Advice on replacing 135 thermostat please.

Bit of a pain isn't it?
Water leaks with these cars is very scary for obvious reasons and they hold so little water to start with.
I did have some oat in the water so it was pink on the floor.
It's drained and waiting for the parts.
Good luck with yours.

What do you think of my thoughts earlier on not cold starting?
I don't have a P Scan..yet..but will eventually.

I would only comment on problems within my terms of experience.
You will have looked at all the parts which I would have checked & if after verifying those items & found little to be concerned about, it’s time for an OBD reader.
Those with a PScan would have already have had it on the car, hence my opening comment, however your car is a tf as far as I recall, you might be able to glean some information of a cheap reader.
I had an ELM ??? remote reader on my departed tf, this reported to my phone, I didn’t use it for serious fault finding, I didn’t have any faults but it did log some interest stuff.
It wasn’t expensive at all & it could be the window through which you might view your mystery.
It’ll be in one of the drawers & you could gladly have it, providing I could find it.
M

I do have a cheap OBD reader that works on the Yaris but it won't connect to theTF. Ironically I have never needed it on that car.
I will buy a P Scan when funds allow but right now I have to rely on old brain power and there's not much of that left.
My main concern is having it watertight and it soon will be.
Hopefully the temp sensor and Iavc cure the poor start.
Will soon know!

I had to change the Coolant temperature sender in the TF (and the 90, immediately after), but the symptoms were rougher than yours, I believe.

It could well be the stepper motor, is that what you mention? 

I am sure you’ll work it out soon 😊👍🏽

 

Thank you Pedro I appreciate that.
I think it is the stepper motor not responding to the input signals. It doesn't seem to open to let air through to a cold closed throttle and yet hunts when the engine is warm.
I have ordered the ECT sensor and the stepper motor. I was going to try the stepper motor first but seen as it is drained of water I might as well just fit the sensor. In fact that is what I will do then fill it and see if that works. If not I will replace the stepper motor.
When I remove the motor and turn the ignition on I expected to see the plunger move to "a starting position" but it doesn't move at all.
Maybe it is stuck in the middle!

Pretty common problem in Defenders (mine does not have one anymore), I am sure TFs are about the same 😊