hello guys , i dont own an f-150 but i own two fords , a 01 crown vic and a 93 thunderbird sc. im posting this for my father in law.

he has a 1998 f150 with the 4.2 engine in it. it has 100,000 miles . today when he started it there was a loud tapping noise from the engine , it runs great , doesnt shake and the noise goes faster when you accelerate the car.

a mechanic came today and ran codes , i wasnt there so i didnt see the codes , i know they were p03 something which tells me a missfire and then he said they said p1 or p2 after the code. he told my father in law the engine was no good. i doubt it.

sounds like a rocker arm loose.. you could really hear it in the front part of the engine . what could it be ???

thanks.. sry for the long post

 

Maybe a bad bearing somewhere in the motor..hopefully not, but thats what it sounds like to me.

 

thanks for the quick answer.. what about lifters ?? we just seafomed the engine two weeks ago and i dont think he changed his oil yet

 

also could hear tapping in the oil pan

 

The only thing i could tell you now is since you hear tapping from the oil pan, it might be a bad crank bearing. Other than that i dont know what else to tell you, soon someone more knowledgable should be here to help you.

 

ya i just read that too in the forums, sucks.

thanks for helping me man !

 

No problem, it weird how its knocking at only 100,000 miles.
Mine has over 216,000 on it and mine has a very faint knock in it(or maybe small exhaust leak?), but either way i dont care, i plan on keeping my truck till it blows!

 

ya man his truck is really clean, no leaks or anything i told him to pour a bottle of marvel mystery oil tomorrow just in case .

 

I doubt it will help, but have him change his oil to get the seafoam out. What are the temps where you live, and what weight oil does he use?

 

Beware the usual hydrolock common on pre-2000 4.2s!
Search this forum for the tales of woe.

 

nevermind he changed his oil last friday, im in miami so warm temps but its been in the 70's lately, he doesnt know what weight they used.

hydrolock like bad headgaskets ? spark plugs were dry and no coolant loss. no white smoke nor bubbles

 

umm i don't wanna say something stupid but you sure its not an exhaust leak? i have a 98 f-150 with a 4.2 it currently has 150000 on it. at about 120000 a pipe coming off the passenger side mannifold rotted out and caused an exhaust leak, it sounded like a horrendous knock. but i inspected it and new it was an exhaust leak, the truck ran fine. so i fixed it, at 135000 the driver side manifold cracked and made the same noise and i replaced that and it took care of it. you could very well have a serious motor problem but this is just some things that have happened to my 4.2. also at 85000 my number six spark plug rotted in half and caused the truck to run like **** till i changed the plugs. he may have a rotted out plug. i hope this helps you, other than that the running condition of my 4.2 has been flawless for 10 years.

 

the plugs and wires have like 100 miles on them , and no i didnt check for an exhaust leak , thanks for the heads up i will check that next time.

 

I just got done going through the same problem with 98 5.4 litre. Hydrolic timing chain tensioner was the problem. you have explained every single problem I went through with my truck. about a six houre job did it myself.

 

I have a 98 4.2l manual and it has 286,000 miles on it. It has started to knock right behind the driver side tire, but once I shift into 3rd gear going down the road it leaves. Some days it starts without the noise. It drinks radiator fluid like sponge, and I just did a oil change and it was dark black. I have read where these engines have been plagued with the timing gasket leaking fluid into the oil and tearing **** up! I have a 04 engine off a wacked truck ready to replace the 98 but before I jump into changing engines, can anybody tell me this is something else? I don't have a lot of $ to do a lot.