'79 244 DL ~300k miles. Tonight was relatively cold in my area. Above freezing, but enough to require a decent jacket while outside. While driving, I turned the heater on and off a few times. After parking, I noticed steam coming from under my hood. Popped the hood and immediately saw that my brake booster was covered in coolant. It was also spread across other places in the engine bay, but the brake booster seems to have gotten the most direct splash. Coolant level is very low. Fortunately, I always carry basic car/non-car emergency supplies in the trunk, so I filled up the reservoir, and changed plans to let me head straight home. Upon parking, steam again and the reservoir is very low. It was dark when I got home, but based on where the most steam was coming from, I suspect the heater hoses that go into the firewall. I also think my heater core may be going out - past few weeks the driver's side of the windshield fogs when the heater is on. What should I look out for/replace while I am rooting around my heating system? If the heater core is bad, I'll have the dash apart anyway so blower motor seems like an obvious choice. Based on records from PO, it got done in the early 2000s. I'm assuming the intake manifold needs to come off to get to the heater hoses, so intake manifold gasket too. Anything else? Also, anything else it could be? I will get a better look at where the coolant is going once it is light out, but any pointers on what to look at are appreciated.