Here's the scoop on my tale of woe. I had one of those mysterious coolant leaks under the thermostat. The short version of the story is I had a small crack in the head. I spoke with FoMoCo and a local service manager. The manger said that if the coolant is not changed and flushed regularly (every year or 2) that it turns acidic with the help of the grounds that are tied to the motor. This, with cavitation under the thermostat, erodes the aluminum and eats it away.

Second part of the story is I am fonder of aftermarket gaskets then facotry. When the year; model; and engine is entered in the parts look up it returns a set of gaskets that does not match the heads. A visit to the parts counter while at the dealer revealed they had a difficult time matching up their own numbers. Eventually find that they are listed as 5.4 heads rather then the sticker 4.6 and the head changed after build dates of 7/20/97.

For What its worth: I am not a molecular chemist, but will be changing coolant and flushing the block regularly. Also, when buying intake gaskets claim the motor is a 5.4 and know your bulid date. The change in gaskets show up for 5.4 but not 4.6. Lastly, hope I have been living right and the Quick Steel epoxy putty holds.

 

Good advice. Thanks for the info.

I've been having the coolant flushed and changed every two years ever since I had an '87. Had two heater cores fail all because I didn't change the coolant every two years.

 

I hope to save someone else the headaches I had.

I bought this truck used and am now finding out why the previous owner sold it.

Ufortunately you can't get a service history on these trucks. Everything I took off was Motorcraft and it appears the intake has been off before.

Oh well, I am going to drive this thing until I get my 72 back on the road with iron heads and room to work on it.