Root cause of majority of engine failures?

[StreetCreeper]

What truly causes engine failure? By failure I mean the engine is completely shot and you either rebuild it or replace it.

I'm intrigued by engine failure and all the root causes. The idea that some of us have engines that are very well cared for and they still take a complete dump on us at 85k, while other engines like mine, were neglected all their life and yet run fine at nearly 400k — Wtf?

If you could take dead engines, and trace the failures back to their origins — what do you think would be the most common failure source? Or would it essentially be even amongst all the various ways to start the failure process?

If there was only one tip or piece of advice you could give your child regarding how to care for their first car or truck — what would it be, in ten words or less?

 

[Singtoe]

Oil changes

 

[CO98SR5]

Warm it up before driving in cold temps.

 

[Technoplasm]

Warm it up before driving in cold temps.

Is this really that important? I usually do it if I'm not in a rush but I still have my doubts

 

[trovergraywilson]

Cracked the head on my old beater Rodeo. Learned a lot.

Coolant flushes, oil changes, tune-ups. Gotta educate yourself.

 

[ToyotaBrah]

Lack of maintenance. Also, a lack of awareness that high-mileage motors will consume more oil.

 

[Troybylt]

Lack of maintenance. Also, a lack of awareness that high-mileage motors will consume more oil.

Just over 226k on my 5S and the level is always right were I left it after 10k mile intervals. Been using amsoil 5w30 for the last 40k. I have done my valve covers, tube seals, rear main, and PCV as preventive after I bought it with nearly190k. Not a drop on my garage floor or skid pans.

 

[T4R2014]

Warm it up before driving in cold temps.

This is complex. I usually let it run for a minute max when it isn't blistering cold, and then drive off gently until it gets to temperature. Doing this also warms up the transmission. If it is utterly freezing, I will probably let it run for at least five minutes so that the inside can heat up. Even if it gets to operating temp, I would still drive gently to warm up the transmission. Once it does warm up(I'll say about ten minutes of driving), it's hammer time.

 

[mtbtim]

Oil changes

Couldn't agree more. The single best thing you can do for your engine is regular oil changes. And on the same subject, keeping your other fluids like the transmission, transfer case and differentials in good shape is also a good practice to prolong the life of those drivetrain components as well.

As for warming an engine before driving, I've never bothered. Put 240,000 miles on a Honda Accord and I currently have 320,000 miles on a Subaru Outback and I never let them sit at an idle and warm up before driving. But, I also don't put my foot into it and really push the engine when it's cold either.

 

[Konkordmusk]

Couldn't agree more. The single best thing you can do for your engine and is regular oil changes. And on the same subject, keeping your other fluids like the transmission, transfer case and differentials in good shape is also a good practice to prolong the life of those drivetrain components as well.

As for warming an engine before driving, I've never bothered. Put 240,000 miles on a Honda Accord and I currently have 320,000 miles on a Subaru Outback and I never let them sit at an idle and warm up before driving. But, I also don't put my foot into it and really push the engine when it's cold either.

Unless you lived elsewhere prior to Norcal, it definitely doesn't get cold enough here to worry about cold oil viscosity.
In my opinion, I don't believe in a warm-up period for longer than a minute. Your engine does not reach optimal fuel burn until it is at operating temperature, and the fastest way to get there is by driving, not idling. I had some data on the fuel efficiency while hot vs cold for the 5vz but I lost it, I think.

 

[csp]

Mine was allowed to run out of oil by the neglectful prior owner and the drivers side cam broke at the front of the head.

I found that the oil filter wasn't tight when the old engine was removed.

These engines warm up so fast that there's no need to let them sit for any length of time. Last winter at -14F mine was up to temp less than two miles from home with no extra warm up time given to it. Oil gets up to operating temp faster than the coolant does as well. Just go easy on the throttle.

 

[Rock_Rat]

Regular maintenance - Oil changes! Mine doesn't leak a drop or burn oil.

 

[GangsterOfLove]

It seems that what kills most modern engines is cracked heads and head gasket failures.

I'm not sure how you maintain your way around that.,

 

[StreetCreeper]

It seems that what kills most modern engines is cracked heads and head gasket failures.

I'm not sure how you maintain your way around that.,

But let's backtrack a head gasket failure. What usually causes a head gasket to fail? Bad luck, poor head gasket design, improperly assembled at the factory or maybe just over-heating the engine?

I'm guessing the engine over-heated at some point (or points). If over-heating is the reason, then what caused the over-heating? For the sake of this discussion, let's say the engine over-heated because the water pump failed or was failing. So, why did the water pump fail?

