Thermostat Replacement - What Else

[frankinstyyn]

Hey guys, I’m fairly sure I have a thermostat issue. Been checking the forums here and I’m 99% sure.

Car is overheating when going around 60-80mph, fans running really loud, temp goes back to 90 when setting the blower to full, straight back up when the blower is off.

Car is 2012 B8.5, stage 2 engine and gearbox, upgraded pulleys and running around 475bhp. I’m in the UK and my old man is a mechanic so have good tools and in good hands.

This is a video I’ve seen which I’ll follow and replace the same parts - https://m.youtube.com/watch?v=zMGjs3pDoQQ

I’ll be replacing the thermostat so planning a few other things, this will be DIY on my drive… My list so far is….

Thermostat
PCV Valve
Supercharger Oil
Supercharger gaskets
Supercharger belt
Water pump

Is there anything else that you guys recommend and maybe any tips or advice….

Thank you in advance!

[a4lownslow]

You’ll want to replace this coolant pipe 06E121065N and either get new orings or replace the coolant crossover pipe as well


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[frankinstyyn]

You’ll want to replace this coolant pipe 06E121065N and either get new orings or replace the coolant crossover pipe as well


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Awesome! I’ll add that to my basket, thanks for the heads up, cheap part as well!

[Atrevido]

As you're going to replace the supercharger oil, don't forget to replace the SC bleeder screws as well. I went with the stainless steel ones from FCP Euro.

https://www.fcpeuro.com/products/aud...SABEgLMW_D_BwE

[SwankPeRFection]

Just FYI, if you’ve got an aftermarket heat exchanger with a bleeder on it, use that instead of the IC core ones and it’ll bleed just fine. Only reason the stock ones are used is because the stock heat exchanger is really low and there’s no bleeder anywhere else in that system. Also, just use a large enough/proper sided screw driver for those screws and don’t ham on them and the plastics work fine. Sometimes the stainless don’t play well with aluminum and can seize, but YMMV.

[frankinstyyn]

As you're going to replace the supercharger oil, don't forget to replace the SC bleeder screws as well. I went with the stainless steel ones from FCP Euro.

https://www.fcpeuro.com/products/aud...SABEgLMW_D_BwE

Awesome thank you. I can’t order from FCP Euro as it’ll cost my soooo much in import taxes - I’ll use the part number though! Thank you

[frankinstyyn]

Just FYI, if you’ve got an aftermarket heat exchanger with a bleeder on it, use that instead of the IC core ones and it’ll bleed just fine. Only reason the stock ones are used is because the stock heat exchanger is really low and there’s no bleeder anywhere else in that system. Also, just use a large enough/proper sided screw driver for those screws and don’t ham on them and the plastics work fine. Sometimes the stainless don’t play well with aluminum and can seize, but YMMV.

I have no idea if I have an aftermarket heat exchanger or not, is there an easy way to find out?

I’ll make sure to just take my time and be careful! Thanks for the tips

[6SpeedS4]

Maybe a carbon clean if the valves look bad.

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[frankinstyyn]

Maybe a carbon clean if the valves look bad.

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Is that worth a go even on a drive??

[sepheroth86]

Intake valve cleaning (carbon clean), PCV, thermostat, water pump, pcv hose with the solenoid on it.

[frankinstyyn]

Intake valve cleaning (carbon clean), PCV, thermostat, water pump, pcv hose with the solenoid on it.

Awesome - all those are ordered except the valve cleaning.. It is worth it and easy on a drive way??

[slykens]

Awesome - all those are ordered except the valve cleaning.. It is worth it and easy on a drive way??

I did it in my garage a few weeks ago during PCV replacement. If you have the money get the tank based blasting kit. I got the cheap kit that has a hose that goes to the media and it was suboptimal.

Biggest problem I had in not putting the car in service mode was rotating the engine. It was a total pain in the balls but I got enough out of it by using the supercharger belt on the crank pulley to get the job done.

I don’t know if the butt dyno knows there’s a difference but economy is as good now as the car was new - Facebook popped up a post from 10 years and 130k miles ago showing a highway trip at 27.3 mpg and I got the same the other night over 100 miles on the highway.

[frankinstyyn]

I did it in my garage a few weeks ago during PCV replacement. If you have the money get the tank based blasting kit. I got the cheap kit that has a hose that goes to the media and it was suboptimal.

Biggest problem I had in not putting the car in service mode was rotating the engine. It was a total pain in the balls but I got enough out of it by using the supercharger belt on the crank pulley to get the job done.

I don’t know if the butt dyno knows there’s a difference but economy is as good now as the car was new - Facebook popped up a post from 10 years and 130k miles ago showing a highway trip at 27.3 mpg and I got the same the other night over 100 miles on the highway.

Okay nice! Deffo worth a go, even if I just give them a good old clean!!

I’ll be putting it into a semi service mode so turning should be alright! Thanks for the advice!!

[slykens]

Okay nice! Deffo worth a go, even if I just give them a good old clean!!

I’ll be putting it into a semi service mode so turning should be alright! Thanks for the advice!!

Also, you don't *have* to use walnut shell media and a blaster. There's a few chemical options you can use but you *must* be sure the valves are closed to use those and you'll need a fluid extractor to get the fluid back out. I had my injectors out so I verified valves were closed by using the vacuum attachment over the intake port and feeling for any airflow into the injector port. You can also do this visually if you can easily turn the motor - FCP has a good video about how it works.

In my case I pre-treated with Liqui-Moly Valve Clean by letting it soak for about 15 minutes then working with a pick. I evacuated the fluids and gave it time to dry before using the blast media.