After working for awhile, the screen goes black then unit powers off.

Hi everyone,

Mid 2014 model Retina.

Originally determined that the unit was likely going into a thermal shutdown. So I purchased the kit that replaces the thermal paste on the CPU and GPU. It has improved, I can run longer now (10 - 12 minutes) before a random shutdown. I installed hwmonitor and have been watching sudden temperature spikes and then the shutdown occurs. I installed SMCFanControl and now I’m able to keep the fans running on high speed, which prevents this from happening.

I did the thermal paste twice to ensure that I did it correctly. The first time around I used the spread method. The second time I used the vertical stripe of thermal paste. Both times I used a liberal amount of cleaning and condition fluid and ensured that it was dry and lint free before reinstalling the heatsink bar.

Should I try to replace the heatsink bar next?

What, if anything, else can I try to try to remedy this problem?

It’s worth noting that I can make this happen on a fresh installation of MacOS Mojave.