Most common internal engine failure

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This is not a very specific question due to many different engines and/or manufacturers ...
However just curious for those who design, repair and/or rebuild engines if there are any internal engine failures and/or weak links that are more common.

I don't do any of the above and just worry about oil
grin2.gif
 
I'm not in the trade but from what I hear it's not going to be the bottom end, it will be some aspect of the cam drive probably chain or variable valve timing.
 
Depends really on engine family. Each one essentially has its own "most common" failure mode, almost always where a penny-pincher smacked an engineer's hand.

Subaru EJ- head gaskets
Ford EcoBoost- water pump (undiagnosed failure will ruin the engine from internal coolant leakage)

as far as actual mechanical failures they are generally rare, especially so in the presence of normal preventive maintenance. There's just so much engineering history in the ICE that outright internal failures almost always come from an external failure that was ignored.
 
I've heard some bad things about the Nissan VK56DE, apparently they're really hard on catalysts and when the catalysts start breaking apart they'll get sucked back in the engine because instead of designing an EGR system Nissan just setup the cams to open the exhaust valve during the intake stroke.
 
There was the Cadillac Northstar problem where GM's engineers weren't quite used to how building an engine with solid aluminum so the head bolts they spec'd would eventually strip the threads out of the block and the heads wouldn't be sufficiently clamped down anymore causing issues similar to head gasket failure.They tried to correct it a few times by lengthing the bolt in 2000 and coarsening the threads in 2002, but from what I hear just don't touch any Northstar built prior to the 2005 redesign.
 
I'm going to go with piston rings as the most common form of failure. With the disclaimer that I mean "ring sealing" and not "ring breakage".

It's generally accepted that when compression drops, oil consumption increases and/or emissions increase, the engine is worn out. This is generally due to piston ring sealing, and may or may not be accompanied by cylinder liner wear.

In fact, on Toyota, Honda and Mitsubishi engines, by the time oil consumption increases into the unacceptable range, the low tension piston rings may not exhibit much wear at all. Same goes for the cylinder bore. This can be due to the low tension simply failing to seal, or any number of other faults, including clogged piston oil drain holes (which may occur due to blowby, infrequent oil changes or poor oil choice) .
 
Most common one I've seen is GM's with active fuel management having a stuck roller take out the camshaft.

Next would probably be 5.4 3 valve Ford once again upper end as a lack of lubrication would cause the cam to wear the machined surface on the head where a cam bearing would be. Usually due to blown timing chain tensioner seals bleeding off pressure.
 
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Originally Posted by OilUzer
This is not a very specific question due to many different engines and/or manufacturers ...
However just curious for those who design, repair and/or rebuild engines if there are any internal engine failures and/or weak links that are more common.

I don't do any of the above and just worry about oil
grin2.gif



The most common internal engine failures I've seen are not due to oil or any other fluid the engine uses. Overheating an engine does bad things, as does operating it outside its intended RPM range. Both cause failures of internal parts, but neither can be prevented by one's choice in oil.
 
Not an engine guy but just from living life and paying attention to vehicles, I'd say blown head gaskets and internal water pump failures. Only engine I personally lost was due to a head gasket. It was repairable but the cost exceeded the value of the vehicle.
 
Originally Posted by SubieRubyRoo
Depends really on engine family. Each one essentially has its own "most common" failure mode, almost always where a penny-pincher smacked an engineer's hand.


Ford EcoBoost- water pump (undiagnosed failure will ruin the engine from internal coolant leakage)



Not an ecoboost engine family problem but a cyclone v6 engine family problem. The 4 cylinder ecoboosts, 2.7 v6 and 3.5 ecoboost in rear wheel drive applications are all external water pumps. The 3.5, 3.7 and 3.5 ecoboosts in front wheel drive platform vehicles are the ones with internal timing chain driven water pumps.
 
Guess it depends on the engine. The Triumph 1500 in my MG is notorious for weak thrust bearings, crank bearings, and rod bearings. Some of them were known to launch rods through the block if things got really bad. The 3.6 in my Traverse was notorious for worn timing chains. The 2.4 in my wife's Equinox is notorious for bad piston rings. These were problems even if they are maintained.
 
Over heating is why companies have long warranties on oil related failures. Forty cars and my only two engine failures were overheating and one of those was a Corvair- air cooled but cooling fan belt fell off at every opportunity.
 
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Most common across the board is cam components I.E. rocker, gears, timing chains. After miles get up we also see carbon in ring grooves causing oil use. No oil is preventing this.
 
Maintenance failures are probably the most common. Poorly maintained cooling systems with leave you with the aforementioned head gasket issues. As a bonus, get them hot enough and you add exponentially to the issue. Didn't change the oil regularly?!? then timing issues for you that may result in the loss of an engine. I remember having to always [censored] with the quadrajet carb on my el camino when I was a kid. It was also common to have to put on a water pump after buying a used car or truck. They are miles and miles ahead of that stuff now. Driven normally and well maintained you can get plenty of trouble free miles from just about any engine on the market. (with some notable exceptions)
 
Originally Posted by Tdog02
Maintenance failures are probably the most common. Poorly maintained cooling systems with leave you with the aforementioned head gasket issues. As a bonus, get them hot enough and you add exponentially to the issue. Didn't change the oil regularly?!? then timing issues for you that may result in the loss of an engine. I remember having to always [censored] with the quadrajet carb on my el camino when I was a kid. It was also common to have to put on a water pump after buying a used car or truck. They are miles and miles ahead of that stuff now. Driven normally and well maintained you can get plenty of trouble free miles from just about any engine on the market. (with some notable exceptions)


not sure why I was censored there... but it wasn't a bad word!
 
Originally Posted by Tdog02
Originally Posted by Tdog02
Maintenance failures are probably the most common. Poorly maintained cooling systems with leave you with the aforementioned head gasket issues. As a bonus, get them hot enough and you add exponentially to the issue. Didn't change the oil regularly?!? then timing issues for you that may result in the loss of an engine. I remember having to always [censored] with the quadrajet carb on my el camino when I was a kid. It was also common to have to put on a water pump after buying a used car or truck. They are miles and miles ahead of that stuff now. Driven normally and well maintained you can get plenty of trouble free miles from just about any engine on the market. (with some notable exceptions)


not sure why I was censored there... but it wasn't a bad word!
The "passing gas" word is censored-I just usually use "futz" or "fuss" or something similarly harmless. My vote is rod bearings if you run out of, or dilute, or mess up oil delivery somehow-that's pretty much always a terminal, catastrophic failure.
 
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