to dino oil using Dello 15w40 (has alot of good detergents to help clean it out)

2nd change - if no leaks or burning , change to full synthetic Mobil1 5w30 extended service.

Why 5w30 and not 10w30?

Becasue thats what i run in my 03 Turbo beetle S .

makes it alot easier to just buy it by the case.

My 90 Legacy was swapped to Mobile 1 when I got it about 4 years ago.

It had about 170 K on it then. Its got 190K ( It sees winter use mainly)

on it now and I add no oil between changes ...though I change at 4-5K.

It doesn't leak and it does not use oil.

The bottom line is...if it leaks or uses oil now...it'll leak and use oil later.

I haven't had my 2000 OBS long enough to change oil in it yet, but it'll

get Mobile 1.

 

Richard

Why would you say no benefits?

.

i'm wrong. there are some benefits. personally, at 239,000 i wouldn't give it much thought, i'd expect the possibility of oil loss to be greater than the chance of reaping enormous windfall benefits. but best to check and he is going to do that as i suggested in my first post.

Longer change intervals, increased gas mileage, better cold start ups, etc.

i know they are *supposed to* get better, but i haven't seen it. i had no increase in gas mileage or better cold starts in my vehicles when switched to synthetics (including diffs and trans). that leaves longer change intervals as the deciding factor and that sounds good to me if it isn't using or loosing any oil.

Well, it may depend on how cold your machine gets... personally I never noticed any difference between cold starting with dino or syn oils when we lived in Northern VA, but the first winter after we moved to South Dakota (where nighttime temperatures regularly hovered around -30F), I could barely get the engines to turn over after an overnight cold soak outside when they had dino oils, but after I switched to synthetic based oils I had no trouble cranking them in the coldest of SoDak weather.

 

Thats when I became a believer in synthetics -- although I have to admit that now that both of our vehicles have well over 100K miles (and over 225K on the OBW), I've gone back to dino oil in the crankcases. Still use syn ATF, though.

Really I havent figured out which synthetic Im gonna use in the MT.

I was going to run some Seafoam thru the crankcase for 20 minutes before draining the oil.

But I figured I better not shock the engine.

Found some 10w30 Dello for the 1st change.

Usually I would use 15w40 dello but I will be up in the snowy elevations alot and wanted the thinner oil for the cold starts.

Valvoline Synpower in my manual gearbox. BEst of of many expensive and cheap oils I've tried.

 

Stops the 2nd to 3rd grind common in Sube 'boxes.

at 239,000 miles i would just stay with dino oil. The change to synthetic may cause probelms on older engines. Remember when they talk about switching from dino to syn, they are talking about cars with less then 100,000 miles on them.

 

nipper