Before I remove the dash...

[ghost123uk]

Not sure what the other wire from the sender is all about, as it was disconnected (for the test) so all I can imagine is it provides the earth? So should I now test by shorting the 2 wires at the sender end to check the non-red/yellow cable...I think it was brown?

Plain brown is always an earth on these vans (and most other vehicles).

The sender itself is going to need a bit of rough handling to get it out - the wire clip is all rusted/snapped and looks well stuck in the grooves on the fitting. I'll tap it out as lightly as I can to try avoid damaging the housing.

Aye take care of that housing. See note below re the retaining clip.

Newbie question - will any fluid start pouring out when the sender is removed?

Yes, a bit will come out, iirc a pint or so, (as long as your thermostat is "closed"). When I did mine, I quickly stuck a bit of wet rag in there whilst I got the new one in my hand, ready for a "rag out and quick insertion" As long as your thermostat is working and the engine is cold (well you wouldn't do this job on a hot engine anyway ) then you shouldn't need to bleed it, although there is a plastic bleed screw on the top of the stat housing, a quick check there would not go amiss. Just fire up the motor and unscrew it a few turns. If there is any air in there it will come out, then coolant should start to come out = close it. Be a bit gentle with that plastic thumb screw though, they break a bit too easily.

So the sender is 2 wires and a square black plastic lumpy shape. Is that because only a black one will fit? I have no idea if the previous owner put the correct one in and I don't want to compound the error if that's the case...

Firstly, suggest don't buy this from JK. They have a bit of a rep for selling stuff that is wrong and/or iffy quality.

Here is a link to one from Brickwerks who work on these vans daily and only sell good quality Black one I cannot remember if they come with a new clip, so best order one of those as well (plus a spare one ) Clips = HERE

Same with the "O" ring, does a new switch come with one ? (Simon take note ! ) "O" ring = HERE Oh, just found a much cheaper "O" ring HERE

Brickwerks postage (well Royal Mail) is a bit dear, so if you need owt like a new "Dalek" cap etc, tag it onto your order

[Midge]

Plain brown is always an earth on these vans (and most other vehicles)

Good news. I'm pleased with my guess, and slightly relieved that the rather haphazard looking random wires hanging around everywhere are mostly brown

Yes, a bit will come out, iirc a pint or so, (as long as your thermostat is "closed")

I have no idea if there's a 'stat in there at all, let alone a closed one...

there is a plastic bleed screw on the top of the stat housing, a quick check there would not go amiss. Just fire up the motor and unscrew it a few turns. If there is any air in there it will come out, then coolant should start to come out = close it. Be a bit gentle with that plastic thumb screw though, they break a bit too easily.

Now it gets worse. The whole stat housing and surrounding gubbins appear to be whittled from billet rust. I expect trouble with the 4(?) bolts I have to tackle just to fit the new stat. Anything 'delicate' has probably already snapped off years ago - will take a close look though.

Does the thumb screw bleeding take place before I pull the sender or after the swap is finished?

Thanks for all the help and directing me towards the parts - much appreciated!

[ghost123uk]

Does the thumb screw bleeding take place before I pull the sender or after the swap is finished?

After silly

Those stat housings can be a nightmare if they have been neglected for a long time, but the good news is they are available from the above recommended Brickwerks.

[Midge]

After silly

Those stat housings can be a nightmare if they have been neglected for a long time, but the good news is they are available from the above recommended Brickwerks.

Sorry if it was a dumb question. I wasn't sure if you were advising I check the thumb screw thing to see if it gave indication of thermostat open/closed or not.

It's actually something I do after the swap, to bleed out any air that's sneaked in between sender-swaps.

Thanks for the pointer, and letting me know about the replacement part. Cheers

[Midge]

Well we've made some progress today, towards getting this show on the road...

Have swapped out the water temp sender and got my needle (and my mojo) back on track. Bit of a poor result on the thermostat (see https://club8090.co.uk/forum/viewtopic.php?f=37&t=130925" onclick="window.open(this.href);return false;) but the working gauge was priority #1 so it's a result.

Have also got a working oil light/buzzer having found a loose connection on the dash pod - well pleased

So... dash not yet removed, maybe still on the cards for the heater blower fuse problem.