Water pump and thermostat replacement recommendations and best practises for a 2016 Polo

[R826583]

Hopefully! I’m about to pickup 10L of the Penrite coolant that is G12evo spec apparantly.

I went back to VW spares to ask about the bolts (they weren’t captive in the pump assembly) and they sold me 5x VWN91089601. Does anyone know the torque rating of these bolts for mounting the water pump?

Additionally, I’ve seen some water pump kits have a blue loctite-looking substance on the bolts. Do I need this or is using the bolts ‘raw’ fine? I’m trying to do everything to spec!

I’ll let you know roughly how much coolant it uses when I swap it tomorrow.

[ciclo]

Tightening sequence/stages:





Maybe there is something confusing in the 3rd stage. (poly V belt -> toothed belt, anti-clockwise -> clockwise).
I guess it's because the translations from German to English are not perfect, VW always warns that what is written in German in its repair manuals prevails.
With common sense, it is easy to interpret it.

You can use loctite on the screw threads. The repair manual does not indicate anything about this.
Please, if possible, take a picture of the leak before cleaning it (gearbox and surroundings) and another of the condition of the pump once you remove it, thanks.

[ciclo]

Repair manual (A) VS ciclo (B)





What do you think?

[R826583]

Thank you very much for the service steps! The translation is indeed a bit strange at some points. Like you said, common sense should be fine for most of the repair. I like B, your version, more so than A

Will do re the photos.

On another note the coolant is genuine GLYSANTIN® G65® according to the back of the bottle so it should be absolutely fine. (hopefully)

[ciclo]

https://cdn.website-editor.net/61024071 ... in_G65.pdf (1st pg)

[R826583]

Water pump was swapped today. All went well and the car is working fine. I have approximately (by eye) just over 2L of coolant left over… so it took just under in 8L (but don’t quote me on that I could have the measurement off). I would definitely recommend to someone to buy 2x 5L containers of coolant, it works well.

See the attached photos of the old water pump.

Thank you to everyone that has helped me with this. I appreciate it greatly

[ciclo]

Thanks for the images, it is the usual leak, fortunately detected in time.
Everything should be fine with the new pump and coolant.

[R826583]

No worries! Can you provide any insight as to what exactly might have failed in my pump? I couldn’t identify the failure looking at it briefly. Perhaps part of the plastic assembly cracked.

It’s not all happy news unfortunately… my Polo makes a whining noise in idle, which I’m pretty sure is drowned out by the engine noise when it has a load on it. It comes from the timing belt side of the engine block, opposite the water pump side. I thought it might have been the bearing in the water pump and hoped that putting in a new one would fix the issue. The whining noise is still there with the new pump in place I can’t look at it for a while though, perhaps a few days to a few weeks. I’ll create a seperate page for the issue on the form when I get round to looking at it.

Edit: Re the noise my suspicion is the tensioner on the timing belt but I’m not overly sure.

[RUM4MO]

That is a lot of coolant for a small modern engine, but seeing is believing, I had hoped or guessed that the 1.2TSI with 6MT would have about 5 > 6 litres - gauging how much my 2011 Audi S4 had.

I've forgotten, is your Polo DSG or 6MT just in case the cooling system for DSG has a coolant intercooler?

[R826583]

It’s a DSG

I’ve now got some reading to do on what a 6MT gearbox is… and some time to ponder about the mystery whine from the engine.

[RUM4MO]

As for your new/next issue - oh bother!!

Can't this not just be one of the auxiliary bits hanging of the front of the engine - maybe remove the auxiliary belt to see if that changes it?


Ah that could explain the volume of coolant better,

6MT = 6 Speed Manual Trans.

[R826583]

Please forgive my confusion but what do you mean by auxiliary belt? Which belt is that and what is it driving? I’m assuming it’s not the large timing belt (because the engine wouldn’t run with it removed) or the water pump belt (because it was just changed).

Good to know re the 6MT!

[ciclo]

There should be no coolant where the water pump pulley is located, so the leak originates from the seal between the pump pulley and the pump.


The whining noise may be coming from a bearing in the accessories that drives the poly-V belt/accesories belt/auxiliary belt (A/C, Alternator), - not the timing belt - .
The most common squeak noise usually comes from the poly-V belt due to wear and hardening. Current poly-V belts are manufactured with a 'carving' on the outside so that this does not happen.
You can do a little test/check by spraying a small amount of water on the poly-V belt while it is in operation, if the squeak noise disappears when spraying, replace the poly-V belt and tensioner. It is an easy and affordable task.

[R826583]

Ah of course, I see why the water pump would have failed now.

The actual belt makes the noise? Isn’t it toothed and thus not able to make a whining noise like a smooth belt would if it was slipping? Or like you said is it the tensioner bearing that usually gives issues? I’ll have to hunt down which component it is.

To be honest I didn’t realise that one could remove the auxiliary belt and run the engine, but I guess that makes sense because the A/C and alternator aren’t strictly needed. Does it mess with anything computer wise to run the car without the auxiliary belt?

[RUM4MO]

Also, remember that the front end auxiliaries, like the alternator and AC compressor do have shaft bearings.

The alternator will make more than usual noise if it is constantly loaded, like in the case where the battery is dying - or just even if its shaft front bearing is worn.

The AC compressor also has shaft bearings and many of these compressors are Sanden and were known by VW Group to have been passed out of the Sanden factory with free moving debris inside the compressors, hint, it seems that, well in UK, proper Indie VW Group workshops will NEVER supply and fit Sanden compressors, only Denso it seems.

I think that there a recommended mileage for replacing the auxiliary drive belt - really only to avoid it breaking up, and with a belt driven cam belt engine, the cam belt is only protected by thin plastic covers, which means if or when the front end auxiliary belt starts to fail, it can get caught up on bits at the front of the engine, including this cam belt cover - then you can really end up with a serious problem.