The heat sink is now on the motors. I don't think the 4 in 1 is an overheat problem. We know the green and red blinking lights happens but when it happens is the key. When I used the bad 4 in 1 the light would be green on take off maybe 1/2 throttle the red light would come on than green than red back in forth on a straight run of 20 feet about 6 times one way and 6 times back. This is using a full charged battery. With the new 4 in one it takes off on green may blink red than stays green, unless you really push during the flight, for the remainder of the flight. Time difference is 3 minutes to 11.5 minutes.We should just keep an open mind to this and see if its the way you can tell the 4 in 1 is failing.