1999 Lincoln Navigator/5.4L/32 valve/314K+ miles
Loud tapping noise on passenger side. Quiet down for a bit when I used Lucas Oil Stabilizer, but tapping noise came back. Performance of vehicle seems normal, but really hard time pulling a 4K pound trailer uphill. I suspect it’s lifters because all the pulleys are good.
Would like to save the car for sentimental reasons. Please give me on what’s best to do.
Thanks for your service, Airborne!
Try to zero in where the noise is coming from. BRIEFLY run the engine without the fan belt to see if the noise goes away. If the noise is coming from the engine use a mechanic's stethoscope to try to find the source. For example, fuel injectors can get noisy and sound like a valve tap as demonstrated in a recent video by Scotty.
At that age and mileage if lifters are indeed worn I'd say realistically you're looking at installing a rebuilt engine, or taking a chance on a low-mileage used engine if one can be found. (Bear in mind there are lots of other expensive wear items to deal with down the road. If the engine is going can the transmission be far behind?)
https://www.youtube.com/watch?v=Lw4oPGL1b1c
