2003 Disco 2 w/60,000 miles. Just replaced the O2 sensor in front of the catalytic converter. The service engine soon light is back on, 100 miles later, and the engine idles rough again. 250 miles after this I hear a constant ticking when the engine is on and I know it has to be a lifter. What gives? What is the cost of replacing a lifter if you take it to a shop?

 

Ok, first you need to replace all the O2's at the same time.
Second, you need to stop driving the trk and write down your VIN# and post it on here. Not sure if you are aware of this but '03's have a reallyhigh failure rate of oil pumps. It is only a certain VIN range. That could be your ticking that you hear.
You can also call your dealer with your VIN# and ask them if you are in that range.
But if you post it on here we can tell you.

 

Vin is SALTY16443A798712

 

What are your fault codes?
Why do you think you need to replace a lifter? Could be an exhaust noise or rocker arm, both are more common.

 

Is his VIN# in the bad oil pump range Mike?

 

The VIN range is all 2003 Discoverys ending with 3A771801 – 3A808362 , so yes hes in it.

 

Go have your oil pressure tested. If the oil light comes on while the engine is running shut it off!!

 

OK, had it looked at by a repair shop. They said the engine is really dirty but the oil is clean. The bearings are bad and the crankshaft needs reground and a lifter is bad. $3500 worth of work. I had the 60000 mile service done 1000 miles ago at Land Rover of Tulsa and they would have told me if the engine was dirty when they changed the oil. I told the shop not to do the work and am taking it to Land Rover of Farmington Hills, MI. I talked to the Land Rover dealer service tech and he told me there is no way the repair shop could have checked all this for $85 which is what they charged me to diagnos this problem.

 

Yeah that shop is trying to take you for a ride. The only way to tell any of that about a engine is to tear it open. They didnt do that for $85. Second opinion needed from a good shop.