Any ideas

hi my 2004 td4 is playing games during normal use it is fine but when towing as soon as the temp gauge goes over half way it goes into limp mode stop for 5 mins and everything is fine until it goes over half way again.
is there a sender or sensor that will cause this it only goes past half way when under heavy load ie climbing big hills or holding at 65 - 70mph for a while. thanks in advance

Can't answer that problem for you but,
Water wetter, amazing stuff, pop it in your cooling system, thats it.
Used it in mine for approx 3 years after temp gauge kept going high whilst towing. Now it never goes over half way. Even towing from Rotherham to Angelsey up some serious hills.

Daft suggestion is your fuel pump above the rear wheel arch on its way out, when mine was dying the engine temp kept going high especialy up hill (thats how I came across water wetter)
Hope someone can answer your technical problem properly.
Mike