Audi B8 2.0 tdi CAGA coolant temp problems
- Thread starter Don Mundo
- Start date
Sorry, late return to this thread. Yes, the pinhole is in the pipe already, so you pull the pipe as if you're pulling it off, but stop short when (hopefully) air followed by a fountain of coolant emerges from the pipe.
Thank you for the picture. I found the pipes going into heater core after removing scuttle panel. However A6 C7's pipes are positioned in a way that makes it very difficult to pull the pipe with one hand while holding hose clip clamp pliers with another hand. I will try again this weekend with someone assisting.Sorry, late return to this thread. Yes, the pinhole is in the pipe already, so you pull the pipe as if you're pulling it off, but stop short when (hopefully) air followed by a fountain of coolant emerges from the pipe.
Hi
I have the same problem as you have on my Audi A4 B8.5 2013 CGLC.
I have changed:
1- 03L121111AD termostat
2- 1K0121113A one way termostat
3- 3W0122351 Non-return valve
I have found that there are two Non-return valve "check selected area 25 ". You can try touching this valve and you will see the difference after and before.
I haven't changed the other one yet. but I thought I'd share this with you.
I have the same problem as you have on my Audi A4 B8.5 2013 CGLC.
I have changed:
1- 03L121111AD termostat
2- 1K0121113A one way termostat
3- 3W0122351 Non-return valve
I have found that there are two Non-return valve "check selected area 25 ". You can try touching this valve and you will see the difference after and before.
I haven't changed the other one yet. but I thought I'd share this with you.
https://www.oemvwshop.com/3w0122351-non-return-valve-p745871/
Attachments
Hi guys,
I have a 2011 A6 (C6) 2.0tdi, Manual transmission.
I've experienced similar issues and today had the thermostat housing replaced however the cabin is still not getting hot using the climate control but it does work when you set the fan speed to manual. Will replacing the part 03L 122 157 M (number 25) will solve this issue? Also my heated seats are only get slightly hot.
Thanks
I have a 2011 A6 (C6) 2.0tdi, Manual transmission.
I've experienced similar issues and today had the thermostat housing replaced however the cabin is still not getting hot using the climate control but it does work when you set the fan speed to manual. Will replacing the part 03L 122 157 M (number 25) will solve this issue? Also my heated seats are only get slightly hot.
Thanks
Szia Tamás! Remélem eljut hozzád az üzenet! Nekem is hőfok bajom van! Megvettem a két termosztátot remélem fog javulni a helyzet. (2008 AUDI A4 B8 2.0 CRTDI) Írj ah olvasod ha menet közben elakadnék valakihez tudjak fordulni! Üdv! István
I changed the coolant temperature sender (VW part number 06A919501A), put in a new O-ring, and changed the coolant. Unfortunately my problem still persisted. To date, I have changed the main thermostat, coolant temp sender, and coolant. Did not make a difference.
I have an interesting discovery that I think is worth sharing.
Two weeks ago I cleaned the coolant temperature sender's connector using WD40's electrical contact cleaner, and now the temp gauge on the instrument cluster shows 4 dashes (4th one being 80~90 degrees Celsius). I have logged the coolant temp using VCDS a few times, and I am getting on average 10 degrees more at the end of my commute. Although it is not hitting 90 degrees by the end of my commute and temperature would decrease when car is not under heavy load/driving downhill, it is nice to see cleaning the connector sort of made an improvement.
Two weeks ago I cleaned the coolant temperature sender's connector using WD40's electrical contact cleaner, and now the temp gauge on the instrument cluster shows 4 dashes (4th one being 80~90 degrees Celsius). I have logged the coolant temp using VCDS a few times, and I am getting on average 10 degrees more at the end of my commute. Although it is not hitting 90 degrees by the end of my commute and temperature would decrease when car is not under heavy load/driving downhill, it is nice to see cleaning the connector sort of made an improvement.
Szia,
most találtam rá erre a fórumra és ugyanezzel a problémával küszködök, ha esetleg aktív vagy még a fórumon el tudnád mondani részletesen, hogy pontosan mi oldotta meg a problémát?
Köszi!
Hey man , please let me know if you fixed the issue. I have the same car as you and after changing thermostats its better but still very hard to reach 90 celcius and also drops. The only thing i havent changed is non return valvle. Please let me know how you fixed it!
