81 505 TD

[Guest]

My 81 505 TD has coolant leaking from under the manifold just below the

coolant tank. This started just after I filled up a month ago and I

have not driven it since. (I do have other cars to drive.) The symptoms

go like this: On the freeway at about 65mph I heard a bang like

something hit the underside of the car. I looked into the rearview mirror to

see a lot of white smoke that did not last long. Fearing a blown

engine I watched the gauges as I slowed down. I was about a mile from home

and the only gauge to move was the temp. That told me something in the

cooling had blown. I got home before the temp got into the red and

lifted the hood to try and see just what had happened. The only place I

could see any coolant was under the coolant reservoir and in top of the

turbo. I checked the hoses going to/from the firewall and found no

leaks.

My question is: Since the engine was running fine before this

happened, could this be a freeze plug that has rusted through? It has been

loosing coolant (about 2qts a month) for about a year before this

happened. I am not sure that I want to go to the trouble of replacing just one

freeze plug as I am not sure just where they ALL are.