So removing a spark plug from a hot engine is a bad thing to do. I never knew that.
The hotter a metal gets the softer it is and the weaker any threads are, which means when an engine is hot you never ever remove sparkplugs. It also expands when hot which can cause other problems.
When I had one of the humbers i was in the habit of pulling number 1 spark plug to see the engine condition. I once made the mistake of doing that while the motor (alloy head) was hot. Put it back... no problem. That was until I was taking my then partner and our daughter to a naming ceremony near oxford.
The engine started to sound strange, and then as I accelerated it started making one **** of a racket. pulled over and opened the bonnet and there was a pretty blue flashing thing where something of that nature shouldnt be (it was dark at the time). The engine had thrown out the spark plug!. I shut the engine off and replaced it gingerly - and we got to where we were going..
Next morning I rechecked the motor and that the plug was tight - and saw a nice image of the spark plug threads on the fuel line coming from the fuel tank!!! the plug had come to rest on the fuel line and had been busy melting its way through it....
Jemma xx