I have had the same issue with my A6 (2009 4F2, engine CAHA) for more than 5 years ever since I bought the car and last winter the issue seems to have gotten worse. We have here nice frosty winters sometimes dropping to less than -25 celcius, in those temperatures the temp gauge doesn't even move unless I drive on motorway at high speed for more than 10 minutes. But even at a moderate 0 celcius the car is very slow to warm up and will not reach 90 on gauge unless on motorway.
I was considering replacing the main thermostat years ago but didn't do it because I just thought this is a diesel feature and forgot about it. Now I saw the fuel consumption is again high during winter and I became interested in this problem again. I found this topic which made me to do some more research and I think I have found an explanation.
The German engineers have decided to install an auxiliary water pump (called V178 in VW diagrams) whose job is to circulate coolant through the EGR cooler when the main thermostat is still closed. I found that this flow actually goes in reverse direction through the main radiator and goes back inside main coolant pipe into the EGR cooler. Then there is main coolant flow circulated by the engine pump which goes in many directions (straight to main thermostat, heater core and oil cooler). The flow through oil cooler goes back into the EGR cooler hoses, but it is blocked by the EGR thermostat. Now if the EGR thermostat 1K0121113A leaks too much, it apparently will let the warm coolant mix with the stone cold EGR coolant coming from the radiator. I am not 100% sure about it, but I think there has to be a small leak through the EGR thermostat, otherwise it would never reach the opening temperature. But it is probably the issue that the EGR thermostat starts to leak too much or gets stuck open.
Then I figured that there must be an easy way to test this: disconnect the V178 pump (part number 19). I did this and bingo: it looks like engine temperature is now rising much faster and it seems to be more stable. I have only briefly tested it but I am pretty sure there is a difference. Of course it throws a fault code from disconnecting the pump but that is a small problem. So in my case the problem likely is the EGR thermostat.
Now many guys have stated that changing the EGR thermostat has not solved the problem for them. I also found this which is quite interesting:
https://www.clubtouareg.com/threads/dyi-egr-cooler-bypass-valve-actuator-repair.288901/
basically if the EGR cooler bypass valve is malfunctioning, it will start cooling the EGR gases right from startup which will rob the engine of its heat and cause the same symptoms. This is also easy to test: just see if the EGR bypass valve is moving when the engine is started. In my case it was working.
I was considering replacing the main thermostat years ago but didn't do it because I just thought this is a diesel feature and forgot about it. Now I saw the fuel consumption is again high during winter and I became interested in this problem again. I found this topic which made me to do some more research and I think I have found an explanation.
The German engineers have decided to install an auxiliary water pump (called V178 in VW diagrams) whose job is to circulate coolant through the EGR cooler when the main thermostat is still closed. I found that this flow actually goes in reverse direction through the main radiator and goes back inside main coolant pipe into the EGR cooler. Then there is main coolant flow circulated by the engine pump which goes in many directions (straight to main thermostat, heater core and oil cooler). The flow through oil cooler goes back into the EGR cooler hoses, but it is blocked by the EGR thermostat. Now if the EGR thermostat 1K0121113A leaks too much, it apparently will let the warm coolant mix with the stone cold EGR coolant coming from the radiator. I am not 100% sure about it, but I think there has to be a small leak through the EGR thermostat, otherwise it would never reach the opening temperature. But it is probably the issue that the EGR thermostat starts to leak too much or gets stuck open.
Then I figured that there must be an easy way to test this: disconnect the V178 pump (part number 19). I did this and bingo: it looks like engine temperature is now rising much faster and it seems to be more stable. I have only briefly tested it but I am pretty sure there is a difference. Of course it throws a fault code from disconnecting the pump but that is a small problem. So in my case the problem likely is the EGR thermostat.
Now many guys have stated that changing the EGR thermostat has not solved the problem for them. I also found this which is quite interesting:
https://www.clubtouareg.com/threads/dyi-egr-cooler-bypass-valve-actuator-repair.288901/
basically if the EGR cooler bypass valve is malfunctioning, it will start cooling the EGR gases right from startup which will rob the engine of its heat and cause the same symptoms. This is also easy to test: just see if the EGR bypass valve is moving when the engine is started. In my case it was working.