Originally Posted by ImportConvert

No, you're running something thick as syrup and it doesn't lubricate as well, or pump NEARLY as well. In other words, you have more pressure at the pump and less up top and over the bearings.

No, you won't blow your car up the first time, but it's not a good habit at all. That is why many high-end cars have tach's that adapt to the running temp like the M series, etc.