Best oil for N/A 2005 Impreza

[Maxxguy25RS]

Like the topic says. Im curious to see what everyone is running for motor oil, and gear oil in their cars. I want to make sure im doing my engine and driveline good. Ive been using Penzoil 5w30 conventional and it seems to be working ok. I did notice a little bit of consumption last change, about 3/4 of a quart low, maybe a little more. and to add to it, I thought it looked really burnt.

I have been looking into changing the gear oils too. 109000 miles and I dont know what its got in the gears for oil.

whats best? whats worst? conventional? synthetic? blends? 3000 mile interval? 4000 or 5000 mile interval?

any information is good information. opinions are good as well. just curious.

 

[Mighty Subie]

Well its not really a good idea to swap from dino oil to synthetic after so long. The big claim is that the synthetic is 'thinner' so your bearing will actually have a looser tolerance than before. So sticking with dino will be good for engine oil. 5w30 is normal. And if it is having oil retention issues, adding synthetic will not help.

I hate to make a suggestion on what exact oil to get though because there is always someone who will say you are wrong. A lot of people run mobile 1 75-90 gear oil. I personally have. I didn't have any issues. A good 75-90 will be fine. It should tell you in the manual this also. Just remember that if its an auto, it does not take gear oil in the trans. It takes a specific auto oil.

 

[Pedro]

Just remember that 5W30 is the lowest viscosity oil that subaru recommends.

I wouldn't hesitate to switch to synthetic. Synthetic and 'dino' oil use the same base stocks (processed crude). Mobil 1 tends to be thinner than the bottle suggests and can have some consumption issues with that.

I run synthetic (164kmi 2.5l WRX) with 7000mi change intervals. My miata has run a bunch of different oils synthetic and conventional. The only real problem I had was that the 5-30 mobil 1 would gush out of one bad seal much faster than anything else, upping that to 15w-40 solved that for the most part (still needs a new seal though).

 

[2point5RS_Dan]

10w30 Castrol synthetic.

Used to run 5w30 mobile 1 and would gulp down a quart after 2000k miles on the dot.

Switched to Castrol 5w30 and it didn't consume oil, but was a bit too thin for my liking.

10w30 helll yeahhh the sweet spot. Blackstone report said all is good (even though you should take blackstone with a grain of salt)

Weight > brand.

 

[i-wagon]

I use mobil one synthetic in mine, have for the last 50k. I start to lose a little bit when its time to change the pcv valve ( if yours hasnt been done, do it they're $20 and easy to do) I change mine every 4k, people say I'm wasting it but dont care. 75-90 in the manual tranny, using lucas synthetic in that and rear differential. the synthetic oil will help with cold starts, and the gear oil helps stiff shifting in the cold, mine's like a whole new car compared to when I bought it with dinosaur in the engine and tranny

 

[Chris]

10w30 Castrol synthetic.

Used to run 5w30 mobile 1 and would gulp down a quart after 2000k miles on the dot.

Two million mile OCI FTW!!! haha.

I run 5w30 in my car. It cranks nice and fast when it's cold out, and doesn't make any really terrible noises. It's a 2.5 DOHC (block) with something like 240k miles.

 

[Jamey]

I use aimsol in my 2.5i Proubly a waste money I usually go 7000-8000 miles

 

[2point5RS_Dan]

Two million mile OCI FTW!!! haha.

I run 5w30 in my car. It cranks nice and fast when it's cold out, and doesn't make any really terrible noises. It's a 2.5 DOHC (block) with something like 240k miles.

Blah, extra unesscesary K.

 

[Matt]

You should be running something heavier as the miles go up. 10-40 in my rs with 150k and a burning issue. Car hates 5-30 and hates Mobil 1... So thin.

 

[Maxxguy25RS]

so the regular oil will work when I change it on the regular intervals. I might try the 10w30 next time to see if that makes a difference. is there a common theme with a slight engine knock when cold? cold like first start on a sub freezing morning with frost on the window cold. would the synthetic help with this?

