Is There a Better Sight than This

When you have been worried over the last few days that your loosing about 1" of coolant from the top of the radiator every 6 to 8 hours, even when cold, is there a better site than this.

I could not find out where it was going, if any where. Checked the compression, checked inside the cylinders, checked the sump.

After concluding the problem was heading towards another strip down, as a last resort I took it for a drive to get it hot and the plan was to re torque the head from 60 to 65 lbs, which I can do now with new studs.

During the drive I noticed the motometer temperature reading was very erratic, dropping quite low at road speed,. then on idle back up again. I diagnosed (guessed actually) that the coolant level was temporarily dropping below the motometer sender.

Turned out to be air in the system, probably displacing about half a pint of coolant. When the engine was hot, the coolant level would be high indicating all was well, then when cold the level would drop ever so slowly. Even though the system is a lot slower to fill since the thermostat was fitted, I have never come across this before, and having recently changed the head, you always think the worse.

One more top up and all has been well since then. For those who may be wondering why I run the radiator coolant level to the very top, its because I have an overflow tank fitted.