transfer of the oil into the block itself. At higher revs, when the oil pressure kicks up, the OEM oil cooler begins working to cool the oil down. Your oil pressure gauge will indicate to you the most important element of the lubrication system, but a coolant temp gauge will tell you a more critical piece of information than an oil temp gauge will. But, nothing wrong with having both - it was just a suggestion to those based on my own opinion of what gauges should be paramount to others.