Warning
Remember that the radiator fan (located at the front of the engine compartment, behind the radiator) may start automatically some after the engine has been switched off.
Always have the engine cleaned by a workshop - an authorised Volvo workshop is recommended. There is a risk of fire if the engine is hot.
Warning
The ignition system works at a very high and hazardous voltage. The car's electrical system must always be in ignition position 0 when work is being performed in the engine compartment.
Do not touch the spark plugs or ignition coil when the car's electrical system is in ignition position II or when the engine is hot.