2010 THP156 Coolant Leak (Themostat & Rear Coolant Exhaust Pipe)

[Ravenous]

So my RCZ had developed a coolant leak that was getting worse and worse. Initial inspection showed a leak at the bottom of the engine from the gearbox.

I managed to pull the themostat and could see that it had split. Decided to pull the water pump also and replace at the same time. I glad I did as I could see that the coolant exhaust pipe that runs along the back of the engine between the water pump and thermostat had also split in the water pump. Suffice it to say removing this pipe was a ball ache but managed to remove it. It is held on via the thin coolant pipe running from the coolant tank down the left hand side of the engine below the water pump. Disconnected that pipe via the self clamping clip, unbolted at the bottom of the engine and using an endoscope to visualise the connection at the back of the engine I managed to get my hand down the back of the engine and remove the metal retaining clip connecting the thin host to the exhaust pipe.

However, I have no idea how I am going to get this connected when the new exhaust pipe is installed. Has anyone attempted to tackle this?

The current thermostat, part no V753452180-08, has the two 2 pin connectors but the sensor is at the top running parallel to the bleed valve. I see that there is a variation of this where the sensor has been relocated and runs at 90 degrees to the bleed valve and I’m not sure the electrical connector would reach this.

I contacted Peugeot and they couldn’t tell me which thermostat they I needed but quoted part no 9810916980. I’ve spotted one on eBay but this looks like the altered version with the sensor running at 90 degrees to the bleed valve and I don’t think this will work. Does anyone know what part number I need?

Peugeot are quoting £180 for the thermostat but I have found a mini original part for £120 which is identical to my current one - does anyone know if this will be ok?

I’ve attached some pics

 

[Verminator]

Well as you know that the prince engine is in the mini so many parts will fit as same engine....

 

[neilgsxr69]

I’m sure with the revised thermostat housing you also need the extra cable that allows connection to the existing harness

 

[Ravenous]

I’m sure with the revised thermostat housing you also need the extra cable that allows connection to the existing harness

As I understand it there are a few variations of the thermostat:

(A) 4 pin with integrated temp sensor

(B) 2 x 2 pin with removable temp sensor

I currently have the wiring for the 2 x 2 pin connectors.

However having searche online I can see two slight variations of the 2 x 2 pin version B:

B1. Temp sensor running parallel to the bleed valve

B2. Temp sensor running at 90 degres to the bleed valve offset slight down next to the large pipe that goes to the radiator.

I currently have version B1 and I don’t believe the wiring harness will reach the connection for the temp sensor on version B2 (although I may be wrong?)

I can’t seem to find the correct thermostat part number for version B1.

Doing a bit more digging online it appears my current thermostat with part no V753452180 is a Citroen part!

 

[Ravenous]

Looks like I’ve found some info.

It appears the thermostat was redesigned due to various issues on other vehicles.

The updated version has the relocated temp sensor and benefits from:
- electronically controlled thermostat
- reinforced structure
- new configuration of sensors

There is also an additional harness to extend the connector so that it can reach.

However, the recommendation is for a software update to be performed.

 

[Pedro]

They are normally "plug n play" as replacing the tank with a new one should not affect the electrics never heard of a software update needed the revised connections are for the 156 engines only the 200 & R are different as both are connected at the rear of housing

 

[Ravenous]

They are normally "plug n play" as replacing the tank with a new one should not affect the electrics never heard of a software update needed the revised connections are for the 156 engines only the 200 & R are different as both are connected at the rear of housing

Thanks Pedro, I’ve managed to source an identical part to save any hassle. Should be plug and play

Now I just need to figure out how I am going to get the new coolant pipe connected at the back of the engine

 

[Ravenous]

We’ll, I managed it, and boy it was a hell of a job. I managed to wiggle the coolant exhaust pipe through the gap at the back of the engine by twisting it 365 degrees as I fed it in, from the battery side.

Connecting everything up was the difficult part and took a few attempts. Here are some pointers:

1. Remove the battery tray for better access I should have done this during the removal stage! Don’t forget the one bolt in the passenger side wheel arch.

2. do not push the exhaust pipe all the way and dock with the back of the water pump. Leave it sticking out a few inches (water pump was removed in my case so I could see the pipe).

3. use a little lube on the plastic fittings so that they slide on easily (I used a tiny amount of washing up liquid)

4. connect the thermostat housing to the exhaust pipe with your left hand holding the exhaust pipe and right hand holding the thermostat. Use either a twisting or tilting action going back and forth and it should connect. Attach the spring clip.

5. now push the exhaust pipe and dock with the hole at the back of the water pump. It needs to slot in fully. Then hold this in place by bolting in the thermostat housing.

6. when connecting the coolant hose from the lower left of the engine this slots up the back of the engine and connects to the coolant exhaust pipe. Make sure the spring clip is already pushed in. Then feed the pipe up through the back and hold in place by the bolt that attaches to the block. Then from the top left hand side of the engine feed your hand through and feel for where the two pipes meet and connect them together. You should hear the spring clip engage when connected.

Hope this helps

 

[Valex]

I taped a digital thermometer probe to the top hose of the radiator and checked the engine water sensor temperature with an OBD2 scanner app.
When I start the engine the two temperatures rise together (keeping so probably I have the thermostat valve stuck open.
Last winter the engine was taking ages to warm up and now the air conditioning is also not working.
Searching the right thermostat valve/housing and reading this thread I'm confuse .
My RCZ is a 156hp 2011, which one I should buy? Same as the one I have now or the revised one? Witch one exactly?
Probably I will buy a MAHLE one, reading some review around looks like it is the OEM one for the Mini Coopers. ... probably, no matter the brand, they are all made in China .