Compression test for a sub 20k car?
 

Hi folks,

I've been a lurker here for years and admiring fan of the RX8 for even longer, and I'm finally in a position to pull the trigger on a beauty that I found with under 19,000 miles on it. It's a 2008 Series I, and is supposedly still under warranty (only for a few more months at most, I assume).

Now, this car appears to have been looked after by someone who seems to know what he's doing. I haven't seen it in person yet because it's a bit of a drive for me, but maintenance records are plentiful and the owner knows his way around the car. (Bonus points: in the photos there's a bottle of engine oil in the trunk). I'm planning to drive up and inspect - and hopefully purchase it - later this week. It's been lightly modded but is mostly stock - the only performance mods are a K&N Typhoon intake and a catback exhaust (he still has the stock parts, especially the intake, thank God).

My question is this: The owner works almost around the clock and is reluctant to take the time out for a compression test. He says it's never been flooded, properly maintained, etc, etc. Given the quite low mileage and regular maintenance (and any warranty remaining), how heavily would you weigh the importance of a compression test? Should I insist on one regardless, or would it be a relatively safe buy if I drive up and find that it's in otherwise good condition?

Thanks!

I always recommend a compression test. Unfortunately, you simply cannot know what you are buying without it. If you can verify it is still under warranty (call Mazda USA with the VIN), you could buy it and take it straight to the dealer and have it checked out.

Call me cynical, but any time I have encountered an RX-8 seller, who is reluctant to have a compression test performed, it has been because he was hiding something or at least wanted plausible deniability. There are a lot of people sitting on cars with bad engines. Some know, and some don't want to know.

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Possibly.
It could also be that in this instance the owner is being truthful, believes it's good, and feels like he can sell it to someone else without a test.

If it's a reasonable price, and the rest of the car is in good shape, it might be worth the gamble.
(As long as it's a stick and not automatic.:))
I bought mine with 18.5k from a dealer without one, but I wasn't aware of the failure rate when I bought it.
55k now, still running good.
(Knock on wood, seriously, I just did after typing that.:))

I can understand the owner's viewpoint, I hate wasting time for something I feel is unnecessary.

HOWEVER, the K&N intake would concern me if it's been on there a while.
Not the best choice of intakes, and I've read that they allow a lot of dirt into the engine.

I drove an R3 with a K&N Typhoon. The noise level was literally intolerable. When I say literally, I mean literally -- no exaggeration or metaphor of any kind. I seriously could not stand to drive the car. It was way, way too loud.

Also, I would never buy an RX-8 without a compression check, warranty or no.

There are good cars out there. It is worth holding out. Good luck, and keep us posted!

I would at least ask for a video of it hot starting, or check that after a test drive when you go see it.

If it starts on a dime, after being hot, then you are PROBABLY in the clear.

Considering the owner put a K&N in there, he definitely isn't exceptionally knowledgeable, something to consider...

With that little mileage, you are probably fine if the car has appropriate real-world "behaviors".

I wouldnt really want to spend the money to get a couple hundred dollar test done on a car Im trying to off, even if I wasnt hiding something, so I do understand why that might happen.

Think of it this way, the compression test cost is not only piece of mind but also a bargaining chip in price negotiations. I wouldn't touch a 2011 R3 or a 2008 GT without a compression test, even if it had 3000 miles. Without the compression test, you have no idea of the health of the car. As Jazer said the K&N is another indication of poor choices in mods. The K&N lets too much "chit" in through the air intake system.

Awesome, thanks for the advice everyone. I'd heard the same about the K&N so I was happy to hear that he at least still has the stock airbox should I end up buying the car. With that said, I think I'll be sticking to my guns and making sure I get the engine checked out.

As a side note, I probably would be a lot less concerned about the compression test had I not just looked at a car last week that had 34,000 on her and appeared to be in great condition except for some minor vibration in the shifter. I got a compression test done just in case and it turned out the front rotor was bad.