Ok so I went from having glow plug issues and two non working circulating heaters (http://www.thedieselgarage.com/forums/showthread.php?t=135401) to a massive coolant leak somewhere near the firewall on the passenger side. I'll post some pics here in a bit. 1994 7.3 IDI factory turbo. It's gushing when you step on the throttle and it's a steady stream at an idle (a quart in twenty minutes I'd say). The truck has sat parked in very cold weather for the last three weeks to a month without being plugged in. Before the cold snap I never had any issues with coolant leaking at all. I did have a tire place install a circulating heater and I'll take a photo of that as well, however that is not where the leak is, but that is a new variable. I haven't been able to start this truck since I dropped it off with them to have the circulating heater installed. After burning up a set of glow plugs, I finally got a new set in and got the truck fired up and, kaboom, she's gushing coolant. Any help trouble shooting would be greatly appreciated. I've had a blown head gasket in a 6.0 liter but that was more of a oh god look at all that white exhaust sort of a thing. I don't see any white exhaust at idle or when you step on it--a little black smoke when you stomp it but nothing abnormal. I saw a post somewhere somebody mentioned the EGR hose. I don't know what the EGR is, much less where it's located, nor what it does. ALl help is greatly appreciated as I'm suddenly up SH** creek without a paddle and never seem to have good luck with used trucks. lol, best to keep a good sense of humor about these things. Pics soon.