Confused about RMS & catastrophic engine failure
 

Let me preface this by saying that my '02 Box has not had an RMS or catastrophic engine failure that I know of. This question is just for my information. That said, posts on this forum have me pretty freaked out about RMS failure to the point that I look over the floor of my garage whenever I pull the car out to check for oil.

I understand what the RMS is, what it does and how it can fail. Further, I understand that if a Box suffers an RMS failure while the car is parked, it will be flat-bedded to a competent mechanic to have the transmission dropped and the RMS replaced. The owner will likely be facing a four-figure repair bill, but otherwise no lasting harm done (aside to his/her checkbook and marital harmony about spending the anniversary vacation money on fixing the car).

What I don't get is what happens if a RMS fails at speed, or more specifically why an engine may need to be replaced if the RMS fails. Based on my own experience with an oil filter seal failing on a lumbering American V8, when the seal fails at speed, all oil is evacuated from the engine; without lubrication, pistons start scraping against cylinder walls, cams may become scored and bearings eventually sieze. The motor seizes, but chances are good that it can be disassembled and rebuilt.

So if someone were to have a RMS failure at speed, and they noticed the plume of smoke from the back of their car and shut the motor down immediately, why couldn't it be rebuilt? The motor would need to be removed, and probably honed, maybe new pistons and/or bearings installed, but it should be salvageable, no? Even if they didn't notice the smoke and drove the car until the motor siezed, could it not still be rebuilt? It's not as though they put a rod through the block.

In a nutshell, my confusion is that I'm under the impression that Porsche flat-6s can't be rebuilt. With the cost of used 3.2l Porsche motors in the high four-figure range, and 3.4l Carrera motors in the $12-$15k range, I'm wrestling with why a Boxster motor couldn't be rebuilt more cost effectively. Sorry for being so verbose.

I'll leave the RMS issue to others.

It's not that Porsche motors can't be rebuilt - it's that doing so could possibly cost more than a "new" motor. Here's what I was told when I faced having my existing motor rebuilt or putting in a "new" one. It's possible that re-building the motor could be less expensive, but depending on the problem, it could also be more expensive than a new engine. By the time they drop the engine, tear it down, fix the problem, and re-install - you could be looking at serious coinage.

For this reason - when there is a "catastrophic" engine failure, you'll often hear about the new motor. It's generally what they recommend - and it's generally what we end up doing....

Did that help at all?

So it's more cost effective to replace than repair? Wow. The impication is that the cost to repair a P-car motor must then be greater than the $8k-12k to replace. This leads to two new questions. First, is it the cost of parts or labor that is prohibitive? I'm assuming it's labor, but I've also noticed a dearth of aftermarket motor parts so that may be a factor.

On a more fundamental level, I'm wondering if Porsche designed these motors without much thought to ease of repair. If so, what will owners do when their cars all get to the 150k/200k/250k mile range when a major engine overhaul would be in order? A new motor would be far more expensive than the value of the car, but the owner would take a bath if he/she tried to sell the car sans engine. A dilemma indeed.

(I'd probably jump in and tear the engine down myself, but I may not be entirely sane. ;) )

RMS isn't something that fails catastrophically. It's a slow leak, so unless you were driving the car for a long period of time without monitoring and replenishing oil you're not likely to have a catastrophic failure.

On the subject of engine replacement, for "rebuild" type operations the engine still has to be pulled and re-installed. That amount of labor is roughly the same for either replacement or rebuild. So, factoring that out, if the amount you'd spend on the actual repair approaches the cost of a new engine you're better off replacing. If your mechanic says that he can fix it for $8k or replace the motor for $9k which would you choose?

I beleive an used low mileage engine can be had for $2k-4k,depending on the year. Installation can run from $1k-$2k,so it isn't insanely expensive.