I have a 2002 7.3 powerstroke that I bought 2 years ago. When I first got it it hardly started in the 20s unless it was plugged in. The oil used was Rotella T5 10W-30. The HEUI system requires good oil flow to the injectors to get them to fire. If the injectors hang up a bit till oil is flowing thru them real good--well then you'll be cranking for quite while and draining the batteries. The first winter I upsized the glow plug relay and put REV X in the oil. REV X is supposed to clean injectors and leave a lubricating film on them to aid in the dry starts on HEUIs. The two things together made a huge difference and it started pretty good after that even without being plugged in. The 2nd winter I again used the T5 but put 2 cans of Lubro Moly MOS2 in the oil instead of REV X. Its cheaper and I'm thinking there may be more overall benefits and less risk. I think REV X uses a lot of boron. I'm not big on oil additives but I am big on reliable ignition in cold weather without long cranking or requiring a plug in. The truck is a hunting truck so it needs to start reliably in cold weather without a plug in. At home its always plugged in to save wear on the engine and batteries. But again when out hunting it needs to start in cold weather with no difficulty to be reliable. So last winter I put the moly in the oil and every time I'm out hunting and it has a cold start it fires right off. One night in January they were calling for negative temps so I unplugged it to see if it would start the next morning. It was -4 F next morning -- I cycled the glow plugs twice and turned it over. It fired right away and idled smoothly till warmed enough to drive. Again I'm not a fan of additives, but this MOS2 really seems to help the HEUI on cold starts. Is there any possible downside to running 2 cans of MOS2 in the oil thru the winter? I realize this is not a tested combo, but it really seems to work well in the winter. Thoughts?