2006 Mazda Miata Revival

Sometimes, the smallest mistakes lead to the biggest headaches. That was exactly the case with my brother's miata. A few months back, he called me from the side of the road... "I think it's dead". The previous owner bragged about installing an aluminum expansion tank on the cooling system - but in their infinite wisdom, they didn't use hose clamps. That oversight led to a slow coolant leak, an overheated engine, and—unsurprisingly—a blown head gasket.

Scoring a $400 Miata Motor

When I pulled the plugs and coolant came out, I decided to start searching for cheap used motors. After some searching, we tracked down a used 2.0L for just $400 in Austin, Texas. The owner had fried the clutch and was about to swap a 2.5L motor in. Unlike most mystery motors, we actually got to see this one running before it was pulled. It idled smoothly, had no strange noises, and didn't leak. Score!

Dropping the Subframe for the Swap

Miatas are tiny cars, which makes engine removal an interesting challenge. Instead of pulling the motor from the top (good luck separating the transmission), we opted to lift the car and drop the entire subframe out from underneath. It’s a bit of extra work but made the swap much smoother.

New Parts

Once the old motor was out, we took the opportunity to replace the clutch—because why not? The last thing we wanted was to drop the subframe again in a few months just to fix a worn-out one. That turned into a new flywheel, throwout bearing, pilot bearing, and a bunch of while you're in there gaskets. If you're doing this job, don't forget to replace the rear main and every coolant line seal. There were quite a few worn out O rings on this one after just 90,000 miles.

Fixed?

With everything buttoned up, fluids topped off, and a proper hose clamp installed this time, we fired up the new engine... And it billowed smoke :|

I started to worry about the $400 motor. The cooling system passed a leak test, and we saw it running flawlessly before. WTF?

That's when I remembered - the exhaust was FULL of coolant from the last motor's completely blown out head gasket. Even after sitting outside for a week, it still had coolant in it. A few minutes later, the smoke was gone. Phew!

One more miata back on the road. On that note, these NC's are hugely underrated! While the racers keep driving up NA/NB prices, these are readily available for $5k, far quieter and more comfortable to daily drive.