I have an 87 Bronco II - 2.9L. It runs fine on local runs, but when i run on the expressway after about 15 miles it starts ticking like a time bomb. If i get off the exit, the ticking goes away within a mile. Only ticks when running on the expressways for extended mileage with speeds above 60. I have replaced the oil pump, thought the valves might not be releasing and got me up to the 15 miles. You started ticking at 5-7 miles before the oil pump. Any suggestions???

 

Put a mechanical oil pressure gauge on it and see what it does.

 

I did that before the pump. It runs at 18 when idle and steady at 42 to 44 when on the expressway. No drop in pressure when it starts ticking.

 

Cam bearings are shot, common problem on 2.9s.........unable to keep the top end lubed at constant highway RPMs.

 

Quick fix is changing motor oil weight to 10-40. A lighter oil just doesn't do the job. Long term you prob want to rebuild the heads.