Why now

Why dos my p38 4.0 only get hot when i say hot i mean very hot just off red when off road.

I replaced the head gasket bout six months ago. But only got it though a mot last week. in the last week iv done bout 2000 miles alot i know. i can drive it on the road all day and night more or less non stop and not a bit of over heating will sit at 12 oclock.

Then show it some mud and abit off wheel spin and it gets hot.

is showing it some mud accompanied by slow forward speed,v/c fan working ,rad hot all over core ,

vc fan is working and rads is new.

jamesmartin said:

is showing it some mud accompanied by slow forward speed,,

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could i be that my foot is to heavy.

You sure the viscous fan/coupling is working correctly? Sounds like plenty of cool air is reaching the radiator in normal use but at the lower offroad speeds it's not getting enough, which all points to the fan not working...

Have you checked you have a thermostat fitted and it's working? Sound silly, but I actually found someone had removed my thermostat - really helpful!

vc fan was tested via puting a mates arm into it when engine was hot it dint stop but was funny.
the thormostat, water pump, and rad are all new.

fix it said:

vc fan was tested via puting a mates arm into it when engine was hot it dint stop but was funny.
the thormostat, water pump, and rad are all new.

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For all others looking to test the VC on the fan....

Don't do this....use a rolled up news paper instead....

Well the only difference between off roading and on road is speed and tork I think theres more preasure and load on the engine off roading, its then finding small faults that dont show when on road (Not a bad answer to say im multy tasking)