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Discussion Starter · #1 ·
Hi all,
Bit of a long story, but recently I had my water pump replaced on my 2016 R-line v8 TDI due to leaking coolant.
Since receiving it back, I noticed that the car was not getting up to temperature, and would often not go above 70c. The temperature would also sometimes drop drastically if I turned on the A/C also

I checked for fault codes, and was receiving an intermitten fault
4875 - Coolant Pump 2
P261A 00 [096] - Open circuit
Intermittent - Not Confirmed - Tested Since Memory Clear

This part was replaced by my mechanic. Unfortunately, the low temperature kept occuring, and I took the car back for them to have another look.

They advised me that no error codes were being output, and they had no more ideas as to what was causing the issue. They did raise however that they noticed one of the smaller coolant lines clamped off when they replaced the main water pump, and hadn't put the clamp back on (as they didn't know what it was for and assumed it was 3rd party and shouldn't be there).
They've since re-installed the clamp, and the car now gets up to temperature as expected and all seems fine.

My question is, what would this clamp be for? They said it's made in Germany so I assume it is possible that it should be there, I just don't understand why this would be a factory item? Is there a possibility that it's Dieselgate related and part of a fix VW had to do?

I've attached pics of the clamp in question. I'd love to hear if this is fitted on other 7P V8TDI owner's cars as well, or if there is a larger issue with my car somewhere that is potentially being masked by the addition of this clamp?

Any help is much appreciated!
 

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Discussion Starter · #3 ·
To be honest I would loose sleep if that medieval torture device was fitted to my vehicle......

TonyB
Hence the reason for my post! I bought the vehicle 2nd hand around 35,000kms ago and have only serviced it at this mechanic.

Looking to confirm how other v8s look in this regard before I move forward with any other investigation. My mechanic is out of ideas so it may mean a costly trip to VW if no one can help me figure out what the hose is for which is being clamped off. To be fair though the car hasn't skipped a beat for the 18 months I've had it with the clamp in place. It's done a fair bit of 4x4 and a lot of towing with no evident cooling issues.

Cheers,
Clutrz
 

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Discussion Starter · #6 ·
Hi Both,
I appreciate your responses and confirming my fears.

What is the purpose of this auxiliary pump? What system does it support?
Given that I've now replaced the main and auxiliary pump, and the car runs too cold with the clamp removed. I'm after suggestions of what other parts may have failed that is allowing (I assume) water to bypass the thermostat and continue circulating through the radiator causing it to run too cold.

Any help is much appreciated. I'm likely way out of my depth here though and may just have to bite the bullet and take it to VW. It's frustrating that the car is not throwing any errors though so I'm not sure how quickly the cause will be identified and resolved.
Cheers,
Clutrz
 

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Discussion Starter · #9 ·
The SSP 467 on the V8 TDI and also the Erwin manual section on the engine provide lots of details to understand what's going on. From a quick look it appears the electric pump in question is dedicated to the EGR cooler. I am not sure if there is a second electric pump somewhere for the internal cabin heater and transmission heating / cooling or whether these circuits come off the main pump or the EGR pump. The are lots of valves and a couple of thermostats at least that control how these circuits work. It would take me about 4 hours to figure it out with the manuals in hand and going over the actual piping circuits on the engine, i hope I never need to do it :).

I suspect most mechanics ( VW dealer or independent) would take even longer to figure it out to diagnose your problem better, if they could be bothered which is probably why the clamp bodge fix.

cheers
Rohan
Thanks very much for this. The SSP 467 document was very helpful. I can't seem to find an engine repair manual for the v8 tdi on the erwin site though. I'll happily pay for a subscription if manuals are available for my car model/year
 
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