Like Dan says, we have to be careful adding telltales, and consider the effects they will have on proper cooling system operation. That all begins with a good understanding of the cooling water flow through the particular engine you are working on. I am really tired of all the “online experts” going on about systems they don’t really know everything about. The conventional OMC method of tapping into the exhaust manifold is far from perfect, but tapping farther down the cooling system can show a telltale flow that is inconsistent, or hot, which is going to create problems with thinking there is a problem, when there isn’t one.
In Amuller’s case, I think Pappy’s advice about a dash mounted water pressure gage makes the most sense, except that I don’t think he has his telltale tapped into the exhaust manifold. So, it is hard to know what pressure readings are to be considered normal…..
And, unfortunately, many cooling issues occur instantaneously and at higher RPMs, so chances aren’t good that you will be looking at a telltale or gage when the issue occurs. You only look at the telltale or gage once the engine overheats and falters, which is usually too late.
