Auxiliary pump 2010 and forward - Usage?

[Helmsman]

Originally Posted by Redd

Yes that is also one of the options I considered. But I'm a bit OCD and don't like to see a persistent code. I ordered a low mileage used one off ebay for cheap so let's see how that works out.

I've also been thinking about bypassing the coolant hoses when I replace the pump. Since we know heat causes these pumps to fail, if I bypass it and do a heatshield around the pump itself, maybe I can get the replacement unit to last forever. Any thoughts on that idea?

Water getting into the engine due to the axle sealing giving up seems to be the typical root cause for the pump failure (there's a few good vids on YT). Not sure if its the heat or simply time that does it?

[Redd]

Hmm lemme check for signs of water ingress around the aux pump area, but I'm pretty sure no water is getting in.

[spammysammich]

Originally Posted by Helmsman

Water getting into the engine due to the axle sealing giving up seems to be the typical root cause for the pump failure (there's a few good vids on YT). Not sure if its the heat or simply time that does it?

Can you please link some videos?

[Helmsman]

Originally Posted by spammysammich

Can you please link some videos?

The one I found after quick search: https://youtu.be/w3OjsRUW2Cw

Like to remember there are another couple of repair vids, give it a search mate.

Cheers

[tol4o]

The problem with the pump are the brushes, you can replace them with carbon brushes and forget about any future problems with motor.
http://www.aliexpress.com/item/10050...8daKjjrnJ&mp=1

[Redd]

Today I replaced my aux water pump with a used unit from ebay. Everything works, no more permanent A6D1.

My car is a 2010 so it doesn't have REST. The car has spent majority of its life in hot climate (except for the first 2-3 years in UK before it got exported to Malaysia) where the heater is NEVER used. So theoretically the aux water pump should never really activate right? Well, not quite.

I took apart the old faulty pump and true enough, the carbon brushes were all worn down and there was carbon powder everywhere. My mech says that the aux water pump is also used to control HVAC temperature. If the pump was bypassed, ac temps would be max cold all the time.

So I guess whether your car has the REST function or not, this is still a wear and tear item.

[Helmsman]

Originally Posted by Redd

Today I replaced my aux water pump with a used unit from ebay. Everything works, no more permanent A6D1.

My car is a 2010 so it doesn't have REST. The car has spent majority of its life in hot climate (except for the first 2-3 years in UK before it got exported to Malaysia) where the heater is NEVER used. So theoretically the aux water pump should never really activate right? Well, not quite.

I took apart the old faulty pump and true enough, the carbon brushes were all worn down and there was carbon powder everywhere. My mech says that the aux water pump is also used to control HVAC temperature. If the pump was bypassed, ac temps would be max cold all the time.

So I guess whether your car has the REST function or not, this is still a wear and tear item.

Good job Redd. So clearly the pump is working.

Funny, "my" dealer strongly stated that my car (based on VIN) didn't have the pump installed. Fortunately I was still able to find and replaced it, to get rid of that annoying A6D1 code...

Cheers

[Zero Signal]

You both seem to have dct? I wonder if 2010+ manuals have them or not.

[Helmsman]

Originally Posted by Zero Signal

You both seem to have dct? I wonder if 2010+ manuals have them or not.

Yes DCT here. Believe also the MT have them due to by Redd' mentioned reasons.

[drwankel]

Add me to the list. Every time I've cleared this code it's come back for the last 5-6 years.

Don't really notice anything wrong. DCT behaves perfectly. The only cooling issue this car has is getting hot in bad traffic on a hot summer day.

I never did anything about it. The car is a 2012 and doesn't have a rest function. Wasn't entirely sure what it did. However, based on those pictures Redd posted, it seems like I should do something. The way the pump fails is by being used, so clearly it was doing something.

Kind of funny to see a thread revived pretty close to when I was looking for it.

[Helmsman]

Originally Posted by drwankel

Add me to the list. Every time I've cleared this code it's come back for the last 5-6 years.

Don't really notice anything wrong. DCT behaves perfectly. The only cooling issue this car has is getting hot in bad traffic on a hot summer day.

I never did anything about it. The car is a 2012 and doesn't have a rest function. Wasn't entirely sure what it did. However, based on those pictures Redd posted, it seems like I should do something. The way the pump fails is by being used, so clearly it was doing something.

Kind of funny to see a thread revived pretty close to when I was looking for it.

Might as well replace it. As mentioned earlier in the thread it is very straight forward assuming you have a smooth way to cut the coolant, such a couple of cheap hose pliers. The pump isn't even bolted, simply slides in with rubber washer.

[Redd]

Found some interesting info related to the function of the Aux water pump from another thread. Putting it here for reference:

https://www.m3post.com/forums/showthread.php?t=2093028

Looks like the coolant exits the engine at the back of each cylinder bank into metal tubes that join and feed a single hose running to the DCT heat exchanger. Return line from DCT runs to auxiliary water pump, which then feeds supply to heater core through the bulkhead.
Return line from heater core runs straight to the return pipe to primary water pump.

Looks like temp sensors in the transmission control the aux pump, so even removing the full HVAC system wouldn’t stop the aux pump from running.

[Helmsman]

Originally Posted by Redd

Found some interesting info related to the function of the Aux water pump from another thread. Putting it here for reference:

https://www.m3post.com/forums/showthread.php?t=2093028

Looks like the coolant exits the engine at the back of each cylinder bank into metal tubes that join and feed a single hose running to the DCT heat exchanger. Return line from DCT runs to auxiliary water pump, which then feeds supply to heater core through the bulkhead.
Return line from heater core runs straight to the return pipe to primary water pump.

Looks like temp sensors in the transmission control the aux pump, so even removing the full HVAC system wouldn’t stop the aux pump from running.

Thanks Redd. I wasn't aware that the DCT sensor controlled the aux pump but makes sense if thats the case.