So, I have been working through the issues my Scudo has over the last 6 months and I just cannot get my head around one problem.

2002 1.9d EL
Engine coolant temperature erratic.

Turn key, glow plug light illuminates, goes out, start.

Starts 1st time every time.

No faults in system, no EML.
Coolant temp gauge always goes to 90 normally.
Put any electrical load on and the gauge will gradually go to 110 and stay there.
If then left to idle with no electrical loads on it will even out at 90 again....

I plugged my scanner in today after stripping and repairing the engine wiring loom, recorded the live data and found that with the headlights on it will go from 90 to 110-120
then with the blower motor on full it will go to 215...

I have typed that correct, it read 215

I have replaced or done:

-cooling system flush
-removed matrix and thorough cleanse
-new radiator
-new thermostat
-pressure test and block test for head gasket leak (not 100% i know)
-new coolant temp sensor
-new rad fan switch
-engine wiring harness strip and repaired 8 individual wires due to chaffing
-new alternator
-new aux belt
-new timing belt
-new water pump
-new started motor
-all earth points cleaned and greased
-ecu removed and checked for water ingress
-double relay bought from breakers (poss a carry over fault)

I do need to send my instrument cluster away for an overhaul, speed is wrong, no mileage displayed, clock dead.
Is there a possibility that the temp displayed on any live data OBD scanner is mirrored from the dashboard or is it direct from the sensor/ECU?

Am I missing anything? I have checked fuses and relays

If anyone reads this and has any sensible advise I would be eternally grateful.

As you can see I have put a fair amount of effort into my van.

Thanks in advance, Dave

So today I drove 6 miles into Brighton, work traffic, fairly busy start stop.
The temp gauge was normal until i put my fog lights and heater on 1/2 way.
It went from 90 ish to max, then the needle dropped to roughly 100 but the stop light and temp warning stayed on.
Done my business about Brighton and drove home.
Only had the headlights on and the needle dropped off below 50 :-/
Now sitting with ignition on, engine off at 70, put the headlights on and it rises to 100 slowly.....
Watching the gauge closely it is fluctating between a couple of degrees, looks as though it is pulsing.
Can anyone make any sense of this!?!?