[_hoodieboi_]

So my car is starting to overheat easily and the coolant reservoir is filling itself up. I'm planning to replace the gaskets on the engine and I believe this is the very first time it has gotten any heavy maintenance. the car has 227k miles on it. I'm like 99.99% sure pistons are going to be far from perfect but I wanted to see what I should expect and be careful of such as the bolts or breaking anything fragile.

 

[Mazda Carnage]

You will probably need to check the head and make sure it hasn't warped, never drive an engine that goes above temp, if coolant wasn't doing it's job in the block and head cylinder temps can leave pitting on the pistons but usually not on N/A tune.
Be gentle with the engine harness when moving it out of the way, once the you have the head of I recommend using a strong solvent degreasser (acetone, break cleaner, seafoam, thinner...) and spay it between the cylinder wall and pistons and move the pistons around the cylinder to clean the rings and ring lands of carbon and burnt oil, pull the drain plug and let it run out the pan (will clean any sludge from overheating in the pan), use a felpro head gasket and torque everything to spec in the right order and the engine will be better than it was when you got it.

 

[_hoodieboi_]

You will probably need to check the head and make sure it hasn't warped, never drive an engine that goes above temp, if coolant wasn't doing it's job in the block and head cylinder temps can leave pitting on the pistons but usually not on N/A tune.
Be gentle with the engine harness when moving it out of the way, once the you have the head of I recommend using a strong solvent degreasser (acetone, break cleaner, seafoam, thinner...) and spay it between the cylinder wall and pistons and move the pistons around the cylinder to clean the rings and ring lands of carbon and burnt oil, pull the drain plug and let it run out the pan (will clean any sludge from overheating in the pan), use a felpro head gasket and torque everything to spec in the right order and the engine will be better than it was when you got it.

I don't have the money to resurface the block and I don't have sufficient knowledge to do it myself but what will happen if I don't resurface the block and just apply the new head gasket

 

[Mazda Carnage]

I said nothing about resurfacing the block.
The head needs to be checked to make sure it hasn't warped.

If you use a new head gasket and a warped head, it wont clamp the head gasket properly and the head gasket will fail where the head is warped.