# Coolant Leak; Audi TT



## Scigano (Mar 10, 2011)

I think I may have sprung another coolant leak in my TT 180 Quattro. 

We found the first one when doing an oil-change. My boys at my Audi/VW specialists, Axis Motoring thought it to be the coolant flange since that seemed pretty stained with pink coolant. It was on my transmission and such too, making for the characteristic sweet smell of burning coolant. So I've got a fresh one of those.

Now I thought I smelled that scent again many months later. So in I went, took out all the stuff in the way and low and behold:





































(pretty sure *this* guy is the culprit now.

I had wiped most of the pink crud by the time I took these pictures (to make sure this is fresh stuff n' not from before, but I'm fairly sure it is), but it was on the tranny and a few drops on the driver-side axle.

Interestingly, neither with the flange leak or this one, the engine has never overheated. The only indicators I get are either the smell or when my tech friend goes, "you see this pink stuff dripping from your undertray? :facepalm: " 

Today, I turned it on after checking it out n' putting it back together, let it warm up, then spent a few minutes revving it into 5-7 PSI to work it up a bit at stand-still to see if it would heat up too much, but it did't. Never has in traffic either.

I guess neither was a severe enough leak to compromise the engine too much (n' I live in Florida). 

In summation: can I get the skinny on *what that particular hose is called* so I can get ahold of a replacement? Additionally, does the 1.8T come with a low-coolant-level sensor? or just a timer for every so often it thinks it should be serviced? (in case it ever _does_ get too low)


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## Dub-Nub (Sep 27, 2005)

first of all, awd or fwb version.

second, the hose should have a part number.

third, get a pic of both connetion ends of that hose.


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## Scigano (Mar 10, 2011)

Dub-Nub said:


> first of all, awd or fwb version.
> 
> second, the hose should have a part number.
> 
> third, get a pic of both connetion ends of that hose.


Neither. It's a Quattro with an ATC block. Fatter 20 mm con-rod wrist pins, no VVT at start up.

It plugs into the same fatter hose that goes to the coolant temp sensor. The other side goes into the block. I'll get another photo later if need be.


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## Scigano (Mar 10, 2011)

*bumpety-bump-bump*

Haven't gone back yet for a second look, but anybody had this one break n' know it by just the sight of the bugger? I'll check ECS tuning in a bit to see if they have a diagram to assist.


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## Scigano (Mar 10, 2011)

Okay. I went back to take a better look at the hose where I think the leak is coming from and trace where it connects at its two ends.










it has one end here, where it connects in a T-fashion into a hose that I can't very much see where it goes in either direction (though it heads towards the rear of the car suspiciously in the turbo-direction).

This is where coolant seems to seap out some. Because it connects into that other hose, I can't say for sure if it's the marked hose that's leaking, or the one it goes into (but alot of the coolant gunk is on the pinch-clamp for the marked hose if that points to it).










It then connects here into what I think is the upper radiator hose (which leads to the coolant flange, among other things, like I noticed before).










Here's the only information printed on the marked hose that I could find










I'm not sure if any of that is the part #, but I hope so, because I couldn't see anything else.










Here's a photo I found on another post here on Vortex. I can't say for sure that these are for my exact version of the 1.8T. Because of where it leads to on one end to the upper radiator hose, I think my hose in-question is some version of the hose circled in red (i get the feeling mine may be longer, but the connecting location's the same). It's connected to the same, fat hose that goes into the coolant flange and temp sensor location (the upper radiator hose, right?).

okay. what is *that* hose called? Is it part of some coolant feed to the turbo or something else? Thank you for any insight n' help!


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## Scigano (Mar 10, 2011)

It's a water hose. 

http://www.vaglinks.com/Docs/Catalogues/ETKA_Audi_2000_TT_Coolant_System_PartNumbers.pdf

It's the ETKA parts catalogue for the 2000 Audi TT, but the thing is the numbers don't match up exactly on this catalog (but neither do the engine codes: it keeps saying *APX* or *BAM*, when my car either came with an *ATC* - mine - or the *AWP*); I get as far as 8N0-121-*** before the last three digits aren't the same ones for any of the ones listed. I need 8N0-121-096, but they're all:

14 *8N0 121 088 *water hose
(flange > oil cooler >
water pipe)

(17/16) *8N0 121 086* G water hose
for vehicles with anti-slip
regulation -asror
for vehicles with electronic
differential lock -edl-
F 8N-Y-036 001>>* 1 APX

(17) *8N0 121 086 F* water hose
electronic stability
programme -esp-
F 8N-Y-036 001>>* 1 APX

(17) *8N0 121 086 M* water hose
for vehicles with electronic
stability program -esp-

So now I need to see if I can find my correct water hose (car gives me so much lip, even after I buy it such nice things ) Before I got this far, one of the guys I trust at the shop said he thought it had something to do with an oil-cooler.

