Last month I bought a 2003 Discovery II, 4.6 V8, auto, 170,000 miles. I had to replace O2 sensors and a crankshaft position sensor and now it runs very nice... But its has what sounds like a rod or wrist pin clicking in the motor. The sound is louder under the car. You can't hear it when its cold but when it gets hot your can. Not real loud but its there. It also gets louder, almost a clicking noise, when coasting to a stop. I changed the oil, 10W40 synthetic but that did not improve the noise. The question is how hard is it to rebuild the bottom end on a discovery 2? Is it something I can do with normal tools? does the engine have to come out? Or what is the cost of a reasonable rebuilt block? I live between Atlanta and Athens Georgia.

 

Sorry but you need a new engine.
The 2003 model year came with a bad engine from the factory, they loose oil pressure and then grenade.
If you catch it early you can do a temp fix but it will happen again.
Looks like your truck is all highway miles so it lasted longer than most, 60-70k range is the normal life for a '03 engine.
There is a TON of info on the forum on this issue, do a search for "'03 oil pump" or the like.

 

Before we jump to a conclusion on the problem, are you certain it's a rod knock? There are many things that can sound very similar and your comment that it doesn't happen when it's could makes me think it could be an exhaust manifold leak. Does the frequency match the crankshaft rotation or roughly 1/2 crankshaft rotation?

Spike is right that a large number of '03s had oil pump problems due to improperly drilled locating dowels for the oil pump that would eventually cause it to crack and fail. However, these have been mostly narrowed down to an affected VIN range and there are lots of folks who have had no problems at all. Does your oil light come on when you turn the key and then go out when the engine starts? Is the oil light flickering at all at idle? If you have an oil pressure check done and it checks out OK, then I wouldn't suspect the oil pump as the root cause in this case and would start to look for other causes like a leaking manifold.

Yes, it is possible to replace a rod bearing in an '03 with the engine still in the truck.

Dave

 

I have an 03, outside the oil pump failure vin range, and I have had this same tapping noise for 30K miles. Can't tell where it is coming from exactly, somewhere in the bottom of the engine towards the back. Mine is only present once engine warms up and not all the time. Goes away as rpm's increase. If you do a search there are a quite a few people with this noise. I would think with 170K miles on the engine, just drive it.

 

With 170K and a slight knock when it is cold, you are probably looking at a re-build. May want to have your oil pressure tested, but you are probably looking at bearings. You will want to replace your oil pump gears and timing set. Check the cam for wear while you are in there, but you are probably looking at a lower end re-build. I would just run good synthetic on regular oil changes and keep an eye on it.

 

I need to add one thing to check.
Your catalytic converters, with the engine cold tap on them with a block of wood or a small hammer.
If they rattle have them replaced.
When they go bad they start to fall apart and the "guts" rattle and can telescope up the exhaust and sound like bad lifters or a rod knock.

 

do you hear the noise when the transmission is in drive?? or park?
I had a similar knocking noise on my 04 it only made the noise in drive it was brand new, I figured it was the transmission making the noise, it drove fine other than that.
Anyway about your question with the hi mileage it would be a good idea to pull off the the pan and front cover and inspect the parts, rod bearings in particular also you should be able to see the cam lobes for wear, and put on a new timing gear/chain set as well as the oil pump gears

 

I had a local mechanic listen to the motor. he was sure it was something in the top end. Since the oil light comes on only when it is susposed too - when it 1st cranks - and the noise is more click than clunk, he is thinking is a lifter or a valve rod. He said that the bottom ends are pretty strong and don't normally fail - He doesn't work for Land Rover so he would not be dealing with the oil pump problems. The exaust could be leaking too, how hard is that to check.

 

i bet you have the same problem as me... my engine ticks all teh time... no oil light... pump was toast and light didnt go off... i have 7 psi at warm idle and 15 psi at 2k rpm.... the noise you are hearing is probably lifter tick or in your rock shafts due to the lack of oil pressure reaching the top end. test your oil pressure BEFORE you do anything else from here on out!!!

if the oil pressure is low... dont even bother rebuilding the engine... i made that mistake and i'm still paying for it....5500$ later no engine... because my rebuild still wont make oil pressure