Three problems related to loud engine noise have been reported for the 1998 Ford F-150. The most recently reported issues are listed below.
The contact owns a 1998 Ford F-150. The contact stated that the vehicle stalled without warning, accompanied by a loud noise from under the hood. The vehicle was taken to a mechanic for inspection where the contact was advised that the spark plugs did not have enough thread and separated. The vehicle was repaired. The manufacturer was made aware of the failure. The failure mileage was 100,000 and the current mileage was 152,000.
Ford f150 1998 4wd 4. 2l engine 102,0000 miles - when starting truck engine it would run rough then smooth out. Today I heard a loud pop sound. Now it doesn't start at all. After checking several web sites I realized my trouble is not unique. Looked around the internet but never found a recall notice from Ford relating to this issue. Further research seems to imply a major defect that Ford knew about from close to the beginning of manufacturing which they never have done anything about. According to a couple of web forum sites, Ford put out two technical bulletins to their service people but not to the end users/buyers (TSB #99-20-7) (follow up TSB #99b209) that pretty much admitted there was a fault with a gasket and could result in engine failure, as mine seems to have done. The resolution is for the engine to be replaced. Ford should be made to stand behind their faulty manufacturing & fix their errors.
Mechanic cannot determine causes of loud noises when steering after engine is warm.