Strange coolant problem

[Sparky001]

Hi

 

I have a Audi A3 8P 1.9tdi 2007 and have been having some strange coolant problems

 

It’s started out when driving a long and the low coolant light come on but temperature was fine, if I continue to drive the light would go off. However I am having to top up the coolant about 2litres a day now. 

 

It is has started to get worse as now driving on the motorway if I come to an incline and the engine has to work a bit harder the temperature climbs to 130. I ease right off and it reduces back to normal but the low coolant level light doesn’t not come on during this.

 

During the whole time the heater would only blow out hot air for about 5 minutes and then just cold air.

 

I have had it pressure tested and the garage said they could not find a leak anywhere, they tested it for the whole day. He said he had a mate who has the same problem and it was the cylinder head turning porous. I have googled this and I believe that this only happened to the earlier models of the 1.9 and 2.0 and the symptoms do not seems to be this but not sure.

 

I have changed the thermostat and water pump, flush the rad and coolant out.

 

I have read that it could be the EGR cooler having a leak and leaking into the exhaust but not sure.

 

There is no obvious signs of a blown head gasket , no smoke or bubbles in the top tank, or water in the oil and starts fine.

 

Anyone have any suggestions?

 

 

[Magnet]

SHello ? (Sorry, you don't give your name),

Sorry to hear of your problem. 

To be able to have a better chance of offering meaningful advise, a little more detail would be helpful.

Did you change the water pump and thermostat after the trouble started? If so, why water pump, since it is highly unusual for these to fail to pump water and cause such issues. Thermostat - did you use a genuine VAG replacement part? -  since there is always potential for aftermarket thermostats to be faulty. Similarly, what make water pump did you use. 

Have you thoroughly bled the coolant system ( with heater set on max. setting) to ensure you don't have any air locks? When the car is up to temperature both heater hoses should be at the same temperature to the touch. It is always good practice to squeeze all hoses (watching hands!) while the system warms up. 

2 litres a day is at least 20% of the system's capacity so that is really worrying.

Simple test to perform:-

Get the car up to temperature, and get an assistant to rev the engine and hold it at a steady 2000rpm for at least 3 to 4 minutes while you observe any smoke from the exhaust. Any? Is so, what colour? 

Perhaps you can let us have the answers to all the above, at which point it may be possible to suggest a further simple thing to check/replace as a trial.

Kind regards,

Gareth.

 

[Envy]

That volume of coolant has to be going somewhere and as Gareth above says - look for the obvious signs. Steam out of the exhaust, pooling around the EGR etc. 

With the engine warm do you get the sweet smell of antifreeze wafting out? Evan in the cabin if the heater matrix was leaking?

EGR, head gasket or porous head would be my train of thought going for the cheapest first although you say the coolent system has been pressure tested and worked out ok. Did they carry out the pressure test hot and cold?

 

[Ellensaudi]

Hello, I too am a newbie to this forum but felt I needed to share my recent car problem.

i have a 2007 A4 convertible. I’ve owned it for 4 years and apart from regular servicing I’ve never had the coolant light come on. About 6 months ago, the light came on and I duly topped it up with water. I drove (Regular town driving) for about 3 months and only had the light come on one more time. Within the last month, I was lucky if I drove more than a mile before the light come on. Each time I checked, surely enough the tank was empty. I asked the garage who immediately said it was the head gasket. I really wasn’t convinced as I wasn’t using oil, the oil wasn’t foamy or manky. I wasn’t overheating and I had a pressure test done which were all ok. ...... my lovely husband who has a mechanical background wasn’t convinced either. 

‘He discovered that it was a small plastic connector that sits at the back/bottom of the engine. The part number I can see is 06D121133a, it’s called a coolant hose flange. Cost about £12. My husband fitted it but it took around 4 hours because it was so difficult to get to. It’s fixed the problem 100%

The one he took off explains the leaking, it was corroded and looked like it had melted. 

 

[Sparky001]

Update:

 

After taking it it to a VAG specialist for diagnosing they informed me that it was either cylinder head cracked or head gasket as the the coolant system was pressurising.

 

Will I put up with it for 6 months and after completing my Defender 90 rebuilt I started and removed the head from the A3 and just after getting the head off and no obvious sign on the gasket or head and continued to strip if down to get it pressure and crack tested. However having removing the EGR I wondered if the EGR cooler had a leak and after blowing in one end and my finger over the other it didn’t hold air and could hear it releasing air. It was confirmed after using water hose and I have a pin hole leak which now explains a lot just a shame that i had to strip down the head to discover the real problem but getting head tested still to confirm!!!

[cliffcoggin]

Glad you got it resolved. I am surprised the garage pressure test didn't reveal the leak from the EGR cooler considering how easily you found it after stripping the engine.