Chosen Solution

Hi all, So I’ve been having a recurring problem on my late 2011 MBP, which from googling seems somewhat common - but I can’t seem to resolve my specific problem. I am currently on High Sierra (10.13.5). Basically kernal_task spikes to 200-5000% -> fans spin up full -> my macbook obviously then acts sluggish for 5-10 seconds but sometimes longer. This coincides with what I think are incorrect temperature sensor readings, running TG Pro, (jumping from 50C to 100+ and then dropping back down). Now I understand that kernal_task is there for a whole load of reasons - and it is not the problem but a symptom, its purpose I believe in this case is that it thinks the laptop is overheating, so it blocks of cpu cycles to help stop the machine overheating. Things I have tried to remedy this situation (from suggestions on other topics): Reset PRAM and SMC Replace non-oem battery with original Clean fan and dust from machine Clean heatsink, cpu and reapply Thermal paste Clean Reinstall of OS 10.13.5 Running Diagnostics - all clear (except for battery warning, which has since been replaced) Running Apple Service Diagnostics software (both kinds) - All clear Run Etre check - Nothing that stands out as an issue Run TG Pro - Here I have seen temperatures with strange values and large spikes (despite TG Pro saying “temperature sensors appear to be normal” Additional Notes: I have an SSD in the old HDD slot. Running in safe mode I haven’t run into the problem or at least it didn’t occur in the couple of hours or so I tested it for. It still occurs on a cloned version of my OS running via usb My conclusion is probably that the sensor is bad and I likely need to replace the motherboard - but I’m hoping that there might still be a solution out there. Thanks

As for the kernal_task process. Thats the root process everything hangs off of. And you are correct its not the root issue, I’m suspecting you have a very basic issue. Bear with me as I explain… Since you upgraded your system to High Sierra you’re now using a new file system on your SSD drive! GUID/APFS whereas when you were running Sierra or older you were running GUID/Journaled (HFS+). APFS has issues running on SATA based drives! So I try not to run it on older Mac systems. But lets put that aside right now as you still have a hardware level issue that many Unibody MacBook Pro’s have and thats the HD SATA cable. Here we have seen in both the 13 & 15" models the rough surface of the aluminum uppercase wears the cable over time as well as the flexing of the corner folds breakdown the foil wires inside of the ribbon cable. In the 15" the plastic mid plane frame clips break and a good hit on the bottom cover can damage the cable as well. As a point of process I always replace the cable when I switch out a HD for a SSHD or SSD as these drives can encounter issues with a weaken cable as the data flows are higher through the cable. So here is the cable I would use: MacBook Pro 13" Unibody (Mid 2012) Hard Drive Cable and yes this is a 2012 cable! And here is the guide to follow: MacBook Pro 13" Unibody Late 2011 Hard Drive Cable Replacement In addition I would place some electricians tape across the upper case where the cable rests and not over crease the folds. The next thing here is the drive maybe slightly corrupted so I would make a fresh backup (TimeMachine) after installing the cable then reformatting the drive and restoring from the backup so no residual issues would pop up. Even still I would roll back to Sierra and hopefully by this falls release of Mojave this will be fixed.

Take a close look at the logic board where them crimped ends of the heat sink are and see if you can discern an oily type of stain on the board.

I have a MacBook Pro 13 early 2011 i7 with 8GB of DDR and a Samsung EVO 860 installed. It is running on APFS. It is fast and responsive with excellent scores on GeekBench. At startup the temp spikes to 95c and the fan runs fast. This occurs without or with SMC operating. After 20 seconds or so when loading is complete, the temp drops to 45-55C and as I type this the temp is showing 48c. Is this a HDD cable, heat sink or temp sensor issue?