If we keep going backwards, eventually we come to one pivotal moment that ultimately decided the fate of that engine. It might be something small like using some crappy additive or other junk to your coolant that killed the water pump, or maybe the owner cheaped out on a timing belt change and didn't replace the water pump or replaced it with the cheapest parts store junk pump he/she could find...

Something started the failure process. It's unlikely any engine just spontaneously fails for no apparent "good" reason. The root cause of engine failure is what I'm most curious about.

 

[mtbtim]

It seems that what kills most modern engines is cracked heads and head gasket failures.

I'm not sure how you maintain your way around that.,

Not really sure on this but aren't most cracked heads a result of overheating your engine? I always keep an eye on my gauges while driving. I was recently driving home from work in my Subaru Outback and saw the temp gauge rising quickly. I immediately got off the freeway and found I sprung a leak in my upper radiator hose. If I would have caught it late and the temperature really spiked, I might have done major damage.

Head gasket failures are fairly common but not a death sentence for an engine. On the Subaru again, I had the gaskets go at around 130,000 miles which was a common problem with those engines. It was a very expensive fix since it's a transverse mounted engine and they have to pull the whole engine out to get the heads off. But, I've gotten a ton of use of this vehicle, currently at 320,000 miles, and I've driven it pretty hard. If I blew a head gasket on my 4runner, I wouldn't hesitate to dig into the engine, resurface the heads and put new gaskets in because I know these 3.4 liter V6 engines can go into the 400,000's and I've only got 140,000 currently.

 

[mtbtim]

But let's backtrack a head gasket failure. What usually causes a head gasket to fail? Bad luck, poor head gasket design, improperly assembled at the factory or maybe just over-heating the engine?

I'm guessing the engine over-heated at some point (or points). If over-heating is the reason, then what caused the over-heating? For the sake of this discussion, let's say the engine over-heated because the water pump failed or was failing. So, why did the water pump fail?

If we keep going backwards, eventually we come to one pivotal moment that ultimately decided the fate of that engine. It might be something small like using some crappy additive or other junk to your coolant that killed the water pump, or maybe the owner cheaped out on a timing belt change and didn't replace the water pump or replaced it with the cheapest parts store junk pump he/she could find...

Something started the failure process. It's unlikely any engine just spontaneously fails for no apparent "good" reason. The root cause of engine failure is what I'm most curious about.

I think the reason has been already stated. It's basically inattention to your vehicle. Forgetting or not caring about changing the oil. Not paying attention to your gauges and not catching it quick enough that your engine temperature is spiking. There are flaws from the factory, like the head gasket issue with my Subaru Outback, but like I stated above, it's not necessarily a death sentence for your truck. I guess it all depends at what mileage something occurs and whether you feel it's worth the time and expense to fix it. I'm so glad I didn't junk my Subaru when it blew a head gasket because that's been an awesome vehicle and I'm going to drive it until it's deader than dead. Same goes for my 4runner. I plan on driving my rig for a very long time, unless I get creamed by one of the many stupid distracted texting drivers on the road.

 

[SnowLizard]

Time

if it's being used or not, in time, everything dies or wears out.

 

[CO98SR5]

Is this really that important? I usually do it if I'm not in a rush but I still have my doubts

I'm talking when it's close to freezing or below. I had a '97 Mustang Cobra when I was 20 that developed cracked piston skirts from starting up cold and romping away. I wasn't so aware back then... But living in the mountains in CO without a garage, my Runner would see plenty of winter mornings below 10 degrees. Maybe it's just peace of mind, but getting the oil up to temp before driving away just feels like the right thing to do.

 

[Drcoffee]

I would say poorly designed with hot spots and oiling issues. Then abused by poor maintenance.

My kids RAV4 has the 2.0 engine known for coking on the rings and sludging. Nothing a consumer can avoid. Especially when the oil capacity is only 4 Qts.

Had Toyota designed the heads and cooling passages better on the 1996 4runners the heads would not crack.

 

[Bstrom]

I've got a '99 4R with 190k and a '03 Tundra with 174k - neither seem to burn oil and run beautifully. These vehicles have not been past the Mason-Dixon line...

It'll be different for folks in cold climes vs. those of us in the southern areas. I warm up for 30 seconds every time, a minute or more after a frost, and 5-10 minutes below freezing depending on temps. This gives everything a little time to move - tranny included.

A lemon will die early anyway.Beyond that, a well maintained vehicle will last assuming all the consumable are attended to. Beyond that, it's probably your fault!