Land Rover Repair: Overheating of 1998 Land Rover Discovery V8i when towing, cylinder head gaskets, land rover discovery

Question
Hi

You have probably answered this question numerous times, but I really need to try and find an answer to this problem.
I own a 1998 Disco V8i manual. The vehicle starting running hot while I was towing a caravan and would go into the red. As soon as the engine was not working hard anymore, the temperature would come down and settle on normal. It never boiled over as I would stop as soon as the vehicle got too hot. There is no evidence of water leaking anywhere.
I have replaced the thermostat and had the radiator flushed as well, this seemed to help for a small while, but the problem is now back.
What course of action could you suggest?
Thank you.

Answer
Check you radiator for cold spots (flushing rarely has any effect).  Have the radiator rodded out or re-cored as needed.  Perform a block test to check for bad cylinder head gaskets and/or block problems.  You can also check the viscous fan coupling.  A bad torque converter will also cause the vehicle to overheat when towing.