Thermostat and temp sensor location

[scardy]

Hi all,

Been having loads of problems with FR TDI the past few months, first oil cooler then crank sensor, so changed clutch and timing belt and pump at the same time. Expensive month!

Now the car is not getting up to temp and when it does start to rise, it starts to fall again when the engine is under no strain (coasting).

Am I right in thinking my next port of call is the thermostat and temp sensor? If so does anyone have a guide on where they are located? I will plug into diagnostics tomorrow to see if anything is logged.

Cheers

 

[Hamburgalarr]

I have been told that this is a characteristic of these engines they like to be worked hard. If i rag it about a bit it stays at temp happy enough.

 

[scardy]

No, it was thermostat, was absolutely knackered. I will post pics and a rough guide how to change for others who are interested.

 

[scardy]

Thermostat removal/repacement on Leon FR TDI PD 170 engine code BMN 2007 model

Tools needed:

• Torx 25
• Pozi/Philips
• 8mm socket
• 10mm socket
• 13mm socket
• 13mm spanner
• 16mm spanner
• Pry bar
• Hammer
• Gloves (if you want to keep clean)
• long nose pliers
• Hose clip pliers
• Ramp (preferably)
• Bucket (to catch water)

Firstly disconnect the battery, unless you want a shock from the aternator cable!

Remove the under tray so the water can escape when you get the thermostat out

Remove plastic engine cover (just pulls off)

The thermostat is located behind the alternator

Take retaining clip off bottom of EGR to release hose, you may not need to do thid but I found it helped when taking the hose clips off

Use the 16mm spanner to pull the auxillary belt tensioner (big bit of metal behind alternator) and slip the belt off the alternator.

Now remove the two 13mm bolts that hold the alternator in place, they are on the left hand side. the bottom one can be fiddly.

Use the pry bar to help wiggle the alternator free, watch you do not catch your fingers!

Double check you have disconnected the battery as this next bit could hurt, pull the electrical connector off and remove the two nuts that hold the power cable on the right hand side of the alternator. small one is 8mm and the other is a 10mm

Disconnect hose to the left of the EGR valve

Now you should have access to the two 10mm bolts that hold the thermostat in place, remove these then disconnect the hose

Remove thermostat from housing! As you can see mine was blown.

Now just reverse these steps to put it back together, you may also want to change the temp sensor whilst you have the thermostat out to save doing it all again at a later date. Also when you have reconnected the battery there will be some warning lights on the dashboard, power steering, traction control and tyre pressures. These will go out after you have driven around for a bit.

 

[hollandgirl4]

Hi, sorry to revive an old thread. But today I found out my coolant loss was due to leaking thermostat housing. The guide you have made is very helpful, is it hard to remove the housing once you've removed the thermostat etc?

 

[scardy]

Hi, thanks, hope the guide helps you out. The thermostat can only be removed after you have taken the housing out. Only 2 bolts holding it in plus the pipe clamp. The housing is easy to remove it's just the access required hence having to take the alternator out which is the worst part because of the auxiliary belt. Definitely easier with 2 of you for replacement of the belt. Patience is the key. Good luck.

 

[Asce]

I found it easy to remove the EGR and the cables from the back of the alternator. Does require knuckle joints for the socket though.

 

[ThirdLeon]

Thanks this was very useful, i used this to access the temp sensor in the thermostat housing.

Alternator was very tight to remove and also abit tricky to get back in place.

Im curious which would be easier/quicker, removing altenator or egr?

 

[Steeley G]

Thermostat removal/repacement on Leon FR TDI PD 170 engine code BMN 2007 model

Tools needed:

• Torx 25
• Pozi/Philips
• 8mm socket
• 10mm socket
• 13mm socket
• 13mm spanner
• 16mm spanner
• Pry bar
• Hammer
• Gloves (if you want to keep clean)
• long nose pliers
• Hose clip pliers
• Ramp (preferably)
• Bucket (to catch water)

Firstly disconnect the battery, unless you want a shock from the aternator cable!

Remove the under tray so the water can escape when you get the thermostat out

Remove plastic engine cover (just pulls off)

The thermostat is located behind the alternator

Take retaining clip off bottom of EGR to release hose, you may not need to do thid but I found it helped when taking the hose clips off

Use the 16mm spanner to pull the auxillary belt tensioner (big bit of metal behind alternator) and slip the belt off the alternator.

Now remove the two 13mm bolts that hold the alternator in place, they are on the left hand side. the bottom one can be fiddly.

Use the pry bar to help wiggle the alternator free, watch you do not catch your fingers!

Double check you have disconnected the battery as this next bit could hurt, pull the electrical connector off and remove the two nuts that hold the power cable on the right hand side of the alternator. small one is 8mm and the other is a 10mm

Disconnect hose to the left of the EGR valve

Now you should have access to the two 10mm bolts that hold the thermostat in place, remove these then disconnect the hose

Remove thermostat from housing! As you can see mine was blown.

Now just reverse these steps to put it back together, you may also want to change the temp sensor whilst you have the thermostat out to save doing it all again at a later date. Also when you have reconnected the battery there will be some warning lights on the dashboard, power steering, traction control and tyre pressures. These will go out after you have driven around for a bit.

Hi i have this problem now and wanting to fix it but i'm not able to see the pictures you've uploaded?