A3 sportback 1.6 overheating issue

[Nicholas]

Hi guys I hope someone can help 

I have an A3 2010 sportback 1.6 tdi

Basically going around town perfectly fine even at temperature,  it doesn't rise. 

The minute I take it on the motorway after about 7 miles or so it starts to over heat. But its not loosing water if anything the light would come on the dash saying "no coolant please pull over" so I checked it but the coolant was higher than it normally was, so I thought it was the thermostat sticking so I had it changed, still the same issue, garage took it for a drive and advised that the radiator at temperature was stone cold , but at the same time told me its over pressuring pipes was so hard to squeeze, so I bought a new over flow bottle cap (cheap possible solution) and got the garage to change the rad as they explained it looked rusty. 

Again still over heating with pressure in system. 

Now they are advising it could be a split head, gasket , or might possibly the water pump 

Had the water pump and Cambelt done 2.5 years ago and only done 15000miles since. 

Downfall of the head and gasket is that I thought if that was cracked or gasket is going then surely I would be loosing water ? Which I am not ? And also if it was the head or gasket surely it would overheat straight away driving it around town ? It seems as if I put my foot down and go at a higher speed it pressurise alot In the system which causes it too over heat ? 

 

Can anyone shed any light on this please or if they have come across the same issue as now I am completely stumped and really don't fancy forking out 1500 odd on having the head sent away to get checked and possibly skimmed and also all new gaskets. 

[cliffcoggin]

Nicholas.

If I understand you correctly the engine is overheating while the radiator stays cold and there is no loss of water. If so there is clearly no circulation of water. That may be caused by:

[1] Blocked water galleries in the engine, (very unlikely but not impossible).

[2] A defective pump, (also unlikely as you it done recently).

[3] A defective thermostat, (possible if it has not yet been changed.)

[4] An air lock in the cooling system. If I was a betting man I would put money on this being your problem. It often occurs after work on the cooling system and can be a devil to get rid of. Search online and you will find various suggestions of ways to resolve the problem.

I am also equally certain that the problem is nothing to do with the head gasket or a cracked head, and I am surprised your garage even suggested it. Time to find a new mechanic I believe.

[Magnet]

Hello Nicholas from the Homeland,

Apologies for boring, but my first port of call would be to return to the thermostat and replace it with a genuine VAG one - if that isn’t what you used as a replacement. 

Kind regards,

Gareth. 

[Ashleyjay]

Hi. Im having the same issue on my a3 2.0. Its OK when I'm driving around town but when on motorway temps going to 130 and the water tank starts to bubble and steam comes out if my engine. One mechanic has said its my matrix pipe thats blocked and another saying head gasket or top head. Its going back to matrix quote garage to check head gasket. I have no gunk in any tanks so I'm really hoping it's the matrix.  I ve had new water pump and cam belt along with thermostat so its not them . Its awful isn't it 😩x

[Magnet]

I would suggest you don’t assume that ‘new’ = serviceable, until proved to be so. 

Not wishing to appear critical, but why allow an engine to run its coolant up to a totally unacceptable 130 degrees, and allow steam to come from the engine, before deciding to slow down/pull over/get off at next junction? 

Chances are it is now likely that you have done some mischief to the engine/ coolant system, and that this possibly recently caused issue will be taken to be the reason for the original overheating - when it may not have been.

Kind regards,

Gareth. 

[cliffcoggin]

Ashley.

Repeating your problem in this topic while ignoring the questions and suggestions in your own topic is pointless, so I shall withdraw from both.

[Ashleyjay]

Wow Cliffeclogging how rude. As I explained in MY post I'm a woman and know nothing about cars. I was just letting another person know that my car is doing the same so could be a common thing with a3s. No need for your comment at all !

[Ashleyjay]

And you put this link to look at on my original post so don't understand what your trying to get at ??