Land Rover Repair: 96 Discovery overheating, combustion gas, internal failures

Question
Hi John - I have a 96 discovery that appears to be having some strange overheating problems. I use it as a family ski wagon mainly for club field access roads, pretty big climbs. First time it overheated, the gauge stayed just below half for the first ten minutes of the climb then slowly began to rise. I shut the engine off, allowed it to cool, then back down the mountain. Had the radiator removed and flushed. Replaced the front two electric fans and the viscous hub. Under normal driving conditions I have no problem at all, but still when I drive up the mountains, after about 10 minutes of solid up hill (low box steepness)it will begin to overheat. My question is, am I expecting too much from my disco? It is not using any water, or oil and it seems that it will handle it for a time then it becomes too much. I have read your blog on internal failures, but not sure if this is the case here. I did notice that if I left it is high ratio, it would begin to overheat quicker? Could this be a water pump issue?

Answer
It's certainly possible you have an unusual water pump problem, but overheating under load does often signal combustion leakage inside the block.  If I were you I would get a combustion gas leak kit (a liquid chemical that changes color when exposed to combustion gas) and use it to check the vapor from the coolant expansion tank next time you do one of those climbs.  That will probably tell the tale.


Good luck with it
Check out my car blog at robisonservice.blogspot.com and find me on facebook/robisonservice

John Robison