I've finally hit an even mileage on my odometer since buying this car and I start my 5K mile oil change interval. One key note while changing oil on a STI, you must remove the skid plate under the car to reach the oil filter. Something different from my old 2002 WRX. The skid plate requires removing 3 bolts (2 near the front bumper and 1 in the middle) and 2 brackets (one each near the wheel well)

Besides that extra step, changing oil on the STI was a breeze.

PS. I've seen plenty of questions about how much oil you'll need. It's 4.5 quarts. I'm also using Shell Rotella t6 5w40 synthetic and an OEM blue subaru filter since the previous owner did the same.

 

My 05 is due for a change as well. Trying out the Rotella for the first time, switching from motul, I will send in a sample for analysis and compare the two.

 

that's awesome! i've always used mobil1 5w30 on my WRX. it would be great to see some kind of analysis.

 

Just be aware, Shell states very clearly in their literature that it is not to be used in a gas car with catalytic converters. So if you have them still, don't use it! They really don't recommend it at all, its a diesel oil.

 

idk man, I've read that that the amount of zinc, which is what clogs the cats, is not significant enough to harm the exhaust system. I've ran T6 for over 30k now (started at 170k) and have had no problems with my invidia catted dp. If I were worried about this though, I'd probably switch to castrol gtx. To each their own, though!

 

My car is stock. I have heard arguments about it clogging cats and not clogging cats so I don't think the T6 is going to be my usual oil. I will probably go back to the Motul. I just could not find Motul and my car was due for an oil change.

What oil do you run in your fxt Overbear?

 

So I looked into this deeper too. I used Rotella T6 on my WRX and it was wonderful. The engine seemed to love it (I did not get oil tests). But it burned negligible oil (compared to regular 5w-30 which required 1/2 qt every 3.5k mi), seemed to clean out the sludge (rotella got filthy fast.. but after two rounds the oil stayed "clean"), and the engine purred. My experience doesn't prove anything but it seems to be the expected experience with T6.

The problem lies with the (whatever) ingredient that kill catalytic converters.... but that only happens if you have enough blow by in your engine; because for it to get into the exhaust, the oil has to somehow get into the combustion chamber. Normally a healthy engine doesn't have significant enough blow by to have a problem (although very long term it might be cumulatively bad). Or so I've read.

 

Motul 8100, change every 3000 almost on the button. I only use K&N filters, and changed out my plug for a magnetic plug. Soon to be adding a oll cooler in the fenderwell (driver side) and might add in a 2nd filter (K&N reusable). The goal is to get ready for a E85 tune, and eventually a motor build aimed at 600whp. (many years in the planing not close now)

 

Phosphorus kills cats. Most race oils are very high in phosphorus, same with diesel oil. Here's the thing. On an aftermarket one it doesn't matter it's just a matter of emissions. But there's been plenty of people who are curious to why they failed smog on a stock set up. It's from the use of t6. Not particularly clogging. It's degrading the cat little by little.

 

I don't think I'd run 5k oil change intervals on anything Subaru has turbo charged!

 

This. Every 3k for me.

 

I was using t6 for the last 60k miles. Cant speak as to the degredation of cats as ive had about 4 different catted downpipes.
Im back with the stock now and decided to go with what my local subaru mechanic reccomends for oil which is regular casterol 5w30 with the lucas stabilizer. Even with t6 i would burn a crapton of oil and it would be black by 3k. Yes its diesel oil....yes they took off the label saying its ok in gas engines......lol.

 

Thanks for clarifying that. When I look at my after market cat now (stock dp is on the car currently) I cannot see any degradation. I would assume I would visibly see some, if it were degrading, yeah?

Even without researching more into T6, I still feel comfortable using it for the most-part. I do plan on getting an oil test this year, though. See, I use the cat on my wrx for the back-pressure on the turbo primarily. So as long as the back-pressure is consistent, I'm happy.

 

 

Aside from the 30K/60K or if it's around a major mod install, I've been getting the oil changed at the dealer since day 1. (Dealer being Capitol Subaru.) I literally live about 1/4 mile away so it makes it easy. I go every 3K like clockwork. Strangely enough the past couple of years the sticker they put on the windshield started saying 5K and the past year or so it's actually been 7K. 7K? Really??