2001 LR Discovery Series 2 overheated yesterday. Found small plastic tube running from fill chamber across top of radiator (beneath plastic cover) had burst. Seems too easy to fix to be real problem. Am I just lucky or would there be something else going on?

 

Those plastic coolant pipes get brittle and break easily once they age. You should replace the pipe or covert it suitable sized coolant hose. Your "luck" will run out if not done soon if it didn't yesterday. There is another one that connects to the throttle body heater.
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If one of the lines is brittle, then all of the radiator hoses/lines are probably in similar condition. Even the plastic Tees on upper and lower hose assemblies will crack and cause major problems. If you are still running with the red antifreeze, that should be drained and flushed well, then refilled with distilled wAter and green ethylene type coolant. Replace all of your hoses with a kit from one of the retailers. Make sure that the fan clutch still has strong resistance and pulls air properly. Any signs of coolant leaks should be traced and repaired immediately. Install a genuine LR 180 gray thermostat. Do not use the factory dash gauge as the engine temp indicator. It is not accurate and will only indicate overheating after the coolant temp has reached 240 deg F, where then it will begin to move straight to the red. If you are not using an aftermarket gauge, you should be.

 

What aftermarket gage should we be using? ...and how is it installed?

 

Do a search on the Ultragauge. There is a thread at the top of the Disco2 forum by DiscoMike that has a list of maintenance items to be done that should keep your truck functioning reliably. The D2 has a tendency to become very unreliable without a steady upkeep, as high operating temps/high underhood temps leads to failure of spark plug leads, gaskets/seals, cooling system components. You want your coolant temps to be under 200f, which you could only know with the assistance of an Ultragauge or similar. You could also get a dedicated water sender and temp gauge that taps directly into a coolant hose, but most use something that taps into the ECU so that you can have all vital and secondary info displayed, such as O2 sensor function when diagnosing other problems in the future. Shell Rotella 15-40 is the rec motor oil, along with a high quality filter; personally, I use a quart of Lucas oil stabilizer with the Rotella. Most of your parts/sensor replacement should be OEM/genuine, not cheap aftermarket. Just research and read through the threads. All the info that you need to keep your Disco running reliably is here, and there is a lot that you need to know.

 

Firstly, I can recommend the Ultragauge. This is an excellent device that is (kind of) helping me diagnose a overheating problem, (segway to my overheating problem) here is a screen shot of the ultragauge at the end of a 7 mile drive.

It was doing this for a while before getting worse. Before I had the attached data, I thought it could be the thermostat so I changed that and you can see it functioning on the temperature trace.

Any help would be much appreciated.



Ian