Hobby 600 FSE 2000 Coolant switch

[Tar Ten]

Hi everyone, just bought my first MH and it had a problem with the temp gauge..( Yes I knew about it when I bought it )

When I picked it up it read about 110 on the gauge and was pulsing a bit so put it down to dodgy sensor, bad earth.....
Whilst driving it home I noticed it creep upto the red line...stopped...no fans on...no signs of overheating in the engine bay..disconnected plug and reconnected
Left it 30mins... no change with ignition back on..straight upto red just short of 130 on the gauge...
Started driving again and after 5 mins needle passed 130...water warning light on.... stopped again but no signs of overheating... no fans...Left it an hour this time with bonnet open... Ignition on and max scale but no warning light .. At this point I felt happy to drive the next 250 miles knowing it to be a fault with sensor and not engine...

Have just tested the front sensor and reads up and down the scale as it should..
38k ohms at room temp
39k+ with cold tap water
23k with water out of kettle after about a minute

Cleaned it off , popped it back in and straight upto 130 and engine hasn't been running for 2 days....

I have read that you can disconnect behind cluster to clear fault...Have had a look and my big mits are a bit tight, doesn't seem to be that much forward play in it.... but have also read that there are 2 sensors... im sure I can see another just behind thermostat..

Has anybody had this problem...
Anybody know where I can get elec drawings
Any parts catalogues

Eng Code: 8140.43

Any advice greatly appreciated...

 

[The Coops]

Is it on the engine? in which case what is the base model? ( Fiat Ford Renault)

 

[Tar Ten]

Yes on the engine... Its the Fiat Ducato 2800tdi... Left hooker

 

[The Coops]

Firstly look at the belt tension on the engine , anything black and rubberised if appears ok, Step 2 Try back flushing the engine, take out the thermostat and running a high pressure hose the wrong way around the cooling system, Step 3 next take off all the earthing points you can see/find and clean, ( and lightly re grease) Check the thermostat is working by sitting in a pan of cold water and slowly heating up on a stove, if not does not open there's your problem, if it does open its an earth issue and time and patience will find, if that does not work look at the waterpump. it might be buggered , After that you are looking at head gasket failures. check the oil and filling cap for emulsion

 

[Tar Ten]

Thanks for reply... Getting it out to my lock up tomorrow for a better look.. Already had a good look at the oil and it was clean....new filter as well.. no milky gunk or sludge in filler, or frothiness... The belts that I could get my hands to and torch on looked ok with good tension and squealing or signs of slipping or over heating ( get a better look tomorrow) ...
Drove 550 miles up the road with her and no loss of coolant...Engine was smooth with no loss of power and nothing from exhaust ...
Noticed when I removed front sensor that the coolant coming out was clean coloured and hadn't been mixed.. had a nice fresh slippyness to it if that makes sense...reservoir showed no signs of scum...

Will work through the list and see what I find...

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[Emmit]

As you can see by our avatar we have a Hobby. (650EC) The front end is 2005.

We had a problem with the temp. gauge in that it was always in the middle of the range regardless of the circs.
Sart it up, middle, heatwave, middle, cold and frosty, middle. You get the picture.

However, on changing the battery, (I kid you not,) it started to behave impeccably, and has done so ever since.

Suggestion. Disconnect battery and leave it off for a period, You never know. I've stopped trying to guess the vagaries of electrics.

 

[Tar Ten]

Hi guys, just a quick update on the switch.. Symptoms have changed a little since the last post..

Where now it goes straight to offscale with just ignition on ...

Ive cleaned all the earth points I can find... Disconnected from cluster....disconnected battery for a while...

When connected back up and ignition on ( cold) straight to full scale max... Disconnect plug from sensor ...straight to zero
So I am just waiting for a new sensor to arrive £13 and sew how it goes...

 

[Tar Ten]

Quick update... changed the switch and all hunky dory.... yaaaaaay