I agree with everything Justin minus the keep driving it idea. You were uncommonly lucky with your experience. Most of the time damage occurs from letting it go and continuing to drive. I would strongly suggest correcting the issue or parking the vehicle until repairs can be made. Continuing to drive and monitoring is not a good idea.

Quote Originally Posted by jmettee View Post
Check your hose clamps & hope for the best with just a few loose ones, but...

Likely a head gasket. I had this problem, more or less. I would have to keep "burping" the radiator & checking the coolant level frequently. What happens is compression pushes air into the cooling system at the top of the cylinder, which collects in the radiator. Since the air collects up there & expands more than the fluid, it pushes fluid out of the system to make room for the expanded air. The air also is what is holding pressure & is vented when you loosen the cap.

This is seemingly becoming more common. Keep an eye on both your oil & coolant for cross-contamination. It seems the top cylinder leak simply pushes combustion air into the cooling system, but not oil. If you're luck like I was, your coolant will end up smelling like used oil/exhaust gas, but not actually have an oil film/sludge (& vice verse, you won't have coolant in your oil). I drove mine this way & simply kept an eye on it for over a year - even drove to DCS on it (1200 mile round trip).

If you're not crossing fluids, you can just babysit the fluids & levels for a while & save up for an engine top-end rebuild to replace the gaskets. I chose to go with performance cams at the same time "while I was in there".