Yesterday we took our 2007 FEH (4WD) up a fairly steep rough road (jeep trail) near Olathe, CO. It involved some steep inclines and probably gained ~1000 feet. Since the vehicle is essentially new (2 weeks old), I didn't want to go too far and we stopped halfway up and hopped on mountain bikes. We turned it off and got ready for our bike ride. Someone noticed some serious dripping under the car. Coolant was POURING out. This was not some minor drip, but a stream of coolant. I didn't think I hit anything and was concerned a hose fell off.

With the hood open, it was easy to tell it was the engine's coolant that was pouring out: the reservior was almost empty. When we released the cap, however, the tank filled halfway up and the dripping stopped! A quick inspection showed that all the hoses were intact. This was perplexing. There were no messages from the onboard computer.

We did get the vehicle back down and parked it over night. In the morning we filled the coolant back up to the line (50/50 per manual). In a few minutes what we put in was gone! So we added more. This time it stayed. Today we drove back to Colorado Springs and had no problems.

My questions to the group: has anyone seen this? Does anyone have a hypothesis for why it happened?

My guess is this: going slowly up the rocky road caused the engine to heat up. It was pretty steep and a lot of work to get up as far as we did. The increased heat and decreased ambient pressure (~7000 feet elev) causes pressure to build up in the coolent system. The pressure got so high, the coolant slipped out one of the hose seals. The coolant was doing its job (kept the engine cool) and thus the onboard computer didn't register it as a warning. When we opened the cap, the pressure equalized and backfilled the reservior. With things stable, the coolant system is now back in action.

Thanks for any thoughts. I need to decide whether to bring it in right away or if it fixed itself.

ryan