2.4 brief overheating and loss of power - please help!!

2010 Defender 2.4 Puma

The vehicle behaves itself and pulls well in every gear when under normal driving conditions. The problem occurs when it’s towing a relatively heavy trailer and you encounter a long hill or a steep hill. It pulls well and the temperature gauge doesn’t move until I get to the next flat and I'm able to lift off but maintain road speed. As I lift off the power cuts (like limp home mode, but with no eng man light) and then the temperature gauge shoots right up (in that order). I’m left coasting, losing road speed and immediately the temperature gauge falls back down (over 5 – 10 seconds) and the power kicks back in and away I go again like nothing happened, the whole cycle takes less than 30 seconds.

I do believe it’s temperature related, as it happens when I’m asking it to work, but if the coolant temp was to actually be that hot, then surely there’s no way that it would cool back down instantly.

I’ve had the radiator out and flushed the coolant and changed the thermostat to rule out an air lock, blocked rad or faulty thermostat. I’m now thinking it’s more sensor related but I wondered if anyone has come across this before and could give me a strong indication of what to try next.

Massive thanks in advance!

Ross

If it’s a sensor diagnostics would show it up.
Perhaps you can lend one.

How’s your water pump? When you lift off it will spin slower as engine revs drop may take it over the heat threshold for limp mode after hard run but be okay normal conditions

RangeRoller dt said:

If it’s a sensor diagnostics would show it up.
Perhaps you can lend one.

How’s your water pump? When you lift off it will spin slower as engine revs drop may take it over the heat threshold for limp mode after hard run but be okay normal conditions

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I’ll check the water pump tomorrow as that seems pretty logical, thanks. Still bizarre that the temp comes back down so quickly. The gauge goes from sitting at 50% right up to 100 instantly, then comes back down in a matter of seconds. I’ll take a look at the water pump and if it’s ok I’ll get it into a a Landy specialist for diagnostic, unless anyone else here has had the exact same issue. Given that business is on hold with the pandemic, every penny is a prisoner! Thanks for your help.

Possibly the cylinder head temperature sensor -----

Hi, new to the forum and in search of answers to my own power loss issues! I have similar problems to this and wondered if you got to the bottom of it? Was it the CHT sensor? Thanks

Looks like the original poster posted his issue and not been seen since.