99 Deville, Coolant Disappears??
The other day I and three others started a small trip. I checked the fluids before I left - toping off the coolant. It has been slowly loosing coolant for sometime now. My mechanic can't find anthing wrong.
It was in the low nighties, the air was on, life was good. we got around 30 miles and the display message said that it was overheating, then the AC was turning off, then turning on 'idle'. I idled to a jiffy lube, the coolant was bone dry. We found that the cap wasn't holding pressure because some pieces of rubber were missing. The only thing they had was a '16' (instead of a 15) - they said it would be ok. (my mechanic concurred later). Thinking that was the problem, got down the road around 20 miles and it was bone dry again. I had it towed to my mechanic.
They did a 'Block Test (chemical test), Cylinder Leakage Test, put it under pressure and looked for internal and external cooling system leaks They let it sit running for a couple of hours in the sun in the middle of the day to see if they could get a clue. Nothing.
They had also put a couple of bottles of 'cactus juice' something or other, to plug potential cracks in either the engine
block or heads (can't recall which).
Any ideas, short of trading it in for something that doesn't have a northstar engine?