They actually do make an aluminum coolant flange/thermostat housing. Bought mine from Aliexpress. No forums that I've found mentioned it, which makes me think this is a new product addressing an old problem (granted, these engines aren't that popular in the aftermarket/performance world) where the plastic warps overtime with multiple heating cycles, same as the oil filter housings (my S4s flange is made out of aluminum from factory). But you're definitely gonna need it! I've been through 3 already in the last year till I bought it. Even tried putting a layer of RTV down in the groove, then the gasket right before it fully cured to make it twice as thick (didn't do the trick long term either). Don't feel too bad you didn't know about it. JUST changed my PCV on my A4 and had no idea there was an aluminum pipe available. Mine broke EXACTLY where you stated (had to remove the thermostat w/o removing the crossover pipe to get the rest out; pretty difficult that way but easier than the process to take the whole pipe out). Didn't expect it as the one on my S4 didn't break (over 100K less miles, however). Bought a new plastic one on Amazon. Would've went to aluminum if I had known. Hope your new water pump is the improved design with aluminum blades instead of the oem version with plastic ones...😊
They actually do make an aluminum coolant flange/thermostat housing. Bought mine from Aliexpress. No forums that I've found mentioned it, which makes me think this is a new product addressing an old problem (granted, these engines aren't that popular in the aftermarket/performance world) where the plastic warps overtime with multiple heating cycles, same as the oil filter housings (my S4s flange is made out of aluminum from factory). But you're definitely gonna need it! I've been through 3 already in the last year till I bought it. Even tried putting a layer of RTV down in the groove, then the gasket right before it fully cured to make it twice as thick (didn't do the trick long term either). Don't feel too bad you didn't know about it. JUST changed my PCV on my A4 and had no idea there was an aluminum pipe available. Mine broke EXACTLY where you stated (had to remove the thermostat w/o removing the crossover pipe to get the rest out; pretty difficult that way but easier than the process to take the whole pipe out). Didn't expect it as the one on my S4 didn't break (over 100K less miles, however). Bought a new plastic one on Amazon. Would've went to aluminum if I had known. Hope your new water pump is the improved design with aluminum blades instead of the oem version with plastic ones...😊
Where you got the aluminum coolant pipe ?
What troubles have you hAd with your 2010?
"This job is not for the faint of heart"... Tell me about it! Nightmare! Did most of this on my A6 C6 2.8 FSI... Similar engine layout.
What was the labour hours on all this?