What is the best engine oil/trans fluid to use 2002 Legacy GT

Guys, my 2002 LGT Limited with 117k on her seems to like the oil..Headgaskets were done about 10k ago..What do you guys recommend to be the best engine oil to use? Is royal purple an option to possibly make her run a little smoother..she will be due for an oil change pretty soon..Also, is it just me or are the 5 speed manuals a little sluggish???What do you guys think is the best 5 speed gear oil? Thanks for your input....

Don't...... Just don't...

I use Castrol Syntac in both my cars and that's what I only use bottom line...I'm thinking about that new Castrol Edge though. I put only the best simply because that's what lubricates your engine and gears and what not, it's worth while. I just put Valvoline Synthetic Transmission fluid in too...SYNTHETIC

for the engine oil, 5w-30 is the standard "all temperature" oil. I use mobile one from Walmart - it is ridiculously cheap at about $22 for 5 quarts for great oil. We need 4.2 or something like that for our LGTs so after a couple of changes, its like you get a free oil change with all the left over oil. Plus, you can get away with 5k mile changes - just check the level from time to time to see if there is any burning.

 

I've been running 0w-30 recently with no problems - supposedly it is better for higher gas mileage but I don't have the numbers to prove that yet - I am logging my mileage pretty carefully so a few more hundred miles will do the trick.

 

I've read that synthetic oil tends to "swell" seals in the engine / oil pan etc. So switching back to regular will possibly cause leaks after using synthetic - no personal experience with this. Truthfully, frequency of oil change matters a heck of a lot more than synthetic / more expensive oil - every 3-5k with a good filter will keep your engine smooth. Not sure about Royal purple, but have seen some bad things about it on G35 forums.

 

For gear oil, you need a GL-5 rated oil. It is recommended that 75w-90 be used for the tranny and 80w-90 for the rear diff. It seems like the best subie oil is made by subaru (Non-synthetic) but it is hard to find and not all dealers have it or only sell it in larger quantities. Solbey seems like a decent subie mechanic who will sell in whatever quantity you need if you pay the guy a visit:

 

http://legacygt.com/forums/showthread.php?t=122679

 

I recently bought some Amsoil Severe Gear because it was available at about $10 a quart at a local shop. I just purchased 5 quarts - 3.6 for tranny and 1.5 for rear differential. It is rated to be pretty decent and seems to have quite a cult following. I hear Redline makes some good oil as well. Generally, gear oil is much more expensive than motor oil, but it lasts over longer replacement intervals, so i feel like it is better to splurge a bit.

 

Amsoil says that you don't need LSD additive for the diff when you use Amsoil severe gear, and even though the subie book does not recommend 75w-90 for the diff, Amsoil says it is fine, so I'll trust them with that. In addition, I did not want .5 quarts of gear oil left over in two different viscosities. If you really want Amsoil they sell through some kind of odd pyramid-scheme like network so you need to find a local dealer, most likely a backyard mechanic, who will sell it to you.

 

When changing the tranny fluid, especially if you haven't replaced it in a while, it is best to change the fluid TWICE. Once with cheaper 75w-90 to clean out the system, and another time with the good tranny oil.

 

Be careful when changing it, and beware of sludge:

 

http://legacygt.com/forums/showthread.php?t=124417

 

http://legacygt.com/forums/showthread.php?t=123942

 

http://legacygt.com/forums/showthread.php?t=124383

 

It may be easier for you to buy a fluid transfer pump ($7) so that you don't have to remove the airbox to get to the trannsmission fill hole. You will need this for your rear diff too.

rao... synthetic oil...

oh no, someone's calling in the synthetic oil thread police

Yeah that's a second on synthetic preference...wait i was the first but anyways. Drain your oil and run synthetic. It's better for the car in the end and it allows you to change oil every 7500 miles or so with regular oil you should change it every 2-3k.

and it allows you to change oil every 7500 miles or so with regular oil you should change it every 2-3k.

 

Did you read that from a manual, or the back of the oil bottle?

Yes, agreed, why would anyone READ?

 

For me, it's all about taste. Pull that dipstick and slide it along your tongue to get acquainted with the subtle flavors of metallic content suspended in oil. When the flavor goes from nutty to vinegary, it is time for a change.

 

Anyway, not to try to fire up the debate here but has anyone here actually sent out for oil testing over regular intervals while maintaining the same driving method to see when they need an oil change or take two cars in the same condition and used synthetic and conventional oil in the two cars and conducted some semblance of a controlled test over a period of time? I'd love to hear some actual facts and stats... I definitely have not done any of this... and really, isn't it "preventative" maintenance anyway - we should always replace the oil before its ultimate failure point.

 

My measure of how my oil is doing is - "does the engine seem to turn smoothly even though hundreds of other things can affect how it runs?" "can I start up in the cold?" "is it sludgy on the dipstick / during changes?""Does this affect my gas mileage?"

 

Is there a poll of synthetic vs conventional on this forum? I'd love to know where people stand.

 

love this too: http://www.legacygt.com/forums/showthread.php?t=108079

 

As far as "best oil" goes, I have no idea, but of the different oils I have used, the 5w and 0w-30 M1 has worked well for me.

I've used synthetic gear oil in the manual tranny's of other cars and it's almost seemed to be too slick for the syncros. I had poorer shifting performance than with the manufacturer's recommended dino oil.

