It was called “slinging a rod” years ago when it was more common and I have seen a few rod big ends protruding from the side of the block. Over revving was the most common apparent cause but occasionally the bearing shells would “stack and pack,” seizing the rod to the crankshaft and doing serious damage to the bottom end.
As for patching up the engine, that’s out of the question on a Subaru flat engine. It has a split case and complete tear down is necessary to replace a rod bearing.
And as for inspecting the engine to determine the specific fault, can anyone realistically imagine that there would be anything in that sludged up block to avert any guilt from the owner?
I have seen broken rods before, once was my Fiat that broke a rod at 11,000 rpm (est, beyond range of tach but based on hitting 2nd gear instead of 4th at 75 mph) and the other when a rocker arm on the exhaust valve broke.
But as most of you pointed out, the first step would be a seized bearing. I’m saying that if the bearing (rod or wrist pin) did not seize, then the rod was not broken from an oil related issue.
Edit: OK, if the piston seized from oil issues, then that could also break the rod.
So have I, but…have you ever seen a broken crankshaft on an engine that was relatively new, was not over-revved, and was properly maintained?
I am referring to an Austin Marina that was owned by a family friend. It snapped the crankshaft at ~15k miles. The engine was repaired under warranty, and then proceeded to snap the new crankshaft before it had hit 25k miles. Clearly, this was a case of improperly forged parts. I think we all know the stories about abysmal quality of BMC cars back in the '70s!
However, the dealership came to this guy’s rescue…sort of…
They offered him a fairly generous trade-in, as long as he would buy…a new Plymouth Volare from them.
Yes, the Volare was an incredible lemon, and it almost killed him on a couple of occasions when it stalled while on an expressway entrance ramp, but at least the Volare did not suffer from crankshaft problems.
“have you ever seen a broken crankshaft on an engine that was relatively new, was not over-revved, and was properly maintained?”
Not seen one, but a recent discussion elsewhere on OLD Volvos talked about the B16 engine (1.6l 4) with only 3 main bearing, and its ability to do that. Replaced by the 5-bearing B18, which was very reliable (at least in comparison). This was in the '50s, I think.
"Replaced by the 5-bearing B18, which was very reliable (at least in comparison)."
Well, I can report that a broken crankshaft was one of the few serious problems that I didn’t experience with my POS '74 Volvo. I would list the problems that I did have with that evil machine, but I fear that Car Talk would run out of bandwidth if I did that.
Years ago one of the McParts stores asked me to inspect an engine that they had recently sold that locked up while being driven home on a county road. A rod had cracked the block and locked the engine up solid and the amount of oil on the engine and remaining in it indicated that it was not from lack of oil and the owner was a middle aged farmer. I couldn’t determine the cause and I was sent another engine that I installed. On my test drive the transmission would not shift out of 1st gear and it was full of fluid. I called the warranty tech line and filled them in and they called the customer. The truck wasn’t to be released until the transmission was repaired and the owner stopped in to discuss the situation. With him was his son who I found out was totally deaf and was driving the truck when it locked up. McParts was not happy but they didn’t complain. As they say, things happen.
The odds of a metallurgical failure on a Subaru rod are so remote it’s barely worth even considering.
This will more than likely boil down to lack of oil; oil level, oil sludging or coking, etc.
I would think that an oil pan drop if it has not been done would answer any question along those lines very quickly.
Depending upon the environment and driving habits, a 7500 miles interval may not be good enough; especially when factoring in the skipped oil change which just exacerbated the problem.
You probably already understand it’s not possible to tell via the internet what caused this problem. I think what happened isn’t that uncommon though. Newer cars have some compromises in order to post better mpg’s and less required maintenance on their showroom brochures. The thinner synthetic oils for example do increase mpg and hold up longer. But they can also cause oil to be lost a little faster. Some manufacturers say as few as 500 miles per quart loss is an acceptable rate of oil loss. I expect if you look in the fine print that while 7500 miles is the recommended change interval for normal service, they suggest the oil level be checked more frequently than that.
The thinner synthetic oils for example do increase mpg and hold up longer. But they can also cause oil to be lost a little faster. Some manufacturers say as few as 500 miles per quart loss is an acceptable rate of oil loss.
Then some manufacturers are FOS, and should be avoided. If 500 miles per quart is acceptable, then we might as well legalize 2-strokes fer chrissakes.
It can and will happen if you never checked the engine oil level.
A motor can easiliy go 16k without changing oil if it has a decent amount of oil in the sump. However any engine old or new will die a quick death when oil is low and beaten up or missing and no longer can lubricate the engine.
The OP doesn’t seem too anxious to come back here and answer the question about the oil level. I’m guessing that means it was never or rarely checked and that it might have been quite low.
@lion9car–The situation that I have observed over the past few years is that newbies frequently come to this site in order for others to confirm the newbie’s pre-conceived notions–be they valid or off-the-wall.
All too often, when forum members have disagreed with the newbie OP, the OP has reacted with anger and–in a few cases–has referred to some of us as shills for the auto industry, or something to that effect.
I agree with you that the OP is unlikely to return to confirm or deny our worst suspicions, but at least he hasn’t insulted us for disagreeing with him!
For a somewhat different interpretation of OP behavior…think about how it feels to be confronted with your role in the creation of an adverse outcome. (I don’t mean harshly, I mean it in the neutral sense of the word.) I would be embarrassed as all get-out. It can be a bitter pill to swallow, and some lash out and blame others. Others slink away. Still others will own up. Internet imitates life.
7500 miles is for “normal” service on your car. The "severe’ service is 3750. Severe service is defined as driving short trips, driving in cold weather, driving at high speeds, driving in temps over 90, and excessive idling.
90+ percent of cars driven meet the criteria for severe service.
As others have asked, how often did you check the oil? If you neglect changing it and let the level get low, the contaminants get concentrated and the acids and abrasives attack the bearings.
If your owners manual is like mine it tell you to check the oil once a month.
I am sorry you have had such a very expensive lesson.
@cdaquila “For a somewhat different interpretation of OP behavior…think about how it feels to be confronted with your role in the creation of an adverse outcome”
Very well said. I’m sure the others here who deal with the public regularly share the opinion as do I. We may have our own thoughts and judgements but we present them to the customer in as neutral a way as possible.
The conversation in the shop may be “Well, the idiot ran his car out of oil. Too freakin’ lazy to read a dipstick, totally wasted a $3000 engine.”
The conversation at the front counter will be “Well Mr. Jones, your car has major engine damage from lack of adequate and clean lubrication. It appears it may have been too long since your last oil change service and possibly the oil level was low as well. Do you have any recollection of how long it has been since service? Have you or anyone checked the oil level recently?”
The op asked a legit question. Motors can go 16k miles with oil in sump with falling apart. However those type of cars are simply topped off and kept with reasonable amount of oil them.
My girlfriend in college(1990-1994) changed the oil once/year(15k miles) when she took her Camry home to her dad. She did know enough top top oil.
