I was headed to school in the morning when my 04 mazdaspeed decided to stop giving power after popping and producing a plume of smoke cruzing at around 60-70 mph. I would assume it is the head gasket cracking, causing the coolant to pour into one of the cylinders. The car rolled to a stop remaining unresponsive to the gas or crank. I was wondering if anyone had insight on rebuilding the block before pulling the engine out myself. Does a rebuild over replacement sound like a possibility?

 

I'd guess timing belt.

 

Smoke? What colour smoke?

Get someone to turn it on the starter, and see if the cams are turning by looking down the oil cap opening. If cams turning the belt is ok, do a compression test. That will show a blown head gasket, or a holed piston. Check dipstick, black oil OK, creamy oil blown head gasket water in oil.. What is the level of coolant, is it up or down compared to usual. Have a look at the front of the engine - are the plastic coverings distorted/broken, any sign of a belt there where it should not be? When spinning the engine on the starter, note how it sounds - labouring like normal, or spinning easily/fast? The former suggests the belt is ok even without looking, the latter indicates broken belt, or serious loss of compression.

Do those basic checks, and let us know the results.

 

The smoke was white and the coolant evaporated immediately after the pop. There aren’t any visible shavings but I did have an issue with the water pump belt slipping and eventually snapping causing a similar issue a few months ago. The engine still turned on unlike this time, though. The oil looked fine with no visible distortion to the color. I still need to get it on a starter and check for fragmented belts once more as you are saying. I will get back to this when I have that information. Thank you.