Audi A3 2ltr TDI losing water - Help!
Audi A3 2ltr TDI losing water - Help!
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buzzer

Original Poster:

3,621 posts

271 months

Monday 15th February 2010
quotequote all
my 2003 Audi A3 TDI is losing water at the rate of a pint every couple of weeks... its always lost a bit (over the last 20k miles - its done 100K overall)

I cant see any external leaks so i am fearing a head gasket or worse?

Any one offer any advice?

In particular I am waiting for Paul the "tame Technician" to comment as he gives out sound engineering advice based on real world experience!

If it is a head gasket, how easy/difficult are they to do? do i need any special tools?


thanks in advance!

Cupramax

11,007 posts

283 months

Monday 15th February 2010
quotequote all
Number of things to check really, first pressure test the cooling system to see if it is leaking anywhere under load. Next compression test each cylinder as if its not leaking externally it'll be going into one of the cylinders, or worse into the oil. Check the dipstick, does the oil look clean or is it like mayo? If its like mayo the water is geting into the oil lines somewhere. You may need to have the head off as it could be a head gasket...

buzzer

Original Poster:

3,621 posts

271 months

Monday 15th February 2010
quotequote all
the oil is clean, so its not going into the oil. it also runs well and ticks over smooth (as much as they do...) so i dont think its a compression issue.

I have also had a sniffer test on the coolant to check for combustion products / gass coming ou in the header tank, but with no luck. They did say however that the head gasket has to be welll gone for it to show up with this test....

Any other suggestions?

BoraBora

143 posts

201 months

Monday 15th February 2010
quotequote all
if its a slow leak it could just be leaking out a hose under pressure ?, have you put any RADWELD into your cooling system yet ?, that sorted my problem out.

Tame Technician

2,467 posts

235 months

Monday 15th February 2010
quotequote all
EGR coolers leak internally on the A3 2.0TDI.


buzzer

Original Poster:

3,621 posts

271 months

Monday 15th February 2010
quotequote all
Thanks, looks like I will replace the EGR cooler first. Can I buy just the cooler? Is it easy to fit?

Tame Technician

2,467 posts

235 months

Monday 15th February 2010
quotequote all
You can buy it, you need a few gaskets too.

No its not that easy to fit, sorry, its right at the back of the engine bay, under the inlet truning.

Looks like this.

Number 7


The top part


Edited by Tame Technician on Monday 15th February 21:20

buzzer

Original Poster:

3,621 posts

271 months

Monday 15th February 2010
quotequote all
Gulp, looks expensive! How much do you reckon? Also, what are the chances of it being this?
Go on, take a stab, I won't hold you to it!

Tame Technician

2,467 posts

235 months

Monday 15th February 2010
quotequote all
90%. We do quite a few and keep two instock. You can take the EGR cooler off and have a look inside, if there is no cooland residue, put it back on. Never done a head gasket on 2.0TDI for coolant loss. We have had a handfull of porus heads, but they tend to be from new and fixed early while the car is still under waranty, not develop after 100k miles.

Cant recall the cost, I try and find out tomorrow.

00161wj

566 posts

239 months

Monday 15th February 2010
quotequote all
Cant just be guessing at things like egr coolers that are 300 odd quid.
You need to PROPERLY check over the cooling system paying special attention to the bottom of the radiator on the ends as they go on these.
If no leak can be found then you need to first check the cylinder head. Remove the EGR cooling pipes and join the cooling pipes together (blocking off the EGR cooler from the system). Then pressurise the system with an appropriate tool and leave overnight if possible. Then start the car in the morning and if the engine hydraulics and jumps about you have water entering the cylinders and the heads had it.
If it starts ok its the EGR cooler.

Tame Technician

2,467 posts

235 months

Monday 15th February 2010
quotequote all
Agreed pressure testing overnight is the best way to check the entire cooling system. But given the effort involved in isolating the EGR cooler water tight enough for a pressure test, I personally would just take it off and look in there for coolant residue.


buzzer

Original Poster:

3,621 posts

271 months

Tuesday 16th February 2010
quotequote all
not looking good... i have taken the cooler off and there does not appear to be any water residue in there? its just matt black? guess i am not sure what i am looking for though...

I have just filled the cooler with some soapy water and will pressure test it shortly once the water has settled and there is no more bubbles coming up. my fear is that it may only leak when its hot, and i presume these get very hot?

Any where else i look?

Tame Technician

2,467 posts

235 months

Tuesday 16th February 2010
quotequote all
Part of the cooler is a bypass flap (has a vacuum actuator on it) take this bit off, if you havnt already, and shine a tourch inside, if the EGR cooler is faulty there will be white/pink scale type resedue or visable wetness amongst the normal matt black soot.

