From GMM
McLaren has changed Heikki Kovalainen's Mercedes engine ahead of Saturday and Sunday's action in Singapore.
The German engine manufacturer's chief Norbert Haug explained ahead of final free practice at 7pm local time that the move is precautionary.
"We saw a little bit of usage in the engine," Mercedes' motor sport president said. "If there was not a 'joker' engine change, we would not have done anything.
"It's a critical time of the season and if we have it available (we should use it)."
Championship leader Lewis Hamilton is still able to change his engine without penalty in 2008, with new rules allowing one unscheduled switch before ten-place grid sanctions apply.
McLaren has changed Heikki Kovalainen's Mercedes engine ahead of Saturday and Sunday's action in Singapore.
The German engine manufacturer's chief Norbert Haug explained ahead of final free practice at 7pm local time that the move is precautionary.
"We saw a little bit of usage in the engine," Mercedes' motor sport president said. "If there was not a 'joker' engine change, we would not have done anything.
"It's a critical time of the season and if we have it available (we should use it)."
Championship leader Lewis Hamilton is still able to change his engine without penalty in 2008, with new rules allowing one unscheduled switch before ten-place grid sanctions apply.