Coolant

2.9 V6 24v TFSI - 444 bhp
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elchet
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Coolant

Post by elchet » Mon Mar 13, 2023 12:43 pm

Not sure if I have a (slow / undetected leak), but has anyone else experienced coolant levels dropping over time?

I had an interim service at 4 rings in October, and just checked coolant while topping up washer fluid and the float was low.

Mixed 1:1 VAG coolant with distilled water and it took about a litre to get the float to pop all the way up again. I'll keep monitoring of course but seems fishy.
2018 B9 RS4 Daytona Grey

Elpeterol
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Re: Coolant

Post by Elpeterol » Tue Mar 14, 2023 8:10 pm

This came up some time (couple of years!) ago my car used a little coolant in the first few months but has since settled down.

elchet
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Re: Coolant

Post by elchet » Wed Mar 15, 2023 3:14 pm

Good to know, thanks. This is around 40k miles though so would hope everything is fully bedded in now!
2018 B9 RS4 Daytona Grey

Rusty Racer
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Re: Coolant

Post by Rusty Racer » Wed Mar 15, 2023 8:53 pm

Maybe a pressure test is required?
2018 RS4 B9 Carbon Edition
2014 RS4 B8

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rjwojcik
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Re: Coolant

Post by rjwojcik » Thu Mar 16, 2023 8:37 am

What's your oil like?
Current:
2018 RS4 - Navarra Blue / Black
Gone:
2016 A6 BiTDI - Midnight Blue / Black
2016 Golf GTD with a "lot" of toys
2016 M3 CP - Mineral Grey / Black
2009 135i - Le Mans Blue / Black

elchet
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Re: Coolant

Post by elchet » Fri Mar 17, 2023 2:55 pm

I haven't had any oil related issues. Everything looks clean around the cap. No comments on fluids at all at the last interval, except that it's due a sport diff oil change so I'll get that done and enquire about coolant on the same trip I guess.
2018 B9 RS4 Daytona Grey

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rjwojcik
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Re: Coolant

Post by rjwojcik » Sat Mar 18, 2023 8:38 am

So hopefully your coolant isn't mixing with the oil then...
Current:
2018 RS4 - Navarra Blue / Black
Gone:
2016 A6 BiTDI - Midnight Blue / Black
2016 Golf GTD with a "lot" of toys
2016 M3 CP - Mineral Grey / Black
2009 135i - Le Mans Blue / Black

Jools
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Re: Coolant

Post by Jools » Tue Apr 11, 2023 8:31 am

While diagnosing another fault I noticed that I had lost about 350ml of coolant. Roughly 200ml below Min.
There are no visible external leaks to be seen any where.
I decided to check the intake system after seeing a YouTube video on an RS with a leaky charge cooler and voila! I have a small weap of coolant into the charge cooler that I found by removing the return air pipe from the charge cooler to the throttle body and looking at the side and bottom of the heat exchanger element. There is a small weap of water from the elemet and a pool of coolant at the bottom of the charge cooler. There are also signs of small amounts of coolant on the inside of the charge pipe and throttle body butterfly.
It looks like I've caught it early and will be replacing it ££££

Rusty Racer
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Re: Coolant

Post by Rusty Racer » Tue Apr 11, 2023 8:17 pm

Good job 👍
2018 RS4 B9 Carbon Edition
2014 RS4 B8

elchet
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Re: Coolant

Post by elchet » Thu Apr 13, 2023 2:52 pm

Jools wrote:
Tue Apr 11, 2023 8:31 am
While diagnosing another fault I noticed that I had lost about 350ml of coolant. Roughly 200ml below Min.
There are no visible external leaks to be seen any where.
I decided to check the intake system after seeing a YouTube video on an RS with a leaky charge cooler and voila! I have a small weap of coolant into the charge cooler that I found by removing the return air pipe from the charge cooler to the throttle body and looking at the side and bottom of the heat exchanger element. There is a small weap of water from the elemet and a pool of coolant at the bottom of the charge cooler. There are also signs of small amounts of coolant on the inside of the charge pipe and throttle body butterfly.
It looks like I've caught it early and will be replacing it ££££
Have you got a link to that YouTube video? Definitely something I want to check too!
2018 B9 RS4 Daytona Grey

Jools
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Re: Coolant

Post by Jools » Thu Apr 13, 2023 10:17 pm

Check out Vag Technic on YouTube. They are dealing with all sorts of RS wowes :?
I've attached a few pic's inside my intake system, one shows a drop of liquid on the butterfly of the throttle body.
PHO00007.JPG
Then a splt screen of the side of the charge cooler core with liquid running down it (LHS) and you can just make out the reflection of a small puddle at the bottom of the charge cooler case on the RHS.
PHO00015.JPG
I also found some on the sides of the two delivery pipes into the inlet manifolds.

I'm looking to see if the water matrix can be replaced as a new OEM unit is £1200, an uprated after market one is £2000 and a full after market charge cooler & its radiator is £3000 (Stage3)
I figure if I can refactor it for maybe £400 it could be forth running a part exchange scheme.
Apparently the main problem is getting the air side to seal correctly after you have had it apart as it's running at upto 2 bar depending on your tune if you have one.

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RS Owner
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Re: Coolant

Post by RS Owner » Thu Apr 13, 2023 11:43 pm

Jools wrote:
Thu Apr 13, 2023 10:17 pm
Check out Vag Technic on YouTube. They are dealing with all sorts of RS wowes :?
Bear in mind the channel called "VAG Technic Car Abuse" https://www.youtube.com/@vagtechniccarabuse4837
The TLDR is that VAG Technic might not be a reliable source.
:assflash:
Current : 2018 F5 RS5 (Let's Fire Up the Quattro)
Gone : 2017 M3 CP
Gone : 2007 B7 RS4 ( :kissmyrings: )

Jools
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Re: Coolant

Post by Jools » Sat Apr 15, 2023 10:26 pm

I am aware of the complaint against the guys at Vag Technical and I do not condone there actions or driving.
Did that chap ever post an indepentant engineers report on his engine failure, it would make interesting reading?
I am not promoting or commenting on there work but was merely pointing out they are one of the few channels to post the problems they have come across with specifically the RS V8 and V6 engines, I'm sure Audi won't be posting any teardowns any time soon. Most of the videos out there are on how to make your RS go faster, not on how to mechanically fix it.
Do you chance your arm with an Audi specialist non-dealer garage or let your local the Audi dealership 'service center' super tech at £200/hr suck through his teeth and say 'you need a new engine mate' and he might have been on a course on how to do an engine swap 18 months ago!
I'm sure RE Performance would be a good bet, but probably more expensive than Audi, but then It would be better built than by Audi!
It's all horse for courses, if we will insist on driving complicated expensive performance cars and gripe at dealer prices when it goes horribly wrong someone will always be there to step in to fill the gap and make a buck along the way.
The world ain't always shinny!

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