I have an octavia 2.0tdi 2008 with bmm engine and dsg.

The problem l have is the coolant temperature is very low. After some research l thought the inline thermostat was stuck open. But my car doesnt have any thermostat at all for the dsg.

AI Overview

On an Octavia 2.0 TDI (BMM engine) from 2008, the thermostat is located on the engine block under the thermostat housing. This housing is connected to a main coolant hose, and you'll need to drain the coolant and remove the hose and housing to access the thermostat.  

Yes the engine thermostat is in the block but on my car there is no separate thermostat for the dsg.

I wonder if its a good idea to add that thermostat

7 hours ago, Anders75 said:

After some research l thought the inline thermostat was stuck open

Makes sense

5 hours ago, Anders75 said:

but on my car there is no separate thermostat for the dsg.

How do you know that? Does the diesel not have one or has yours been removed? If so,by who?

When did you start to have problems?

5 hours ago, Anders75 said:

I wonder if its a good idea to add that thermostat

If it's been removed then maybe,but if not fitted from the factory then I wouldn't think its a good idea to ake the system more complicated.

What makes you think that it's the DSG thermostat and not the engine one?

Its not "missing", its not mount from the factory. I have change the engine thermostat but when its already drained of coolant l wonder if its a good idea to retrofit the inline thermostat for the dsg aswell

21 hours ago, Anders75 said:

its not mount from the factory.

Probably not necessary then.

21 hours ago, Anders75 said:

l wonder if its a good idea to retrofit the inline thermostat for the dsg

I wouldn't bother

On 05/10/2025 at 01:53, Anders75 said:

The problem l have is the coolant temperature is very low.

How low and under what conditions

Maybe the gauge sender is cactus

Or new thermostat not correctly working

Or air in cooling system giving false temp readings

When did the low temp issue begin?