I have a 98 F150 with the 4.6.
Sunday I began to hear a grinding like noise right as the truck begins to idle.

It has 260k miles on it and the first thing I thought was timing chains.

I work at a GM shop, so, the techs here know nothing of Ford motors.

One says it sounds like a timing chain, the other says the sound is coming more from the center of the motor.

I need to know if anyone else has had a timing chain issue, and what exactly happend, what it sounded like and where the noise was coming from.

If it is the timing chains, could it maybe sound to some like its coming from the center of the motor?

 

You have to pin-point.

Stethoscope the front cover. That should tell you right away. Just use a long metal piece of round stock or screw-driver, - works every time.

 

Did just that. You can hear the noise thru the cover, just seems louder (to some) towards the top center of the motor.

 

Does it run okay? You may have lost something on top of the head, - iduno what it could be that would sound like a chain tho ??? Unless your running Bosch plugs and one has fell apart inside the cylinder. Don't laugh, that's what those plugs do...

 

i remember seeing those pictures, glad i saw that before the bosch i had in mine started destroying my motor. after seeing those pictures i changed mine the next day

 

I always use all Motorcraft parts.
For about two years, when you come to a stop light, it seems to idle kinda rough, almost like a miss, but plenty of engine power. Now this noise has started.
I am beginning to believe that possibly the rough idle was caused by sloppy chains retarding the timing slightly, and now the noise is the beginning of the timing guides tensioners coming apart.
Just a gut feeling. But the guys here that work on trucks, cant seem to pinpoint exactly where the noise is coming from.

 

Try removing the serpetine belt and then run the engine. If the noise is gone then check the belt tensioner, front cover pulleys, alternator, anything that the belt turns. Sometimes a fin will break off the water pump impeller and rattle around behind the pump. From your discription and the high miles on your engine I would tend to think it is the chain tensioners or guides. Anyway removing the belt would be my first course of action on this. If the noise is still there with belt removed then it's time to remove the cam covers and front cover. Good luck.

 

Removed the belt. Noise still there.

If I remove the timing cover, will there still be tension on the chains so I can see if there is alot of play in them?

 

You can actually check for play by removing just the cam covers. Once removed you can see the chains below the cam timing gear. If they are loose (floppy) then you probably have defective chain tensioner/s or blocked oil supply holes behind the tensioner/s.

 

Can anyone tell me if I can reuse any of the gaskets when I do the timing chain or will I need both valve cover gaskets and timing cover gaskets?

 

They can be used over if you are real careful when removing the covers. But don't remove the gaskets from the covers or you may not get them back in the cam cover groove. Remember to reinstall a dab of black RTV at the two spots on each cam cover and the 6 spots on the front cover. Probably be best to just go buy new gaskets at the dealer.

 

Well. Got the front cover off and besides a little wear to the guides, chain is not loose and everything looks good.
Going to replace tensioners, guides and chains anyway, but just by looking, does not look as any of it could cause the noise I am hearing.

 

You pulled the front cover ??? To late now I guess.

 

Yes. But now I think I have the noise and the rough idle figured out.

The intake manifold tuning valve, I believe that may be the culprit.

 

That's good