Hello everyone, its been a while since I've posted. Haven't had any real issues. But now I have head scratcher! I recently had an opti-spark failure (no suprise there), after replacing it my coolant would disappear. Rad low enough to turn on "low coolant" warning light but reservoir was full. Pressure checked system found crack in rad side tank. Replaced Rad. After all that still losing coolant. Under pressure with tester losing about a pound every 15 min. There is no sign of a leak, carpet inside is dry, no sign of weep hole on pump leaking. The reservoir is full and the recovery system is bypass while testing. After multiple attempts to find the issue I concluded that the coolent must be entering into a cylinder, and changed the oil to confirm. There was no coolant in the pan eventhough I had about 2 quarts used in the testing. It's a 93 TA, rebuilt 13k miles ago all new accessory components including WP. Anyone have any ideas on how to further diagnose the problem? I don't really want to start throwing money at it, the heater hose alone is 200 bucks.