Bought myself my first A2 ( Y reg 1.4 Tdi 75) a few weeks back and was loving it until the first time I took it up to motorway speed.
The Problem -
After about three minutes doing 70mph the temp gauge was up to 100 degrees and though I immediately dropped my speed, the temp continued to rise and hit 110 degrees before I found a safe place to pull over.
Suspecting a head gasket failure I took it to a garage for a combustion gas leak detector test. This came back negative which gelled with the fact there was no sign of any emulsion in the oil.
The mechanic thought it was probably a stuck thermostat. And when the old thermostat was removed it did reveal a lot of gunk build up, so that seemed a good call at the time.
Unfortunately fitting a new thermostat and flushing the system had no effect and the problem remained.
The mechanic decided the next thing to do was replace the radiator with a new one but once again it made no difference at all.
We are now at the head-scratching stage.
Symptoms -
I can drive all day long at speeds up to 50mph and the temp will never exceed 90 degrees.
If I push it to 60mph it might start to exceed 90 degrees but very slowly.
If I push it to 70mph the temp will very quickly increase unless I back off my speed.
If I drop my speed to 40 mph the temp will come back down quite quickly.
Other symptoms -
I am losing coolant at the rate of about one litre for ever hundred miles travelled.
And that is the case even when the temp is maintained at a steady 90 degrees.
Note: there is no sign of any leaks anywhere that I can find - no puddles, no drips, no staining or discolouration.
Once up to temperature the bottom hose, while not cold, is markedly cooler than the top hose.
Most puzzling -
Even after being parked up for 48 hours the header tank is holding enough pressure to spurt coolant when the cap is released.
The latest -
The mechanic is now saying he suspects it must be a cracked head.
In his opinion this would be a crack that is allowing coolant into an exhaust passage.
My question -
Does the mechanic's suggestion that it's a cracked head leaking coolant into the exhaust system sound correct?
Could there be any other cause for the symptoms I have described?
Assuming it is a cracked head, is the next thing to try is a Holts Wondarweld treatment?
That was the mechanic's suggestion of what needs to be done next (he knows I can't afford to replace the head).
What do people on here think?
The Problem -
After about three minutes doing 70mph the temp gauge was up to 100 degrees and though I immediately dropped my speed, the temp continued to rise and hit 110 degrees before I found a safe place to pull over.
Suspecting a head gasket failure I took it to a garage for a combustion gas leak detector test. This came back negative which gelled with the fact there was no sign of any emulsion in the oil.
The mechanic thought it was probably a stuck thermostat. And when the old thermostat was removed it did reveal a lot of gunk build up, so that seemed a good call at the time.
Unfortunately fitting a new thermostat and flushing the system had no effect and the problem remained.
The mechanic decided the next thing to do was replace the radiator with a new one but once again it made no difference at all.
We are now at the head-scratching stage.
Symptoms -
I can drive all day long at speeds up to 50mph and the temp will never exceed 90 degrees.
If I push it to 60mph it might start to exceed 90 degrees but very slowly.
If I push it to 70mph the temp will very quickly increase unless I back off my speed.
If I drop my speed to 40 mph the temp will come back down quite quickly.
Other symptoms -
I am losing coolant at the rate of about one litre for ever hundred miles travelled.
And that is the case even when the temp is maintained at a steady 90 degrees.
Note: there is no sign of any leaks anywhere that I can find - no puddles, no drips, no staining or discolouration.
Once up to temperature the bottom hose, while not cold, is markedly cooler than the top hose.
Most puzzling -
Even after being parked up for 48 hours the header tank is holding enough pressure to spurt coolant when the cap is released.
The latest -
The mechanic is now saying he suspects it must be a cracked head.
In his opinion this would be a crack that is allowing coolant into an exhaust passage.
My question -
Does the mechanic's suggestion that it's a cracked head leaking coolant into the exhaust system sound correct?
Could there be any other cause for the symptoms I have described?
Assuming it is a cracked head, is the next thing to try is a Holts Wondarweld treatment?
That was the mechanic's suggestion of what needs to be done next (he knows I can't afford to replace the head).
What do people on here think?