EDIT: I typed the part # into ECS's search engine and it came up with five water hoses (no pictures). There's an A-version, B-version, F-version, G-version, and an H-version.

If it's the last three, they say those ship in 1-3 days. If it's an A-or-B-version, it's a special order piece. ETA: January 6th :facepalm: . 

So either I hope it's an F, G, or H-version or that one of the last three is interchangeable with the first two. 

Anybody know how I can tell if the last letter isn't printed on the part?


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## l88m22vette (Mar 2, 2006)

BAM is the euro code for the 225TT, so you'd want the APX hose...try to get ahold of someone at ECS, they should be able to tell you which version/revision you will need


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## Scigano (Mar 10, 2011)

Yeah, I sent them an e-mail already.

On the ETKA catalogue, I couldn't find an exact match for the APX anyway, n' there are a few hoses that they both share. Maybe I should search 8N0-121-096 vs. its European code (if anyone has published anything like that).


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## Scigano (Mar 10, 2011)

Update: I went to both an Audi and a Volkswagen dealership to see if I can get any insight as to what is the pipe I have to get:

The 8N0-121-096 piece has been replaced (again, 10 years old). The new piece is 1J0-121-096 (they told me the H-revision at the dealerships, but online like at ECS, they have "BK" or "BR" versions).

ECS Tuning says it isn't in stock, but can ship in 1-3 days. Another version of the 1J0-121-096 runs coolant to the transmission cooler on automatic Mk.IV VAG cars, but I don't know if it does the same thing on my manual TT. ECS Tuning lists the automatic's cooler hose for that, but the other hose just says "HOSE", so I don't know if it also runs to a transmission cooler for 1.8T manuals.

They have a version of the automatic cooler pipe in stock already, but it doesn't look exactly the same (close, but not the exact), so I don't know if they're interchangeable (likely not I'd guess :facepalm: for being stupid).

Got to get the hose n' a jug of Audi/VW coolant.

Luckily, I the car still doesn't overheat (weather was between 70s n' 90s). I think I may have smelled s'more coolant spill onto hot bits (I wiped most of it off when I went looking for the leak).


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## Scigano (Mar 10, 2011)

http://www.ecstuning.com/Search/1j0121096/ES307191/

I think thisnis the hose that needs replacing. Anybody know what this supplies water to. It may be an adaptor hose. Something for routing coolant from the radiator hose to the water pipe - the hose that imsaw running along the block by my transmission? - (whatever the difference between a *radiator pipe* and the *water pipe* is).


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## Scigano (Mar 10, 2011)

*bump* don't want this to retire to the back-of-the-bus yet. Tomorrow, I'm going to try scoring the hose and see if this can all be done w/ by Tuesday.


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## Scigano (Mar 10, 2011)

Question: how many of those big jugs of Audi/VW coolant do I need to properly refill my cooling system after replacing this hose? Thanks!


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## Dub-Nub (Sep 27, 2005)

Scigano said:


> Question: how many of those big jugs of Audi/VW coolant do I need to properly refill my cooling system after replacing this hose? Thanks!


1 should be fine, 50/50 mix will be plenty.


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## Scigano (Mar 10, 2011)

Thanks Dub-Nub :thumbup:


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## Scigano (Mar 10, 2011)

Update: well, it turns out it was the coolant flange. again. All the discharge I saw on the coolant-to-water pipe hose was just dripped from that. So _both_ have been replaced. 

(why must it be such a leaky mistress?). Issue done with (hopefully).


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## ryanj (Sep 15, 2008)

Coolant leaks are almost always a result of over heating. I know you said its not indicating that its over heating, but I am willing to bet that you have at least 1 maybe even 2 burned out cooling fans making your engine run hotter at times and stressing out your system over time.


