my son's car overheated and had to be towed home. when i looked at it the dist cap was melted off, the oil pressure switch spews oil. Either the radiator or thermostat may have failed. I replaced the cap&rotor and tried to crank it but will will not turn over as if no spark. I only had an hour to work on it and decided we need a compression test to proceed. Any ideas? I hate to predict a new engine.

Welcome to the AF.

If the engine got hot enough to melt the distributor cap, you probably have no engine left. If you can get a consistent compression reading, you have hope, but that's a big if.

After a compression test, take off the head cover and see what the cams looks like. Also, the timing belt may have become useless. See if it is in good shape. Might have blown a radiator hose or heater hose.

If things look possible, change the engine oil and the rest of the engine rubber components (hoses, tubing, spark plug wires, all high-voltage ignition wires).

Be careful about how much money you spend on that engine before you figure out its internal condition.

Thank you for the welcome! yes, i'm trying to avoid spending money and finally need an engine. is there a market for 30+K miles engines for this car and if so what is a ball park price on them?

Here's one for $1000
http://www.asapmotors.com/used-toyota-engines-transmissions.htm

The 5S-FE is one of the most popular and reliable engines ever made. You can certainly find one. If I were you, I would make a thread in this forum asking specifically about reputable used engine sellers.

compression on #1 210, #2 203 and there is water or moisture in it. #3 & 4 having problems getting plug extensions off, they are breaking to pieces when pulling on them so have not been able to pull the plugs for compression test. removed the valve cover and the cams are turning. want to remove the head to see what is cracked head, block or gasket. Any input appreciated since I have not done this before.

Clean out the plug tubes (vacuum cleaner or compressed air) before you remove the plugs. Otherwise, all the crap from your fried plug wires will fall into your combustion chambers.