Blown engine due to 0W-20?
 

A person in my local 86 club recently threw a rod in his FR-S.

Car had 38k miles when it blew and he had just put Mobile 1 Extended Performance 15,000 mile rated oil in his car at 37k miles. So only 1000 miles in. The car had a tune and mild bolt ons. Never tracked but driven hard.

He claims it was a combination of heat and the low oil weight (0W-20) that caused the oil to break down and not lubricate....thus causing it to throw a rod.

I thought 0W-20 was the recommended oil from Subaru...? :iono:

I just put the same oil in my car yesterday... so what do you guys think?

I think it was most likely not the oil.

Bad tune with bad gas

That's why I thought. He swears up and down that his AFR was reading perfect... I guess that's not the only factor though?

I think you should sell the car and never buy a subaru ever again. Stick with a Honda Fit

Been running 0w20 on my boosted FRS for over 25k miles now. No issues what so ever. Most likely not an oil weight issue.

sounds like he's making speculation based on rather limited sounding knowledge

and he's SURE he threw a rod? It might just be crickets...or normal engine sounds. Not trying to sound like an a-hole, but sometimes people hear one noise and jump to some pretty wild conclusions.

Yeah... maybe so

and no I mean his car is completely out of commission. It blew up, lol.

I'm currently using Mobil 1 0w20 EP on my car. Tracked multiple times without issue.

Yep AFR is only one part of it. Was he also monitoring for knock?

Better question, when he was monitoring afr, was it the stock o2 sensor using torque or some similar android app? Unless he has a better o2 and possibly map sensor, torque is a pretty useless measuring tool.

Pssshh... ain't the oil, unless he has logged data to back up more of his story. ^^ Also curious if he's using a proper and accurate wideband afr meter tool... plus you could be dumping mass fuel from an ots tune and run a sub 10 afr and still throw a rod

So he is essentially saying that the cause of the failure was following the exact requirements of the engine engineers? :clap:
A failure that the other 99.99% of the other owners have not experienced? :iono:

Tell him he should become an engine designer.

Unless he has data logs or stares at the afr gauge while driving... :lol:

The biggest factors in a blown engine at low power levels are usually-
-Tune or bad gas(which affects the tune)
-Driver/mechanic, mis-shifted, over-rev, too much/too little oil. Kept on driving when it felt funny, or just driven too hard for too long and did not watch the oil temps.
-Manufacturer, earlier model 2013's have the most problems. But if it was driven hard it would have blown a lot earlier.

Ask him what he was doing when it blew. And how long he was driving hard for. Ask him how many quarts of oil he put in, he should have it memorized @5.8quarts. This car is known to be difficult to check the oil level, maybe he just changed the oil on ramps and did not check on a level surface. Ask the right questions and the answer should present itself. People mis-shift all the time and never want to admit it.

Also does he have an oil cooler? I make one or two passes and my oil temps are already at 230f++
What tune does he have?

I'm going with money shift.