It has two years of warranty left... Should I just save the $150?

 

Is $150 a lot? Do you have symptoms that could indicate low compression? If everything is fine then everything is fine

 

$150 seems a little high to me. I can afford it, but I don't like wasting money. The same dealer is going to do a full pre-purchase inspection for me, including a test drive. The car is a couple states away, so all I have at the moment is the (seemingly trustworthy) owner's word.

My thinking was basically, the compression test can tell me only the current state of the engine, and since it's covered by Mazda for 2 more years, it just doesn't seem that important. If it's bad, great, I get a new engine. If the compression is good, great, the engine should be good for a little while longer, but it's no guarantee that the engine will pass a compression test next year or the year after.

The current owner had the compression tested a few months ago, see pic below. I know it "passed", but the 7.4 and the 7.5 lead me to believe it just barely passed. Elevation was 745 ft, and I will admit that I don't know much about compression tests.

Any advice or help interpreting the results would be appreciated. Thanks!

 

well, I bought my 2009 Dec 4 2015, started/drove/ran great, it's at the dealer waiting new engine now, because I had the test done and it was marginally failing.
Hindsight being 20/20, here is what I would do:
- Enjoy it. Maintain it. drive the heck out of it.
- take for compression test say 2mo (or 2k miles) before warranty expires. cross that bridge then.

The reason I say this is because I've heard stories of babied S2's which just needed a good 'whippin', such as a track day or 3. I suspect mine is fine, just carbon'd up, though I've not yet seen the test data.

fyi my local dealer is $120 for compression test and rather complete inspection.

 

If its at the dealer and they are doing a pre purch inspection just get it done at least you know how its going. if its below spec do you still want to buy it?

 

That's a good question. I think I would still want it. Is there any real downside to a failed and replaced engine?

 

Check your scores here for correction.

 

I found that earlier, while searching the forum, but I'm not sure how to use it besides looking at the rpm the engine was tested at.

 

Me neither. I mean, you see the cranking RPM, and the pressure, and if it's in the green, your good, but I'm not sure what measurement those numbers are..

Eg 250rpm and 108psi (7.6kg/cm2, 7.4bar, 744kpa) get 7.80. But 7.80 what? It's on the lighter green, but still a good number, but whats the unit of measure for the 7.80?

 

That would be 7.8 kg/cm^2