http://forums.treemedia.com/fb/showthread.php?t=224

My 98 F150 recently acted like it had a dead battery when I went to start it. I bought a new one and as soon as it started there was a terrible knocking
and white smoke coming out the exhaust. Had run perfect when shut off night before.
Long story short it is in the shop getting a min. $3000 longblock. The 96-97-98s are the ones to watch. Ford put out a recall on the 96-97 models for faulty lower intake manifold gaskets. Coolant leaks into a cylinder and when the piston is on compression stroke it will not compress coolant as it can gas/air mixture, resulting in a bent or broke rod. The recall didn't reach many owners and some that it did had the gaskets replaced but engine damage had already occurred. Ford is so aware of this problem that they made the decision at whatever point that they were not going to replace that many engines so they did not include the 98s in the recall even though they too have the same gaskets as the 96-97s got at plants in Kansas City, MO, Norfolk, VA, and Toronto, CAN.
The link above is statements from disgruntled owners and some advice on recourse. If you own one of these lemons beware. I am not here to bash Ford or create a who is the best motor vehicle company. Also I am not one
to read something on the internet and take it as gospel and get on the bandwagon. My truck died-then I found this out.
Classic symptoms are:sudden sluggish/no start
knocking
white smoke
coolant consumption
white goo under oil fill cap
If anyone needs more info PM me. I have the TSB #on the recall and can
relate my experience contacting Ford and also the NTSA.
Jeff