Sad news and spreading the word. Yesterday my 2015 STI 17k miles started knocking. I put the OTS cobb stage 3 kit on it at 12k miles and the car has been absolutely flawless, the perfect DD. On the way home in traffic the engine started knocking. Very strange. At home I checked the oil and it was slightly above full and smelled slightly like fuel. This seems to be common smell. The oil was just changed at the dealer a week prior.

Other than that I dont know what went wrong. It was towed and is now waiting on dealer to dissasemble to find cause and weather or not they will cover it. If not, I'll get a built bottom end. So a win/win just ones more expensive. lol

I'm in my late 30's and consider myselves a responsible driver. The car has been babied 90% of the time the other 10% impressing friends or a spirited drive home.

My theories.

1. Dealer reflashed ecu during oil change? Causing rich / fuel dilution / bearing failure. Car appeared to run normal though. Not sluggish indusive to rich conditions. Will check when I return to make sure the stage 3 is still in it.

2. Ringland failure / oil dillution / bearing failure?

3. Dealer used wrong oil? Doubtful

I did research prior to installing the kit and was aware of the issues but thought most problems occured because most were kids who beat on their cars or didnt change their oil or a hodge podge of parts with a hodge podge tune. This car could not have been treated nicer, and was exactly how Cobb intended it.

I havent seen any reports of any failed 2015's. So figured I'd let you know.

This is not meant for a scare tactic. Just an FYI. The car with the stage 3 is so perfect I would do it again in a heartbeat. As long as I understand what broke and why.

Advice for anyone reading. Use high quality motor oil. Monitor it often. If it seems wierd take a sample send it off for annalysis and change it.

I'll update as I learn more.

 

The 2.5 engine is crap and the issues have never been rectified.
Dealer will blame you for mods.

 

It has been known that some mapping issues and the tumbler valves working all the time in sports #. But this normally ends with poor power and slight hesitation

Tony

 

Update,
Well, Subaru of America said they would cover the disassembly of the engine in order to discover the cause of engine bearing failure. If it is determined that the COBB tune was the cause, The Service Manager said he is going to contact COBB on my behalf to see if they can work something out. No telling if anything will happen, but it was nice of them to say it. Still waiting.

 

Cobb won't be liable / although not unheard of its more common for other components to fail prior to the bottom end on stock internal 2.5's
Crank & rods are pretty good but the bearings can get punished esp if your dropping gears at high RPM's or oil thining out beyond its given tolerance... Debris & pick up could also play a factor )
Sorry for your hardship but please post their conclusion

Regards mic

 

Update,

After the engine was disassembled, it was determined that Subaru of America would cover a replacement short block. I just got the car back today with the stage 3 still installed. I tried to get a definitive answer to the cause of the bearing failure but none was given. Was it the oil change? Was it the Cobb Tune?

Car runs great. Was told to drive 3k miles then come in for an oil change. After the oil change, just incase the Cobb Tune is causing problems, I'm going to get pro-tuned. Scheduled for July 21st at IAG by JR, Cleo is booked till August .

This problem sucked and I was not expecting Subaru to cover it. I was pleasantly surprised. I have nothing bad to say about my experience.

 

Fair play. Good on Subaru too for getting it sorted.

 

Very interesting read, thanks for sharing

 

Subaru America seem to be a lot better at this than Subaru UK / International Motors.

Glad you got it resolved.

 

Glad you got a resolve , I pretty much figured you wouldn't get a "definite " answer
They tend to keep failures pretty tight lipped / although can be said of most manufacturers really .. It would just open the can of worms & create more histeria... I've never opened up a 15/16 block so I couldn't really tell you if there manufacturing processes have evolved in terms of given tolerances & design improvements . But all in all you've walked away with a fresh start . Enjoy the car & good luck for the future

Mic

 

Hi, you say you put the the cobb stage 3 in by yourself? was it even intially mapped after by cobb or another tuner?

 

Yes, I did the Stage 3 myself and uploaded the downloadable Cobb Stage 3 map via the access port. I was very impressed with the kit. Everything installed flawlessly. The car started right up, idled, ran, drove perfectly from day 1 until rod knock (5k miles, 5 months ish).

Today the car is still driving just as wonderfully as it previously.

Still have no idea what cause the issue.

 

ah ok if it was me, a tune by a mapper would have been a necessity. Not saying with that the failure wouldn't have happened, but any reasonable tune imo should be followed by a mapping session.