Hey guys,

Just returned from my mechanic. 1997 4.2L F150 blowing white smoke. 1st diagnosis was blown head gasket which I kinda already suspected. Then at 2000 rpm, a pretty steady knock in the engine. Didn't hear it a lower RPM's. Options? Option 1 - Replace headgasket and pray that motor doesn't get worse. Option 2 - Salvage motor around $2k installed. Option 3 - Rebuilt motor with 3/36 warranty for $4k. Any help out there would be appreciated.

Thanks
Stephen

 

It all depends on the rest of the truck. Did you do ALL scheduled maintenance? Tranny fluid, regular oil changes, rear end fluid. I mean if the seats are all ripped up, the brakes are bad, leaking fluids, a big dent in the box, the cab mounts are rusty, then throw it away. If you took good care of everything, and you know all else is fine with the truck, then get the new motor. I believe you can get a new Jasper motor installed for around the same price as that rebuilt.
Or, if the truck is OK, and your not sure not sure how much life is left in the tranny, rear end, then do the head gaskets and hope for the best.

 

Are you sure its a head gasket? Are you sure its not the lower intake gaskets that are bad? Did your engine over heat? If so,i'de say its a head gasket.Otherwise,I think your lower intake gaskets have failed and its burning the coolant leaking into the cylinder/cylinders.
If its knocking then i'de say its time for a new engine.

 

My truck has 156K miles on it right now. At 140K, the truck wouldnt start and produced a terrible knocking sound. We had to get a new 2003 4.2L V6, so now its a 8 year old truck with a 1 year old engine. We found that water leaked into one of the cylinder heads and cracked the block. But for $4K we got a new engine!

 

I just pulled the 4.2 out of my 98 F-150 SC yesterday for the same thing. I had water in #1 cylinder. and a knock in the motor. What happened was it hydrolocked and bent the rod. By this it let the piston come down further in the cylinder and let the couter weight of the crankshaft hit the bottom of the piston each time it came around. I will have to relace the piston, rod, and the engine will be fine to rebuild. But i cracked the intake and will have to find one. If you had water in your motor and started and run it beware it could have bent a rod. Water does not compress well. good luck.