279,000 miles - Mitsubishi Mirage engine teardown - top end vs pistons
- Thread starter buster
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As an oil-focused forum, we tend to blame (and credit) oil for many different things when there are usually several other factors in play.
It wouldn’t be uncommon for a delivery vehicle to see extended idle times for example, which could cause such piston deposits. A cold running engine due to a stuck thermostat is another possible cause.
Guessing less idle time and/or shorter oci.
But it might have been for naught, if that wrist pin was wearing out and not due to “bad” oil.
An engine that small isn't exactly loafing when it powers a car at a sustained 70+ mph, especially if there are hills involved.
This just shows what proper maintenance and proper driving can do for any vehicle.
Arguably one the cheapest, and crappiest vehicles on the road and here we have a tear down at 279,000mi.
I drive high miles. I've driven multiple vehicles past 250,000mi. Could have gone more. On one I made a commitment to myself to trade it in at 250,000 miles cuz I was tired of driving it. Another one met it's demise with a deer. That seems to be my deciding factor when a vehicle needs replaced.
The quality o anyf oil has greatly improved over the past decade. The tolerance which engines and stuff are built to keeps getting more keeps getting more. You really can't build garbage anymore. Far to much competition in the automotive industry.
Arguably one the cheapest, and crappiest vehicles on the road and here we have a tear down at 279,000mi.
I drive high miles. I've driven multiple vehicles past 250,000mi. Could have gone more. On one I made a commitment to myself to trade it in at 250,000 miles cuz I was tired of driving it. Another one met it's demise with a deer. That seems to be my deciding factor when a vehicle needs replaced.
The quality o anyf oil has greatly improved over the past decade. The tolerance which engines and stuff are built to keeps getting more keeps getting more. You really can't build garbage anymore. Far to much competition in the automotive industry.
OVERKILL
$100 Site Donor 2021
Reminds me of these XOM slides:
(yes, this one uses altered contrast to make the differences more stark):
And if we look at Sequence VG, even "pass" doesn't look too hot:
It's successor, VH, "pass" doesn't look that great either:
So, do I think a "better" oil might have kept things cleaner and prevented the oil consumption? yeah, possibly. I don't think we can dismiss that as a possibility.
Triple_Se7en
$50 Site Donor 2024
This is an incredible feat this economizer engine has displayed.
Lagging close behind is Member Accent Abuser and his original TGDI engine at 230k and still going strong.
Someday, these two vehicles can promote a race against each other, allowing Member AutoMechanic to be the referee and follow-along from Start-To-Finish in his Yeller' Beetle Bug.
Lagging close behind is Member Accent Abuser and his original TGDI engine at 230k and still going strong.
Someday, these two vehicles can promote a race against each other, allowing Member AutoMechanic to be the referee and follow-along from Start-To-Finish in his Yeller' Beetle Bug.
Should've used Pennzoil for 40% cleaner pistons.
Seriously though, the pistons look bad but apparently did not have much effect on longevity. I've seen much cleaner pistons in dead engines.
Seriously though, the pistons look bad but apparently did not have much effect on longevity. I've seen much cleaner pistons in dead engines.
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I agree 100% that’s why using a Quality Oil like Triax Lubricants or Any of the M1 variants is a Must .
OVERKILL
$100 Site Donor 2021
I agree 100% that’s why using a Quality Oil like Triax Lubricants or Any of the M1 variants is a Must .
Perfect explanation
, I do the GDI valve cleanings,Gumout in crankcase right before oil changes and throw TT fuel 
️ with Redline Si-1. Oils used have only been Redline, Mobil 1 and @High Performance Lubricants ec30 as a top off right before oil changes. Currently at a dash over 320,000 as of today.
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I agree 100% that’s why using a Quality Oil like Triax Lubricants or Any of the M1 variants is a Must .
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Got to move that oil from behind the piston and through the oil rings. Perhaps a better designed piston and oil ring to move oil would have made a difference.
But still engines don't last forever and it seemed to have done well for a long time due to the relatively low miles on oil changes.
But still engines don't last forever and it seemed to have done well for a long time due to the relatively low miles on oil changes.
Waoo , impressive for a little car like this Mirage to achieve that mileage. I can believe the Mitsubishi 4G15 engine used on previous Mirage and other models can achieve that mileage, but not on this little 3 banger. Awesome.
What oil grade type brand did the OP use?
I see mobil 0w40 new life listed. Would all Mobil one oils clean as good? I know 0w40, extended performance are known too clean sludge.but the other Mobil oils?
It sure does show the differences from semi synthetics too fake full synthetics .and severe driving conditions .
I was gunna use semi synthetic again next oil change.but so thinking going back extended guard. Alot stop go traffic idiling here, months extreme cold or humidity. march-june good conditions , October to December cold but good for semi synthetic. Jan-feb harsh 27 degrees or colder , July September 97 plus degrees and huniditt and idiling stop go traffic ..Mobil oils are PAO? Clean much better than the others
This is a 2015 car, so even if the oil brand stays the same, the formula changed at least 3-4 times over the lifetime of this car. SN, SN+ SP and different iterations of addpack within those designations. I maintain it is an engine design issue that gave reason to open it up, rather than oil quality. The loose wristpin is a giveaway. Not much oil getting up there. What did get there was kept there and clogged the oil holes in the wristpin bore. The rest of the engine was very very clean. Doubt it was run too cold.How many other vehicles used the same fleet oil and did not experience piston coking over this same period?
Bah!! Some MMO would have cleaned those pistons right up. 
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