I do know that synthetic can allow a longer change interval. ive also heard that if you run dino for a long time, then switch to synthetic, it will ruin seals and cause problems rather than correct them. I ran mobil 1 in a honda that I owned and it started to leak after I used that. it had around the same miles as my subie does now.

but, as pedro said, I have noticed the mobil tends to be thin compared to even the cheap napa oil my work uses for oil changes.

ive heard from the turbo guys, the premium synthetic, like amzoil or royal purple are great for those cars. I would have to guess they will do just as good for my car. even the castrol oil is good, and its usually a few dollars cheaper than the amzoil and royal purple.

I will only use the factory filter too. no I dont kno if that just me being stubborn or what, cuz honestly im unsure about using another. my work uses napa filters, ive put napa filters on personal vehicles before and I dont think there is much of a difference other that the price if half for a good napa filter than the factory part.

 

[i-wagon]

mine's knocked when cold since I bought it brand new 5 years ago. just something they do. you'd probably be better off buying a good conventional oil in 10-30 and see how the car likes it.

 

[jaKe]

I would add it depends on how you operate it. My car uses whatever oil I can get that's near 5w-30, dino, syn, longlife syn, whatever. It gets revved to 5k regularly (its 2.5sohc n/a pos) and knock is much better cold with "thin" synthetic oil. Only ever issue I have had with any oil is Mobil tends to leak.

In my wifes 07 forester 2.5na I had run syntec but decided since I do 3k oil changes and she doesn't use it hard run good ole gtx 5w30 (winter) and 10w 30 summer. (she dont like to wait for it to warm up so need that oil thinner in winter) Oh and had run Mobil 1 in this back in day now have started leak off drivers head oil return port, probably was inevitable but I beleive was faster leak on Mobil 1.

also I have started running oem subaru filters in both, cost no big difference not sure if any better. BTW anyone know of an alternative to the tiny subie filter? I would like to run a larger one on my car and push back oil changes more.

 

[Mighty Subie]

also, a rule of thumb is that it's ''more okay'' to run thinner in winter and thicker in summer. In hotter temps thicker oils are better. So don't load up on the thick stuff for winter. Keep that in mind. (your manual should agree with this if you look at the funny oil chart that most manuals have)

 

[Maxxguy25RS]

I will keep the thicker oil in mind when the temps warm up a bit. but im thinking the dino oil should work fine. and its easier on the wallet as well

 

[Gate4jg]

In my 08 impreza I put valvoline 5w30 synthetic in my car every 6k and a mobile 1 performance oil filter. It works great.

 

[Maxxguy25RS]

I feel like I keep changing my mind on synthetic or not. I kno the dino works just as good. and the synthetic gives you longer changes and better wear protection and heat protection. for some reason I feel it has a lot to do with personal preference too. as long as the synthetic works better, I dont see anything wrong with using it. im set with the weight of the oil. thinner in the winter and a little thinker in the summer. I guess ill have to just decide on the two next time I need an oil change

 

[Pedro]

you are making way too big of a deal out of the choice. NA motors unless raced are pretty easy on oil. The subaru motor is not a high HP/litre engine so stick with conventional if you want. Or switch.

I use syn because I have a 100mi/day commute and I don't feel like changing my oil every month.

 

[CoupedUpSubie]

The only reason switching to synthetic would bother any seals is if the oil had been repetitively used for long periods of time. Then it is said synthetic will clean the junk up and cause leaks. Even with synthetic I don't go any longer then 5k miles between changes. Amsoil claims if you use their oil and filter you can go 25k miles or 1 year on a change. My opinion, try different oils and find what works for your car. For some odd reason some cars like certain oil.

 

[Chris]

Personally I've found that if I have oil in my engine, it keeps running and it's happy. And when something happens and there's no oil in my engine, it stops running and gets all seized up...

So my conclusion is that if I put any kind of oil in my car, it works great.