White spark plugs

[TGPilot]

You can do a pressure test on your cooling system and/or compression test on your cylinders.

Cooling system requires the hand-held pump connected where the twist off pressure cap is.

For cylinders you need a pressure gauage on a long hose with the appropriate plug threads to thread it on. Crank the engine with no spark to any of the cylinders (you don't want to start it) for 3 or 4 seconds. Let it sit for 1/2 hour and see how much pressure you lose.