Coolant sensor

[TL17]

Seems I have the intermittent coolant gauge issue where shows nil, shows red with stop car warning, sits in middle, sits at 30% etc. From what I see it is probably due to a faulty sensor and this is where I’m a bit confused as see comments that the sensor is integral with the thermostat housing but I see no sensors on mine - late 2010 200hp - more inclined to think it’s tucked behind the turbo at the front?

So, 1 - symptoms sound right for dying sensor and 2 - location - behind TC about right?

if location right any short cuts to getting access as seems b tight in there?

cheers

 

[chrismac]

This is the Peugeot way, the 200hp instructions are quite different from my 156hp. I'm afraid it looks a bit more involved.

 

[TL17]

Thanks for this, I’ve since come across an excellent post re a recall for this model where the bleed screw on the thermostat housing was changed for a retrofit temp sensor that is then plumbed into the wiring where the old sensor was plugged - ie old sensor left in place just as a plug. Sound right?

 

[chrismac]

Not sure of the Peugeot Recall notice, try asking whoever posted it - maybe they can give you some answers.

 

[Benny2tatts]

So the new thermostat housing has the temperature sensor built in. You need to buy the wiring loom sensor to adapt this. I’ve just done this on mine last week.

 

[TL17]

Ok thanks - I’ve tried tracing the wiring back to a plug from the old sensor - but wiring taped together in mini loom and I don’t want to open that unless absolutely necessary. Where was the plug/socket you connected into - roughly? Did you open the loom?

 

[TL17]

Do you have any pics of job or adapter?

 

[Pedro]

The 200 GT & R is Hard wired into the Thermostat Tank housing that is why the tank needs changing I recall they brought out an upgrade for the 156 207cc etc which had wiring tails included from the sensor for plug & play into existing socket

 

[TL17]

Ok thanks, I will pop to Peugeot tomorrow and see what they have.

 

[TL17]

Ok further confused. Peugeot today gave me a sensor - a push in type with clip, not screw in - and said this is right for my chassis number. Of course the thermostat housing is original on this car and does not have any such hole to pop in the sensor - said to be just forward of the bleed screw. I still think my sensor is tucked under the t/charger. So can anyone summarise how to change this - new complete housing with sensor and adapter wire? Or sensor screwed into bleed screw hole of existing housing as I’ve seen described here - by far easiest to do - then re running wiring to it that originally went to old sensor. Confused! 1.6, 2010/11, thp 200.

 

[Pedro]

I was led to believe the upgrade was to replace the bleed screw with the sensor & just plug wired tails into existing socket so I assume that is why you been given that type of replacement on my 2013 200 GT there is no bleed screw in the thermostat tank & I know for a fact that the local dealers near me leave them to stand overnight after carrying out this job letting coolant level settle naturally

 

[TL17]

The sensor I screwed in is also a bleed unit which helps - the brass thread has a flat section for the purpose. The sensor is hard wired into the tails but there are two plugs - both male - one of which clearly plugs into the loom - the female socket unplugged from the built-in old sensor on the thermostat housing - which leaves a second male plug on the new sensor not used that I can see. It’s marked BMW despite in a PSA box so I did wonder if that’s for the BMW/Mini loom variant perhaps. Do you know if the thermostat is electrically driven or thermal? Reason to ask is that if electrical I’m wondering how it’s now powered as nil plugged into thermostat housing any more.

 

[Pedro]

The thermostat is as far as I know mechanical the coolant temp is monitored from the sensor & when its reaches a certain amount of degrees the ECU will command the Water pump to kick in thus starting the cooling cycle but as mine has wires coming from the inside of the tank at the back I can only assume you have a different set up ?

 

[TL17]

Mine has similar setup with the water pump friction-driven as necessary - the friction wheel unit/tensioner having an electrical connection. This is cutting in and out fine with the new setup.

Temperature gauge also now working so positive progress.

I will check the electrical drawings to see if more than the two wires to the thermostat housing - I seem to remember (but could be wrong memory!)
there were 4 wires coming into the original integrated sensor plug but only two are used for the new sensor so hence my question if the thermostat might be solenoid driven. However the “spare” tail left after connecting the sensor to the loom female plug is male as is the now empty slot on the thermostat housing where the loom connected before.

 

[TL17]

Ok from Sedre I can see it’s a four wire setup and seems to include a wired thermostat - not clear if can be seen in photo here. Will need to take another look at the car tomorrow.

 

[TL17]

Fixed - my fault (again)....
Spare tail DOES fit the old sensor hole on thermostat housing so 15 minutes this morning and done. Was worth checking as was pretty sure did not! So for those still with the old style housing this is a very simple 15 minute fix to a major headache. Thanks to the original guy who posted it back in 2015 - Peugeot has no information but were happy to sell me new housing, new sensor etc and hours to strip, drain, fit, refill and bleed etc. Phew