I had to startup a Bronco at about -28C with Valvoline Restore and Protect 5W-30 on the 8th. It had been sitting out in this for about 6 days as I had to make a business trip to Asia. The cranking was somewhat labored and it took a second or two longer than usual for the engine to start, but it did. We have it easy compared to Fairbanks (300 miles north) that was seeing -45C in this same time period. I should probably be using 0W oil but am dealing with it to see if this Valvoline Restore and Protect 5W-30 has any noticeable impact on the engine deposits I have observed. 4,000 miles in and not really. 5W is just viable for my local climate but the inland areas become off limits in winter without a block heater.
Another owner in our local Bronco group reported that he somehow lost 2/3rd of his oil and into limp mode on a 100 mile drive in -45C, even with the vehicle being on the block heater before starting the drive, I'm waiting to hear what the solution was, but he was on the Motorcraft 5W-30 blend.
Another owner in our local Bronco group reported that he somehow lost 2/3rd of his oil and into limp mode on a 100 mile drive in -45C, even with the vehicle being on the block heater before starting the drive, I'm waiting to hear what the solution was, but he was on the Motorcraft 5W-30 blend.