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Discussion Starter · #1 ·
Hi all. Recently i had an issue with the thermostat housing, being that it was cracked and leaking so i decided it was time to replace this. Also a few times when driving the coolant temperature would reach 100 Celsius or more. But it averaged 96 degrees Celsius.

After replacing the thermostat housing, which came with a new thermostat and pump. (I reused the old temperature sensor)

The leak has been fixed but the cars temperature seems to low now. On an average drive for about an hour the car would run anywhere between 72 degrees and 82 degrees. When stationery the temperature would increase up to 90, but as soon as i start driving it decreases again.

Could this be a faulty thermostat even though it was brand new. Or could it be because i didnt replace the temperature sensor?

Below are a few photos which show the oil temperature respective of the coolant temperature. Wondering if i could get someones elses knowledge to help out. Thank you

(When cars been sat at idle for 15+ minutes)
180363



(When the car has been driven normally for after 40 minutes)
180364
 

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Discussion Starter · #3 ·
Sounds like the thermostat is stuck open. I've heard instances where non-OEM water pump kits have bad thermostats even though they're brand new.
What i suspected as well. I guess my next question would be could i just replace the thermostat with an oem one instead of having to replace the entire thermostat housing. Would it be advised to buy an oem one or buy an aftermarket thermostat?
Thank you
 

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Hiya mate. I would personally go OEM and change the whole lot. These cars are famous for thermostat problems so you need to fix it once and for all.
 

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Discussion Starter · #5 ·
Hiya mate. I would personally go OEM and change the whole lot. These cars are famous for thermostat problems so you need to fix it once and for all.
The thermostat housing is brand new so I see no need to replace that unless I need to in order to change the thermostat, which it appears I don't (not 100% sure). I'm having a hard time finding an OEM thermostat online, even when searching for the part number (06H121113B). Any chance you know who makes the original thermostat?
 

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I think there are several versions of the housing and there are different versions of the thermostat that fit the different housing. Audi/VW dealer might be your safest bet if you can't buy online and return easily.
 
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