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.

I'll have to ask him all that then.

He did not have an oil cooler... I have a 2013 BRZ and have not had any problems with it yet. Hopefully she stay's healthy for a long time. Just put exactly 5.8 quarts of mobile 1 in it yesterday. Oil level is on the dot.

I really wanted to tune my car but I think I'm going to stay far away from them now... not worth it...

probably not.... can't you hear that anyway?

Is his DI in good condition . I found it coz alot of damages in engine and I believe it is main reason for throwing rods from the engine .

Its not the first Subaru engine to blow that was using Mobil 1... But its probably not the only factor.

DI? Not familiar with that acronym..

You don't reccomend Mobile 1? Can you explain? I thought it was top notch... :(

Direct injection

Hell I'm sure he didn't/doesn't know if it was or not.

What tune did he have? And how long has he had it? Or where did he get it tuned at?

The stock tune isn't that great either, I forgot what the issue was. I think it was the injector seals. Seal breaks, cylinder runs lean, boom.

Does he have a lightweight crank pulley?












:lol:

By the time you hear it knocking, most of the time it is too late. There are micro knocks which super sensitive sensors can see/hear before our human ears can even detect anything.

Forget oil weight, how often was he changing it (not this most recent change, the previous changes)? Was it full (not overfull)? Is he running too rich and washing down the oil with fuel?

Make sure he sends the oil out for proper analysis.

Post hoc ergo propter hoc

It runs thin for what its supposed to be rated for, and burns out faster than the 7500 miles people try to use it for. I saw dozens of blown motors running mobil 1 when I worked at a dealership for a few years, part of it is because of issues with the oil weight but most of it comes from the owners who expect it to be bullet proof and its not because no oil is.

If you insist on Mobil 1, run 0w30 instead and change it frequently (3000 miles) especially if you abuse it.

i've been driving 3500mi. on this Mobile 1 Extended Performance 15,000 mile rated oil no problem so far.

direct injectors

is there a facedesk emoji gif on here? Mods can we add one? I think you guys would appriciate it too lol

North American spec Mobil 1 is junk compared to the European spec stuff, not sure about the extended life stuff.

AFR is nothing if the timing is too far advanced and the gas octane is too low.
The fuel will pre-ignite before the top dead center of the stroke and twist the rod, eventually ejecting it out. If tuned on 93 and you put 87 in good bye engine, There is a reason the factory tuning and timing is not the maximum limit of the engine for a safety factor and reliability.

"I have a tune and aftermarket parts, so I'm going to blame my engine failure on my oil."

EL OH EL.

Post Hoc ergo Properter Hoc indeed.

I'm not a gambling man.. would still put all my chips on the tune. Bad gas is a probability but statistically improbable, even in the event of "bad gas" most cars don't lunch their engines, they just run very poorly. So, throwing a rod, even if bad gas was involved is still a fault of tune that was incapable of adjusting for the knock from said gas, not mention you would have noticed a poorly running engine well before you lost it (with gas bad enough to cause a failure). Sounds like a meeting of 2 flame fronts before TDC, and over a period of time it lead to a ping ping ping ping... BOOM.

Probably only happened within a small window of the RPM range so that's probably why it lasted as long as it did. Had this car been tracked or was a track only car it would probably would have failed much earlier.

Bad gas is the last thing that will cause a problem... its way more of a problem if the oil isn't changed frequently enough and gas builds up in the oil degrading its ability to lubricate the engine properly.

pretty sure it was not related to oil, but could it be the failed valve? isnt they updated valves for 2015 model ? or maybe the guy over rev it?

I was speaking to this guy on my facebook the other day, From what he had told me hes running the open flash tablet tune and has full bolt ons. He claims to have changed his oil every 3k and he recently changed it before his engine blew, like 1k miles before.

was it raining heavily when this happened?

If we actually wanted to figure this out (not that we can), the FIRST thing to do is determine what is meant by "thus causing it to throw a rod."

This can mean more than one thing.
Did it "Spin a rod bearing"? - Lubrication
Or did it "break a rod"? - detonation/over-rev
Or did it "break a piston" resulting in a "thrown rod"?

Far too many details missing for us to determine cause.

Too much oil???