compression test with warm engine

[Brandon505]

you're supposed to let an engine cool before removing spark plugs (especially with aluminum heads), so how can you do a proper compression test where you're supposed to warm the engine first?

[Chris.howels]

There are several precaution measure, that you have to take
1. clean the spark plugs from any dirt, while the engine is cold
2. disable fuel and ignition systems before removing the sparks
3. put on some gloves to prevent getting skin burns
4. remove the sparks plugs very carefully, do not remove them if they offer resistance after turning it more than one half a turn

[DeltaP]

On a cold engine loosen the plugs 1/2 turn and blow out any dirt around them with compressed air. Snug 'em back up and warm up the engine. It doesn't have to be hot. Then remove them all with hand tools only. Disable spark and perform compression test with throttle wide open.
Unless it's a Ford Triton engine... Several of them will break anyway.