As a young boy I grew up in a large logging community. My father owned the only Service Station in 20 miles of the largest town. We serviced about a 100 Log Trucks, it was common to see a can of ether or starting fluid in a Diesel Log Truck. Loggers kept alot of it in there service trucks to start there Logging Skidders. We used it to some degree, but not much. My father always told me that too much could "lock up" the engine or "blow it up", besides being "harmful" to you. We normally just used our Block Heaters in our Ford F-250's at our shop. I've seen too much Ether blown into the air intakes, and the engines start "violently". The Block Heaters are the safer way to start a "Cold" Diesel engine. If that's not helping you've got more problems, such as the "glow plugs". I've had my 300 SDL for 2 years and have never blown any starting fluid or ether into it and I sure don't plan on it.