 

Any thoughts on that as it applies to Subarus?

 

Thanks,

Craig

I just made the switch to mobil 1 full synthetic, and i think i am burning a lot more than a normal rate. i need to check after some more driving but i feel like its burning off more than normal. Any ideas should i switch back to conventional or should i just stick with synthetic?

Use synthetic. This is an open ended question. Use the oil that you ran in your engine and had tested to be sure it is working properly. Testing your oil is the only way to know....period. Testing is cheap and easy, I have it locally done for $25.00 a test.

 

I personally used Mobil1 synthetic Extended Performance 5W-30 with the Extended Performance filter. I've had it tested up to 6,000 miles of my type of use/driving. I do two oil changes a year and test it once a year.

i apologize for my ignorance, but what do you mean tested?

http://www.blackstone-labs.com/engine-types.php#GasEngine

i apologize for my ignorance, but what do you mean tested?

You are humble to say that. No problem, testing or more accurately analyzing the oil usually involves draining your oil at oil change and collecting about 3 ounces of oil while it is draining. Usually there is a form to fill out that documents type and weight of oil, amount of miles, etc. The oil sample gets mailed to the testing laboratory. The lab will contact you with the results letting you know how dirty it is, how diluted it is, and how much of the additives are left, life is left in the oil.

 

For instance I can get 6000 miles out of the oil I use in my car and the type of daily driving I do. If I changed my oil at 3000 miles it would be a waste of time, material, and money.

 

Let the lab know you want to extend the oil change interval and they will let you know about how many miles more you should try. I started at 3000 miles on the oil, the had it tested. It passed, so I went to 4000 miles, and so on in 1000 mile increments. When I got to 6000 miles I stopped there. That suited my needs to change oil twice a year.

 

http://www.blackstone-labs.com/engine-types.php#GasEngine

Yes this is one of the online mail to places to have oil analyzed.

using the fluids recommended by the manufacturer is best in most cases. However I have found that the newest Subaru ATF is bad news for the older E4AT especially when the temps are routinely in the -sub 30s.

 

This last AFT change I switched to Valvoline AFT and put in a new life time filter. Improvement in transmission behavior was immediate. Shifts smoothed out and the transmission does not experience massive load shock when coming off of the throttle when you let your foot off of the gas after accelerating..

I forgot to note I have a 5MT trans. I put Mobil synthetic trans fluid in it. It is hard to downshift into 1st and 2nd gear without rev matching in the cold winter months. Once it is warmed up from driving it is better. It does shift better than it did with the mystery fluid that was in the trans when I bought the car.

Yeah i have a Auto trans, i just use the dexron III which is what is listed in my haynes manual for repairs for the vehicle? in regards to my oil, i switched to mobil 1 5w30 synthetic and it seems like im having to add a bit every 400 miles? i think i am going to switch back. As i live in Southern California and our coldest nights in the winter are in the low 40's to high 30's at the lowest i will be fine with conventional 10w30. Also my local Subaru mechanic who i trust and feel is honest, they recommend 20w50 for our southern cali subaru's since it does stay so warm down here for the most part, what do you guys think?? should i try and get a 20w50 synthetic or 10w30 synthetic??

You are comparing apples and oranges. You can't compare 10W30 conventional to 5W30 synthetic. At least compare the same weights.

 

One disadvantage to synthetic oil for the engine, trans, diff, etc. is that it is more prone to leak past worn seals.

 

I highly recommend the Mobil1 Extended Performance Synthetic, I have not had issues with leaks or burning oil any more than normal, and I have 193,000 on my EJ25 engine.

 

I run 5W30, if I remember correctly that is what the owners manual recommends.

 

For a daily driven street car you don't need to run other than what is recommended. If you run a heavier weight you are going to hurt your fuel mileage. You aren't racing it so you aren't at high RPM on a regular basis. Usually a performance engine is running at high RPM, like a track car 4K to 6k RPM 80% of the time or an inboard outboard boat engine is where you see a 15W40 or 20W50 used.

 

Oh, and please tell me you are NOT running a Fram oil filter. They are garbage all day long no matter how you look at it. Be careful running thicker oil, you run the risk of damage just like if you run thinner oil. Don't go to the extremes. As for the filter don't go too high of a micron filter, like the pure one (gold) either especially with thick oil, at higher RPM you run the risk of starving the engine for oil.

Blackstone labs is a rip off. I sent them perfectly fine used motor oil and sent them one from a motor completely destroyed(spun bearing, floated a lifter) and they said they were both fine.

 

Castrol is a zinc based oil while most (beside Pennzoil platinum:,natural gas base) are wax based. In terms of anti-wear Castrol GTX convention(white bottle), Valvoline High mileage(red bottle) are the two best oils. For cold weather starts mobil1 is the best.

 

As long as you used DexIII in your trans you'll be fine just don't go with a house brand, they have bad rating in the cold. Go with Valvoline or Castrol ATF.Tons of people use this with no problem. I'd stay away with experimenting with Royal Purple or Lucas.

 

Here is everything you need to know about oil filters.

http://garage.grumpysperformance.com/index.php?threads/yes-the-oil-filter-you-sellect-does-make-a-differance.117/

we finally had some sub temps and that Valvoline ATF completely cured the known issue to accumulator charge delay between 2-3 resulting in a delayed shift -17F and it shifted fine through all of the gears. definitely using that stuff from now on...