jwick

Hi,I need to replace the thermostat on my 4.2 L A6. I have found on my repair cd that the thermostat housing is located next to the water pump just above the oil pan on the side of the block. Has anyone done this job or know if it is a straight forward job? how is the access to this housing? I would hope the engine would not have to be raised up. Any suggestions or help is appreciated. Thanks john.

2005 Audi A6 4.2

Crizz

Did you ever figure this out? I have an '06 A6 4.2 that needs a stat. Noticed you're in MN too - I'm in South Mpls. Any wisdom?

jwick

Hey, I did indeed install a new thermostat in my 4.2 A6. I could only Buy the thermostat mounted in the alluminum housing which hase 4 bolts holding it on the water pump housing.I could not buy just the thermostat. Very simple straight forward job. No special tools or problems. replacing took care of my very slow warm up problem I was having.

John Wickenhauser.

jujuC6

Any DIY? I think I am experiencing the very begining symptoms of slow warm up. Really considering doing the carbon clean up so might as well do this job while I am at it too.

Tthorsby01

Hey there. Newbie here. I know this is a 6+ year old thread, but I've recently ran into the same issue. I have a 2005 A6 4.2 with about 92k miles and the thermostat just went out on me entirely today. Had been slow on warming up, now it's not warming up at all, especially with it being so cold here in Michigan.
My questions are;
1. You stated easy job, no special tools or problems. There's nothing I need to remove besides the under body cover to get to it?
2. Did you have to drain all the coolant out? What coolant, if you remember, did you use to refill it?
3. Where did you purchase the thermostat housing/assembly from? (Found mine on Parts Geek, with a gasket)

Any and all input would be greatly appreciated. I'm confident I can tackle this job myself, just would like as much information I can possibly attain before diving into this job. Thanks in advance.

raj99

Hi,

Let me help out on this ask, since I recently did this when the radiator was replaced.

1 - it is NOT an "easy job". For my model year (2006), it required the removal of the entire front of the car to make it accessible and for you to remove the assembly which contains the water pump and the thermostat. Take a look here: Fixing my coolant leak

2 - The coolant will be all drained and you can use G13 or G12++ with no issues. I used the Pentosin Pentofrost E; Violet

3 - I bought my parts direct from Audi and I can tell you that you'd be making a mistake just changing the thermostat with all that work, I'd definitely replace the waterpump as well and also the serpentine belt, idler and pulley...at the very least.

Tthorsby01

You definitely weren't kidding when you said the entire front end... that looks like one hell of a job. Your input is definitely appreciated. But, I just humored myself and hooked it up to an OBD II reader and double checked everything... come to find out, the coolant temperature was exactly where it needed to be, but the gauge never moved. So that tells me something else went wrong... definitely a weight off my shoulders. At least it's just the gauge that's not reading, and the sensor is working. Still something that needs to be addressed, but not something that's potentially causing more damage from running too cold.

Again, thanks for all your input. It will definitely come in handy in the future when it comes time to fully tackle a job like that.