Cover the pistons with something. Plastic, aluminum foil, etc. Just make sure that you limit as much crap falling on them as possible. There's no way to 100% prevent stuff from getting in the water jackets or other holes when you sand the block. That's why you use compressed air after you're done sanding it and then after it's all back together, you do a cooling system flush along with an oil and filter change after running the car for a while to check for leaks. You have no leaks? Great. I'd run it for about a half hour, make sure everythings up to temp and then let it cool, check the torque on everthing I took loose and then do an engine oil and filter change along with a cooling system flush. New oil and filter, new anti-freeze and you're good to go. You can check the head for warpage by simply using a straight flat edged ruler or anything else you know if straight. Take a flashlight and shine it on one side of the ruler and then the other and look for light coming through any gaps. Of course, the ruler is standing sideways, not flat. If you see any gaps, then you'll need to take it to a machine shop and have it milled. It sounds like a lot of work, but it's not really that bad. It just takes some time and effort, and I'm guessing you're not a lazy man that rushes through things. Keep in mind that if the head has to be milled, you'll be at the mercy of the machine shop and their time table. Make arrangements for transportation, just in case you have to leave it for a few days.

 

I'm not as concerned about head warping or prep as Rube is, although it is better to be safe then sorry. The method used to check for warping with a straight edge works well, I've used it many of time. Getting crud off the top of the block and the head surface is valid though and I have been known to go after things with a rotary wire wheel chucked into a drill motor to do it with. I use rags soaked with oil stuffed into the cylinder holes to keep crud out with. A slight spray of WD-40 works well and if you use enough rags when you start cleaning up, any crud is going to be stuck to them and come out with the rags. A place to use old T shirts that seem to manage to get used up working in the garage around my house. (Don't tell, I think Valerie is looking for one of hers that just might have gotten collected into the stash) An old school method of getting the head reasonably flat if needed was to use a big "Bastard" file and go after the head with feeling. Not needed too often but has been known to have been used. When the situations demanded that approach. Unless the engine work was dictated by overheating, which has lead to leakage due to blown gaskets, head warpage is generally not an issue.
Although I had to deal with that on a Mitsubishi engine a number of years ago, with an overhead cam and it blew a gasket had an oil leak due to warpage. (That confused me until it dawned on me the overhead cam needed oiling and the only way that could happen was an oil hole through the block, gasket and into the head start leaking out the gasket to warpage.
Through a recommendation from an accomplished mechanic I put the head back on with an Air Gun Wrench set on "Stun" and carefully followed the head bolt sequence and forced the head flat. The thing had almost 300,000 miles on it at the time and I found out by accident about 2 years after I sold it the thing was still running.
Good luck!

 

there is a plug at the bottom of the water pump which will drain the water very well along with contaminants then rinse it plug back in and go and I may check with you about a Japanese maple

 

I murdered two jap maples accidentally by over watering, easy to do with a sprinkler system and rich, poorly draining topsoil

My thumbs only turn green from infections.

 

Buy the whole kit, take your time, use new studs, and i like pb blaster but I have never tried what you mentioned so I cannot compare. PB blaster reeks to hell but does its job.

I had to spray twice a day for 2 days to get the lower control arm nuts/bolts to separate after 13 years of riding on the original struts. MF getting them loose, rest of job was straight forward.

90's Cavalier w 400K+ miles? WTF? Those things unpredictably imploded when fully maintained. You must have gotten one with absolutely ZERO marginal internal engine parts.

Go GM!!! GFY for running Saturn into the ground on purpose.

Me---opinionated? Naaahhhhh.

_____________

We all know you can do this project.

1) Plan your downtime, then multiply by 2 as you've never done this before. (By the time you're done you'll be able to do one in less than 1/2 the time, which is ironic, since you don't want to ever have to do this again)

2) TAKE YOUR TIME. If something feels stuck/binding and won't give, applying excessive force will either break it loose or break it. Be cautious with head bolts as you do not want to have to drill those out.. I'm not trying to scare you ---just lending guidance --it's 14 years old......

_____________________

On a side note that actually isn't a side note, how did you arrive at the conclusion that the head gasket requires replacement? White smoke out tailpipe? Oil/water milkshake? incriminating compression test results? The fact that you said it seemed to stop leaking is somewhat kinda alot perplexing to me. I know crap can reseal gaskets but .... Again, I'm not trying to give you the 8th degree, I'm trying to ensure you're on the right path to solve what ills your ride.

You might have posted it in a different thread I haven't caught up on yet. If so, my apologies.

 

My $.02: I've got what I'm pretty sure is a blown head gasket on my car right now. In Aviation, we call this opportunity maintenance. if I'm in there doing this anyway, why wouldn't I go ahead and change these other seals and gaskets that are probably living on borrowed time anyway. If you fix one leak, the stuff finds the next weak link and comes out there. I have the motor on its way out, so before I spend all that time putting it back together, I'm going to make sure, to the best of my ability, that it will be a long time before I need to take it out again. Mine is getting new everything. Full master rebuild kit. That said, I'm open to suggestions for a quality kit and a quality vendor.