Heat expansion of copper could be worse that the Aluminium....not sure.

But i reckon the heat should burn up any rust/oxide stuff in the gaps.

I've been meaning to buy a blow torch, I'll give it a couple more attempts with the rust eater and the vice grips, then a 'heat' solution, then belt the absolute #### out of it, then drill it to death.

That should just about cover it I think - I'll stick the solution that worked on my webpage when it is done.

yeah mate a copper drift is a piece of solid copper rod that is used to direct force to one area the size of the diameter of the drift, like you could possibly knock it into the temp sensor reccess.... I think, but possibly the sensor will not go through that way, I can't remember on mine but I think the heat gun idea could get the metal to expand a tad and that could all be enough to loosen it enough to come out, plus when the metal area expands, the penetrating lubricant may find it's way to the concerning area and free it up

Err...what's a copper drift?

I'm not familiar with that type of tool.

I assume it's some sort of tube?

Mine did that too...
what i did was carefully use locking pliers ( vice grips or whatever ) and spray lube on the sender and wiggle and twist carefully, and mine came out intact and I used it again.

what if you heat the sensor area up with a heat gun and use a copper drift to gently tap it through inside the coolant passage then it should come out the thermostat housing opening?

Sounds like the sad truth had been layed upon me brother!

I'll give it some loving with some vice grips, drill and whatever else tickles my fancy with no regard for the sender itself....

When you gotta go you gotta go.

(I'll hold off until tomorrow Oz time) in case anyone else thinks of a brilliant strategy.

Thanks again all

Sadly, once it's stuck good & proper, then all too often you have to make a simple choice
Destroy the head to save the sender,.... or
Destroy the sender in trying to remove it, but save the head.

New replacement senders are not all that expensive & if you fit the new one with a little bit of a suitable anti sieze compound, & run only coolant, [not water] it should never stick again.

I had the same problem .pull the pin out on the sender end with a pair of pliers ,Then drill it out .A new sender will cost about 17 $ from repco .

ive had the problem before but straining my brain to remember how we got it out, definately destroyed it to get it out but still cant remember how, you can get at it from thermostat area but cant remember if that was the solution

Trip to the wreckers or repco for a replacement...
Then go about smashing it angrily, until it falls out.

I've not seen this problem before. Can you get at it from inside where the thermostat goes? Maybe a little leverage there will make it let go.

None of my repair books talk about it's replacement/removal.

Hopefully someone can suggest a method better than my destructive removal technique.

Chris