Part way through the Interlagos race, the team feared that an engine failure was imminent, but adjustments by the HPP engineers and by the driver ensured that it made to the chequered flag.
The team has since made some changes to the suspect unit – outside the parameters restricted by the FIA regulations – and Hamilton is running it in Abu Dhabi in Friday practice.
After the second session, the data will be reviewed and the team will make a call on whether he needs to take new elements.
“The problem in Brazil was caused by a failure in the variable inlet system that caused unstable combustion,” said a Mercedes spokesman.
“Engine settings were changed to contain the risk of failure and maximise performance during the race.
“We have made hardware changes outside the sealed perimeter and we are running that engine (PU3) today. Data will be reviewed after FP2 to make sure all is okay.”
Valtteri Bottas, who like Hamilton is using an engine this weekend that has done a lot of miles, remains confident that the team will still have good performance.
“We are both sticking with the old engines that we used in Brazil,” said the Finn. “At least on Friday when we will check if everything is OK. At the moment everything looks fine, we should be able to do that, but we can confirm that during Friday.
“We are quite confident. Of course it is not the same as having brand new engines, but I am sure we are not the only ones at the end of the year running quite old engines.”