OK, I have a 2003 Discovery II SE with the BOSCH 4.6. It has 129,xxx miles. I bought it as a project vehicle, bought it with it overheating, and blown headgaskets. I replaced pretty much everything on this truck. New Main, Cam, and con rod bearings. Pushrods,lifters, basically everything. It started tapping the first time I fired it up after the rebuild, I have since put over 2,000 miles. Sorry for the long post. Here's my question: How dangerous is driving with a slipped liner? Only reason I ask is because the noise only starts when the engine is warm. It doesn't overheat, no loss of coolant or any other symptoms of a slipped liner. Any suggestions?

 

Evidence of slipped liner? Don't use any 0w, 5w or 10w oil unless temps below zero F.
......

 

When I rebuilt, no evidence of slipped liner. I'm just assuming since it only starts when warm. Yea, I use Mobil1 15w-50. I've no driveability issues, or codes. btw this was my first engine rebuild. I rebuilt while in Tech school

 

You have ruled out a lifter, the noise is lower?

 

Only reason I ruled it out is because the noise starts only when warm. wouldn't a lifter tap be there from cold? Top end is new, new cam,new lifters, push rods, rocker assembly. I listened with a stethoscope and noise seems to be coming from up top, near valve covers. I also think I might have an exhaust leak, because I am missing one nut where the cat bolts to exhaust manifold. But then again, wouldn't that be there from cold?

 

Not necessarily on the lifter. I had one that would tap only once warm. If it is a slipped liner, RoverMasterTech did a great write up on welding the sleeves in place. Might be something to look into.

 

Run it colder, do the inline thermostat mod and run a 160 or 170 degree stat - problem solved.

 

Are you using an aftermarket temperature gauge? Or do you reference the gauge within the dash cluster?

 

Yep. Run it colder will work.

Or PIN the liner with the Pin the liner procedure.

Or buy an LR3 and forget this bad engine.

 

I have aftermarket oil pressure and water temp gauges, but also monitor temps on my scan tool. On highway I run temp of 188.6, city I run temp of 194.0, and at idle I run 197.6-210.2 depending on how long I idle. Today with ambient temp being 91 degrees Fahrenheit, and the a/c on the coldest with blower on highest speed,temps only started to go above 197.6 after 15 min of idle and at 30 min of idle it didn't go past 210.2. only thing holding me back from the in line thermostat mod is deciding where to put my water temp sensor. right now I have it in the upper radiator hose.