My 87 7MGTE has an ongoing issue with recovered coolant in overflow tank not returning to radiator when temps cool down. After driving, the overflow tank level will go from between "Low" & "High" levels to approx. 1.5" above the "High" level. When cooled down, overflow tank level stays the same and the level in radiator is down, so I have to take coolant from overflow tank to fill up radiator. When doing so I notice small coolant loss of approx. 1/4 of a quart for day's worth of driving (35 miles or so). The car runs fine and doesn't overheat (gauge shows needle in the middle when warmed up and during driving). Although idle will go down to 550RPM at times especially while driving in stop & go traffice.
From reading other posts I've read here, there's a good chance my engine has a BHG.
So, I did a dry compression test (twice) and I think the numbers are okay?: #1=152psi, #2=145psi, #3=142psi, #4=135psi, #5=140psi, #6=150psi.
If I have a BHG, shouldn't I get lower compression readings?
I'm assuming that since there are no signs of external coolant leaks, leak is internal (thru HG?) so when engine cools vacuum is not created to recover coolant from overflow tank?