B8.5 s4 water pump

[S4lty1]

Noticed I've been losing a lot of coolant checked the belts and they look to have a good amount on them so I'm assuming my water pump gave out(cars at 125k previouse owner said that and pcv had been checked/ replaced by an earlier owner who knows). I Ordered the pump and all the gaskets/ 1 gallon of coolant. I know people say you can do it without going into service mode but have only seen it done on a6/ a7 3.0t. Any tips or recommendations? First time digging into the 3.0t but have work on a lot of my other vw's

[Jroyalty7]

It’s more likely that your SC intercoolers are leaking than the water pump on this platform. Any signs of coolant anywhere in the engine bay?


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[sacandagaD]

Noticed I've been losing a lot of coolant checked the belts and they look to have a good amount on them so I'm assuming my water pump gave out(cars at 125k previouse owner said that and pcv had been checked/ replaced by an earlier owner who knows). I Ordered the pump and all the gaskets/ 1 gallon of coolant. I know people say you can do it without going into service mode but have only seen it done on a6/ a7 3.0t. Any tips or recommendations? First time digging into the 3.0t but have work on a lot of my other vw's

Check out the FCPEuro videos on Youtube for S4 WP and T-stat replacement. Very helpful resource. Service position is pretty easy, and makes life so much easier to work on the front of the car.

[Nelson G]

Here are two sites to look at: https://blog.fcpeuro.com/how-to-repl...tat-b8-audi-s4
https://www.audizine.com/forum/showt...Removed-(Pics)
And you might want to purchase a MADDOX Cooling System Test and Refill Kit so you can check where the leak is coming from and it will help you refill the system.
https://www.harborfreight.com/coolin...sure+test+kits

[S4lty1]

The accessory belt had coolant on it it so that's why I think it's the water pump

[S4lty1]

Perfect! I was looking for some additional threads did find the fcp euro one and that was definitely helpful and just got a similar coolant system pressure test/ refiller

[S4lty1]

Any idea the size/ thread pitch of the bolts for service position so I can grab some longer ones to cantilever on?

[S4lty1]

If the water pump went do I need to replace the thermostat on these cars? I've seen mixed info

[Nelson G]

Considering you will have the supercharger off and will then have access to the thermostat why not? I would also change the crossover pipe as that was the source of a small leak in my car.

[SwankPeRFection]

Considering you will have the supercharger off and will then have access to the thermostat why not? I would also change the crossover pipe as that was the source of a small leak in my car.

Technically you don’t need to take the supercharger off at all to change the water pump. It can be done with just the belt off, pulley taken off the water pump and then you can get to all the bolts for it. Take those off and it pops right off the front of the engine. You do need to be in service mode to have good enough room, but I can easily be done that way if you’re only looking to change the pump.

[S4lty1]

Thats what I was planning to do, leave as much in place as possible. but nothing ever goes to plan so we'll see

[S4lty1]

So got it in service position and it looks like coolant it pooled below the thermostat/ vacuum line / coolant pipe slightly to the right and back. Any recommendations? Thought it was the water pump but the weephole doesn't look like is has coolant the belts are just covered

[S4lty1]

No coolant in the oil, no white smoke but it goes through Maybe a liter of oil every 5k which isn't to bad. So didn't think supercharger cores or pcv. Any ideas?

[a4lownslow]

Take the supercharger off, plug the two rubber coolant lines that go to the supercharger and pressure test the cooling system before taking anything else apart. This will eliminate guess work. Coolant pooled in valley Is either pcv leaking externally, coolant pipe above pcv. Or thermostat.

You have no symptoms of supercharge bricks leaks, so I doubt that is the issue.


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[Waffles_s4]

OP: posting pics on here would help a lot.

SC cores would leak directly into the cylinders as far as I know, so you would actually see coolant traces from the SC ports once u remove it. Do you have pics of that?

So it would be either thermostat (which u would see coolant around the thermostat housing itself, a coolant pipe (same story, u would see coolant around it) or the PCV (which u can take apart and inspect itself before buying parts.

Water pump wont leak under the Supercharger area, rather down towards the belts and even the belly pan.

[S4lty1]

https://www.audizine.com/gallery/dat...225_190919.jpg

[S4lty1]

[S4lty1]

[S4lty1]

First pic shows the water pump and coolant temp sensor dry, second shows coolant in the valley and third shows a coolant pipe that could possibly be a sign of leaking

[S4lty1]

Unordered for the coolant to get in the valley I'd assume it's that or the pcv? Super charger coors didn't have any burnt coolant either

[Mfryman1]

https://www.mcmaster.com/products/bo...length~125-mm/

10MM bolts for service position

[S4lty1]

Thanks, I grabbed some m10x1.5 120 to slide the front clip out on

[SwankPeRFection]

Could be the gasket on the thermostat causing the leak from the housing there or an issue with the PCV. Given how far in you are already, if the bolts are tight on that thermostat, I’d just go ahead and do the PCV and thermostat and new pipes for it… the big front one and the one that runs off the thermostat to the heater core. Knock it all out and then you’ve reset the clock on all that shit and don’t have to take the charger off again.

[Waffles_s4]

Or you can take both the thermastat and pcv off, check if there are leaks.

Guessing here but only symptom of a failed PCV would be 1) more coolant in oil, 2) after removing the PCV u would see coolant in there, 3) coolant on the outside of the PCV.

[SwankPeRFection]

Hey, I’m not saying it’s a failed PCV, but if you’re doing all that work to take the old one out, I sure as hell wouldn’t put it back in, I’d put a new one back in. They’re not that much… especially when you don’t know how old it is and since it’s a PITA to replace. Worse design Audi could have ever done with this engine… absolutely the worse decisions on engineering that.

[Waffles_s4]

Guess depends where you are and how much the parts cost. But say for $300USD for both I would change them.

[Nillious]

Hey, Worse design Audi could have ever done with this engine… absolutely the worse decisions on engineering that.

I agree. But I also think these cars have one of the cleanest and best looking engine bays of almost any modern car. They really did a good job hiding everything. My buddy has a q50 and if he removes the plastic cover it looks like a damn oil refinery lol.