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Danny, VW Mechanic
Category: VW
Satisfied Customers: 4004
Experience:  ASE Master Certified with L1 Certification, Volkswagen Certified, VW and Audi repair shop owner
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2004 VW Jetta Thermostat changing. How do I do it?

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2004 VW Jetta Thermostat changing. How do I do it? Where is it located

It depends on which engine you have, do you have the VR6, 2.0, or 1.8 turbo. Also if I may ask why you are changing it. It's my experience that many customers try to change the thermostat out for overheating problems and they almost never stick shut, it's something else 99% of the time. If I could know why you are doing it I may be able to save you the hassle of replacing a component that doesn't need to be replaced.

Customer: replied 7 years ago.

I have the 2.0.


I took it in today to a shop to get the oil changed and they said the service engine light was on so they checked it out. They told me it was the engine coolant thermostat that is why I am planning on changing it out.

If you could get me the p fault code number I can tell you for sure if it is the thermostat or not. There's like 10 cooling system codes, some of them mean it's the thermostat, some the temp sensor, some could indicate a faulty waterpump even. If it wasn't a VW dealership or a shop that does only VWs I wouldn't trust it but it's up to you.

Now to answer your question.

The thermostat is located on the engine block, it's right behind the alternator basically to the right of it. It's behind the plastic flange with a radiator hose coming off of it. You just remove the two 10mm bolts holding the flange on and it will come off, exposing the thermostat. Really simple to change.

If I have helped please remember to hit accept so the site will compensate me, if you need further assistance let me know.

Customer: replied 7 years ago.


The code was P2181.

That is correct then, that code is faulty thermostat 99% of the time. The only other thing I would advise is to check the color of the temp sensor in the coolant flange on the side of the head. If it's black or green with a yellow dot they are known as having an extremely high failure rate and I'd think about replacing it just to prevent any future problems. The green without a yellow dot one almost never fails so it's just preventative action.


If I have helped please remember to hit accept so the site will compensate me, if you get stuck or need more assistance let me know.



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