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## Scigano (Mar 10, 2011)

But the fans turn on.


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## The36Chambers (Aug 21, 2009)

To answer your second question, there is a low-level switch inside your coolant reservoir. If you look at the bottom of the tank, you'll see a two-pin harness connected to it. As soon as your coolant level drops below that float switch, you'll get a warning on your dash.


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## Scigano (Mar 10, 2011)

That's good to know. Now dangerous amounts of coolant-loss can't sneak up on me :laugh:


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## Scigano (Mar 10, 2011)

When I first bought the car, I noticed that sometimes when I turned the car off, the fans would stay on. I got worried it could have been an issue, but I was told online that it was normal for the car to do that on hot occasions to keep it cool and maintain an appropriate temperature.

Since being told that, I thought it was okay, but I wanted to bring it up again just to be sure. I'd imagine this would only work if something continued to circulate the coolant around the motor even after the engine is turned off. Is there something that does that?

Also, on a related issue, I have a FMIC and recently thout maybe an upgraded radiator core would be a bad idea. I found this on ECS Tuning:

http://www.ecstuning.com/Audi-TT_MKI-Quattro-180HP/Engine/Cooling/ES2102240/

Is this an upgrade over my existing radiator (ECS lists it under Audi TT 180 Quattro just like my car), or do US market cars already come w/ the larger core and the only upgrade left afterward is the Mishimoto radiator ECS also retails?


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## jamesd692000 (Jun 19, 2012)

i am having the same problem , with my 2000 1.8 TT 

you said the flang needed to be replaced also do you have part # or pic of it 

thank you


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## Scigano (Mar 10, 2011)

jamesd692000 said:


> i am having the same problem , with my 2000 1.8 TT
> 
> you said the flang needed to be replaced also do you have part # or pic of it
> 
> thank you


Sorry I didn't reply to your post sooner, chief — here's a link to ECS tuning's retail page for it:

http://www.ecstuning.com/Volkswagen-Golf_IV--1.8T/Engine/Cooling/ES279315/ 

It would be on the driver side of the engine block and have the coolant temperature sensor sticking out of it (easily seen if you have the green one exchanged for the faulty, earlier black one).


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## Slimjimmn (Apr 8, 2006)

and FYI, always use new screw clamps on cooling system stuff. Dont reuse those crappy spring clamps, they leak


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## MEDEL514 (Jan 12, 2002)

Glad I found this thread! I'm having a coolant leak too (no puddle) on my 01' Audi A3 1.8tqm. Sometimes when I start it, I can smell the sweetness, and go to the engine bay and see a little steam coming from the back of the engine where the turbo is, but there is never any resudue or a puddle on the ground. I hope I can trace it down because I'm loosing coolant every couple of days now... :banghead: 

On a side note, I remember there was a .pdf file of the Bently Manual for the 1.8t online (free, maybe illegal) because the link I had saved doesn't work anymore. Anyone else have the Bently availible for (free) download??


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## Scigano (Mar 10, 2011)

Other than the coolant feed for the turbo itself, how many other lines are there on the exhaust side of the motor that can leak? If there's just the one — than that leak can be at the connection between the line and turbo. The steam would be indicative of the coolant hitting hot engine bits and evaporating (certainly producing a strong example of the coolant smell).


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## Slimjimmn (Apr 8, 2006)

block to turbo and turbo to timing belt area coolant hose.


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## chaldowhiteboy (Jun 14, 2010)

THANK YOU for this thread! I swear I have been looking everywhere for that dang hose! I don't even know how I finally found this thread. Here are some pictures to share my pain.. please ignore the mess 

Just for reference-
Mine is also a 2000 TT 180Q ATC engine code


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## Scigano (Mar 10, 2011)

I think you need this one then, mate. 

http://www.ecstuning.com/Search/1j0121096/ES307191/


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## chaldowhiteboy (Jun 14, 2010)

Scigano said:


> I think you need this one then, mate.
> 
> http://www.ecstuning.com/Search/1j0121096/ES307191/


Definitely, thank you. :beer::beer:

It would be nice if someone made these hoses in silicone. You didn't stumble over any during your search, did you?


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## Scigano (Mar 10, 2011)

I'm afraid not, I got it straight from the dealer.


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