It is well known that diesel engines warm-up very lazily in winter. Especially modern, with a complex cooling system. Such as the 2.0 TDI CR CFGB diesel with robotic DSG6 transmission. This tandem is most often installed on the Octavia A5, Golf 6, Superb, and a lot of other VAG models. If the engine warms up badly and for a long time, it may not be the main thermostat that is to blame.
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The TDI 2.0 Golf 6, Octavia A5 engine does not warm up. Reasons
Symptoms of prolonged warm-up on VAG diesel engines are somewhat vague. The fact is that maintaining the operating temperature of modern diesel involved a lot of systems. It looks like the engine warms up well when driving on the highway and is able to hold about 90 °C for a long time.
However, it is worth crossing the city line and bumping into traffic lights, as the antifreeze temperature drops rapidly up to 55-60 °C, especially if it is very cold outside. There is a share of logic in this, but not in those cases when overboard +3 °C.
The first thing that comes to mind for a person with minimal knowledge in the design of a diesel engine – the engine thermostat has failed. And there is some logic in this, because the thermostat will run antifreeze in a large circle, not allowing the engine to warm up really.
However, the poor warm-up of the TDI CR CFGB Golf VI and Octavia A5 with the DSG6 robotic gearbox has its nuances. They also apply to diesels with a classic hydromechanical automatic transmission.
Here is the scheme of the cooling system of VAG cars in this configuration.
As you can see, the system has two thermostats – the main, the engine thermostat, and the secondary, which is responsible for supplying antifreeze to the radiator of the robotic DSG6.
The DSG6 thermostat is the cause of poor warm-up
Practice shows that this thermostat often fails and promotes the penetration of cold antifreeze on the radiator of the checkpoint. Naturally, in such conditions, the liquid will warm up for a very long time, if it can warm up at all.
The task of the DSG6 thermostat is to block the access of cold liquid to the radiator of the box until the antifreeze temperature rises to 87 °C. Only then does the thermal valve open and pass the antifreeze into the RKPP heat exchanger.
We draw a conclusion. If a diesel 2.0-liter TDI engine paired with a DSG6 box warms up for a very long time even at positive temperatures, the box thermostat must first be checked. In 90% of cases, it is he who becomes the culprit for poor engine warm-up.
How to check and replace the thermostat DSG6 VW, Skoda, Seat, Audi
First, find out which thermostat is needed for replacement. By design, this is the simplest thermal valve that extends the stem when the thermoelement is heated. The valve is placed in a plastic housing, which, if desired, can be disassembled by removing the retaining ring.
What is the best DSG6 thermostat to buy
However, in practice, these thermostats are not repaired, but changed. The original thermostat 1K0121113A from VAG costs crazy money, about $60. Fortunately, there are complete analogues that are several times cheaper, but work just as well:
- Mahle Original TH 575, the thermostat that is supplied to VAG conveyors, and it is they that are sold in branded VAG packages. Only with cut-down catalog numbers. It is best to buy such a thermostat.
- HELLA PAGID, TH575. Also a good option with a price of about $20.
- Каталожный № 73660, фирма Asam. Inexpensive analogue with a price of only 15 dollars.
- BORSEHUNG, B18777. The manufacturer claims that there is an original thermal valve inside the case. The price is 32 dollars.
- VERNET TH713575J, price 20 dollars.
- METALCAUCHO 30238, price 15 dollars.
- Stellox 2340296SX, price 24 dollars.
How to remove, check and change the thermostat DSG6 TDI CR CFGB Golf VI
There is no 100% effective method for checking the robotic transmission thermostat directly on the engine. Therefore, in any case, it will have to be removed. Fortunately, it will take quite a bit of time and effort.
To begin with, we will remove the air filter with housing assembly.
- Remove the chip from the mass airflow sensor. To remove it, you need to lift the tab and pull the connector towards you.
- Remove the far clamp from the intake manifold corrugation. We use a special puller or clamp.
- Disconnect the corrugation from the filter housing, remove the vacuum tube, and set this aside.
- Using a 5 mm hexagon (bit), unscrew the bolt securing the air filter housing.
- Using a T25 bat, we unscrew the two self-tapping screws of the air filter intake.
- Carefully remove the air intake cover. It is attached with three simple latches.
- Remove the air intake and corrugated tube from the bottom of the filter housing.
- We feed the housing towards ourselves, overcoming the resistance of the rubber damper, and take out the filter housing.
- In order not to drain the antifreeze from the engine, we block the fluid supply pipe to the DSG6 heat exchanger.
For this, we use either special plastic clips, as in the photo, or a regular welding clip, laying soft material between the jaws of the clip.
- We loosen the two thermostat clamps and slide them along the pipe from the housing.
- We bring the second branch pipe together with the thermostat into the access zone and calmly remove the thermostat.
- Check the thermostat by blowing. If you blow into the working thermostat, the air will pass with noticeable effort. A faulty thermostat simply blows through without air resistance. This indicates that the valve is stuck, and the thermostat needs to be replaced.
- Install the rubber protective damper from the old housing on the new thermostat.
- Install the new thermostat in the direction of the arrow on the housing. The arrow should point in the direction of the passenger compartment from the main radiator, along with the antifreeze flow.
Further assembly is carried out in the reverse order. In most cases, especially when we are convinced that the thermostat is not working, replacing the DSG6 thermostat will completely correct the situation with an engine warming up even in winter.
