I'm not familar with the 98 F150, but I'd be very careful with this one. Ford has basically 3 different (& somewhat confusing) coolant specifications. They are NOT made to be mix and matched. A call to a local dealer may be your best approach if the owners manual doesn't identify the coolant Spec number.
First, there is the "Premium" coolant, basically their conventional green (Prestone-like) coolant meeting Ford Spec ESE-M97B44-A.
Then there is a "Specialty Orange Coolant", some sort of ethylene glycol based, extended life coolant meeting WSS-M97B44-D specs.
Lastly, there is a newer "Premium Gold Engine Coolant", which is a yellow-colored, extended-life coolant meeting Spec WSS-M97B51-A1. This one is probably like Xerex G05 coolant, if not actually the G05 stuff sold under the Motorcraft name. Xerex will tell you this one is backward compatible with conventional green coolant applications, but Ford has not agreed with that idea yet.
Remember, I said "confusing"
Yes, Fords can be a POS to work on, but your coolant lines going to the oil filter are probably for the oil cooler. That's a good thing if you have a towing package on the truck.
Good luck.
[ April 20, 2004, 09:32 PM: Message edited by: Roger ]