well here goes for first tiime.......

Had cyl head gasket replaced..both and now I can idle car all day with heater working and no overheating or water loss but when I travel say 20 miles at med speed ie 40/50 miles it over heats with big coolong system pressure........ release, cool and add more water/anti freeze mix all well for similar time.

Is this the gasket again..........

cooling system pressure test at 14 psi will hold for 30 mns with only about 1 psi drop, longer time no further drop

Compression test shown 105 to 110 psi on all cylinders..........

Spark plugs all showing same light brown colouring......


I am dreading another mass of money on this only to find same problem......

Any ideas

Should say prev owner must have run it without antifreeze as a lot of contaminants in system ie rust particles....... but with cleaner and in line filter this has cleared and no issues here.....this was done before issues.

 

Check to be sure the water pump is not leaking.