Anyone's engine fail after an OK compression test?
 

Has anyone's engine failed (loss of compression) months or years after an OK compression test?

Mine's being tested in a few days, and I'm just wondering if an OK test result means it's OK now and probably for many years (assuming I maintain it), or if it's OK now but could still fail any day?

I realize anything can happen, but if it made it 78,000 miles without losing compression, is it likely to continue to be OK?

What is the dealer cost of replacing a failed engine (out of warranty)?

Generally these engines do loose compression overtime. Just because you have good compression now does not mean it will last. However, if it is well taken care of, the engine will not just "fail any day". Loss of compression is a slow process in most cases.

After the 8yr 100K mile warranty, an engine replacement will go for 4-5K. Keep in mind, most engine replacements are also remans, or remanufactured engines. Im not sure what a brand new engine would cost.

Compression loss is a function of time. As time passes (driving car), your compression will go down, how quickly or slowly depends on many factors of course.

So to answer your question, absolutely, especially if the engine is borderline now, it will fail sometime in the not so distant future.

Do you have the numbers from the compression test? Most of the time they will not make note of it unless you ask but it would help to know the results.

That said RX-8 rarely "pop" or outright "fail". I have been on here since 2/2004 and have seen very few posts about blown N/A engines that leave one stuck on the road. The typical failing engine has lower performance ant gets worse and worse and warm starting issues. The compression will degrade to a point where it just isn't drivable any more.

I'll know wednesday :)

Well that's reassuring to hear ;) My worry was that once out of warranty, it might suddenly just be gone one day without warning, and I'd be looking at a new engine cost. I know that can always happen with any car, but I was fearing it more likely with the rotary.

I suppose I'll just make it a yearly thing to test the compression from here out to keep an eye on the progression (even if I end up with a new engine)...

There are ways to slightly gain compression as well. There are many people on the forum who are out of warranty and use products such as seafoam or the Zoom Zoom engine cleaner from Mazda to boost compression slightly until they can swap the motor.

These are like life preservers for the engine, until you get a new engine for it.