We did one today they are £220+ Vat.

Id ther is definatly no evidnece of coolant insude then is it somthing else.


buzzer

Original Poster:

3,621 posts

271 months

Tuesday 2nd March 2010
quotequote all
Thought i would update....

I have pressure tested the system and done a sniffer test with the sensitive fluid. (sykes kit) while it was hot and under pressure i looked for leaks, systematically checking every possible place it could leak... no leaks. over an hour it didn't drop any pressure.

Over night it lost a couple of pounds but that could be from the test kit. next morning it started fine. the sniffer test showed nothing.

I am at a loss on this one....

Must admit i have added some K Seal to the system and will test for water loss over the next week or so.

Any more suggestions appreciated, otherwise if it still loses water... its off to be traded in!

Tame Technician

2,467 posts

235 months

Tuesday 2nd March 2010
quotequote all
Its normally the EGR cooler, if it isnt that (and it sounds like you've had a good look at it), then its normally the cylinder head.

We probably do a 2.0TDI head 2 or 3 times a year for coolant loss, so it can happen. EGR coolers its more like 1 or 2 a month. We see around 45 cars a day to put into perspective.

Given the cost of replacing the head, I'd just top it up every week or so.


CrispDust

4 posts

190 months

Sunday 30th January 2011
quotequote all
My Altea 2.0 BKD is loosing coolant - about 200ml every week/200 miles.
I did an overnight pressure test last night - set at 20 PSI, it dropped to 15 PSI after about 4 hours but didn't drop any further over next 5 hours. Some coolant loss noticed in level of header tank - max to minimum. Car started absolutley fine but had lots of white steam, possibly slight smoke for first couple of miles (didn't smell like oil/diesel burning) and then stopped. Ran fine for 2 x 70 mile motorway trips. Oil is fine, no mayo evident and no oil usage. Power level fine. Does this look like an EGR coolant leak?

Tame Technician

2,467 posts

235 months

Monday 31st January 2011
quotequote all
CrispDust said:
My Altea 2.0 BKD is loosing coolant - about 200ml every week/200 miles.
I did an overnight pressure test last night - set at 20 PSI, it dropped to 15 PSI after about 4 hours but didn't drop any further over next 5 hours. Some coolant loss noticed in level of header tank - max to minimum. Car started absolutley fine but had lots of white steam, possibly slight smoke for first couple of miles (didn't smell like oil/diesel burning) and then stopped. Ran fine for 2 x 70 mile motorway trips. Oil is fine, no mayo evident and no oil usage. Power level fine. Does this look like an EGR coolant leak?
Internal leak like that can be either pourus head, head gasket or EGR cooler. You dont always get the lack of power, over heating mayo etc with head problems, but its still good you not having those issues.

You can take the EGR cooler off and inspect it for the price of a few gaskets, less than £10. You will be able to look inside the cooler and see if there is coolant residue. IF there is it needs replacing.

buzzer

Original Poster:

3,621 posts

271 months

Monday 31st January 2011
quotequote all
I never resolved this problem on the Audi... The EGR checked out OK so It looked like it was a porous head on the car. We have a cylinder head specialist not far away and I went to see him with the car. he said that he sees quite a few of these and even when he pressure tests them, they don't show up any leaks as it pourosity rather than cracks.

This guy recently checked a BMW 728i head for me, he thoroughly cleans the head, blanks off all the waterways, and then drops the whole head into a vat of boiling water. he then pressurizes it and looks for bubbles... Mine was OK but the Peugeot head he had just taken out had several cracks... some pictures on the link below.

http://www.pistonheads.com/gassing/topic.asp?h=0&a...

Back to the Audi... Over a few thousand miles it was steadily getting worse, so I tried some K-Seal. this slowed water loss down somewhat but that's a bodge really...

As it also needed a clutch and dual mass flywheel and a few other jobs, and it had been the most unreliable car we have ever had, I traded it in.

Not sure if the Tame Technician will agree on this but the 2.0 engine does not seem to be VAG's best...

Edited by buzzer on Monday 31st January 08:16

CrispDust

4 posts

190 months

Monday 31st January 2011
quotequote all
Makes my Alfa V6 busso look positively reliable

buzzer

Original Poster:

3,621 posts

271 months

Monday 31st January 2011
quotequote all
CrispDust said:
Makes my Alfa V6 busso look positively reliable
I wouldn't go THAT far.... biggrinbiggrinbiggrinbiggrinbiggrinbiggrinbiggrin