I have a '91 F-150 with the 4.9L and manual transmission. I'm getting a "ticking" noise from the engine, and need some help with the diagnosis.

I don't hear the noise at idle, but can hear it when revving the engine. It gets louder and faster as rpms increase, and then goes away when shifting gears. I hear it primarily in 1st, 2nd, and 3rd gear. I don't hear it in 4th and 5th gear but that might be because the road/wind noise drowns it out.

It is a ticking noise, not a knocking noise. It sounds like it is coming from the top and back of the motor.

Any thoughts?

 

probaly a lifter, my buddys is bad. he has been driving like that forever. If you got a weekend off from work you can have it replaced. just learn about it a little bit more, and you will be ok.

 

Yup, sounds like lifter tap. Keep up on oil changes and dont hot rod/abuse that truck, and it will still probably last forever like that.

 

mines making that noise too i had a guy i work with that used to be a ford tech listen to it he said a lifter too he told me to run some atf in it for a few minutes to free it up then drain and change the oil and filter my side cover casket is leaking so i figure ill check it out when im in there

 

Try a thicker oil on the next change and see if that diminishes the sound, it's usually caused by oil starvation of the upper part of the engine (oil is getting there, it's just that it doesn't have enough pressure).

 

Mine's been ticking for years. Truck still runs good.

 

Is it a tick or a ping? Bad timing and poor fuel will cause pinging under load.

 

It's definitely not a "ping". I was thinking it was probably lifters or valves. We'll start with flushing the engine and an oil/filter change with heavier oil and see if that helps.

I appreciate all the responses.

 

I will also add that mine has had the lifter tick for the last 40K and she still runs like a dream (other than the ticking of course). as long as your not hauling all the time and putting the engine under strain i really wouldn't worry about it...

 

Got to thinking about this last night, and remembered a problem my I 6 had, may be whats happening to you also.
The A.I.R. Pipe that runs along the valve cover is a poorly designed part, and is prone to vibrating apart, causing major exhaust leaks. If only one of the injection ports broke apart, It could cause a tick, but one that would sound like an exhaust leak. No idea if this is your problem, but its easy enough to check if the pipe is leaking. With the engine cold, stuff your arm up under the upper intake, along the valve cover, and feel for warm air escaping anywhere along that pipe. If you feel any, it means the pipe is broke, and your emissions arnt doing jack on that cyl.