How long between oil changes?

[Jake Raby]

I knew I never should have tried to offer an opinion. Thanks for reminding me that I should keep my mouth shut totally on this topic.

But changing the oil would not have kept this failure from happening.. The piston exploded at 70 MPH on the freeway.. Female driver..

We just took this one apart an hour ago. Mofde of failure #21

[jmatta]

My, that isn't pretty. What would cause the piston to explode like that? As you say, oil wasn't the issue here, but frequent changes can help with the other 20 modes of failure.

I'm starting to save up for my IMS bearing replacement...

[Jake Raby]

Component failure plain and simple.


This car was owned by a Female from day one, she never tracked it and it only has 40K miles on it.. You can see how slow she has driven it in the carbon thats built up on the pistons/ etc.

[Frodo]

Originally Posted by Jake Raby

Component failure plain and simple.


This car was owned by a Female from day one, she never tracked it and it only has 40K miles on it.. You can see how slow she has driven it in the carbon thats built up on the pistons/ etc.

Jake, probably a dumb (or at least naive) question: Do you think there's a relationship between the carbon build-up and the failure of the piston? Worded differently, had this car been driven harder, would it have been less likely to experience such a failure? Or was it doomed to fail, sooner or later, the minute it was driven out of the dealership with a couple dozen miles on it?

[manolo]

There's nothing wrong with that motor.

That's the Porsche-Engineered "Inter-Cylinder Pressure Relief Air/Oil/Piston Separator" ™!!

It reduces crankcase pressure between cylinders and allows decreased rotational mass at higher RPM's.


HAHAHAHAHAHA!!!!!!!!!!!!!!!!!!!!!!

[jhandy]

from what i understand, and please correct me if i am wrong.

Speaking from an IMS standpoint. The bering is supposed to be sealed, it is bathed in oil. If oil is getting past the bering and dripping out of the RMS, then it is safe to assume the bering is not sealing.

The plastic seal allows oil to enter, and may not flow around the bering freely and the bering fills full of old oil.

then the old oil breaks down and the bering wears and the IMS fails.

So thinking of that alone, it is better to have as much fresh oil in the motor so that a little fresh oil makes it into the bering and lubricates the bering.

Also from that stand point, driving it hard may push oil into the non sealed bering and replenishing the IMS with newer oil. Hence the superstition that driving the car hard is better than babying it from a IMS standpoint.

does this sound resonable or am i totally of base?

I will say this... I have had three RMS seal repairs. I change my oil every 5 K miles, and my IMS was going out at 65K. I am courious if it should not be closer to 3000-4000 miles for an oil change.

[Jake Raby]

FWIW-
jhandy's car was recently returned to him from my shop...

His engine had 22 out of 24 lifters that had failed.