Well, my 98 disco has been running excellent since the atf flush. I started noticing today that there is a ticking sound coming from the passenger side of the engine. I grabbed a screwdriver and listened to every part of the top side. Everything sounds good. I know that I have a minor exhaust leak on that side. Well it kept bugging me so I went underneath. I stuck a screwdriver up against the engine, right between the starter and the block, and there it is, the tapping sound. To further worry me, the truck doesnt start making the noise until it warms up. What am I looking at worst case? Rod bearing? Any other ways to diagnose? 1998 disco 1, 128000 miles 4.0 litre.

 

Sounds like a possible rod bearing to me. Only way I know for sure to see if that's the case is to pull the oil pan off. What weight oil are you using?

 

i think a rod bearing going out makes more of a clunking noise than a tapping since it is making a circular motion and not a reciprocating movement...not sure what would be tapping down there.

 

thats the thing, it doesnt sound like a bearing, it sounda like an exhaust leak, but i never had an exhaust leak get worse when warm. it does not have that deep clunk sound

 

oh, I use 10-40

 

i have 7mm cheap wires and plugs on this, i could not swing the magnecores yet. could these cause the tapping sound? could this sound travel through the engine?

 

Check your exhaust manifold gaskets to the down pipes.. See if maybe you can tighten them a little.. be careful those bolts get brittle

 

i tried that, the third bolt is wedged up against a heat shield. one was tight, and one was loose. the third i dont know. i went out to try to pinpoint the noise, if i listen from under the truck with a pipe to the passenger side bottom exhaust bolt nearest to the fire wall, i hear it loud there. it is a tapping, not a knocking sound, but it seems to be easier to hear with nothing than trying to pin point it. any ideas how to diagnose?

 

Your wires are not causing the noise.
As AK mentioned, I would also pull the pan, especially with your mileage and do a full inspection.

 

what kind of costs should i be looking at worst case? assuming rod bearings or a lower end rebuild?