Still trying to get to the bottom of the overheating problem on my 1.4TDI. I have described the symptoms on here before and the general consensus was that I am suffering with a head gasket failure.
Had the car in at a VW specialist for an MOT the other day and asked them to give the car a Holts Wondarweld treatment while there. The head mechanic said no to that. When I told him the symptoms he said it was an impeller failure and that I need a new water pump.
The main symptom is that I can drive the car all day long at 50mph without any problem but if I take it up to 60mph it very quickly starts to overheat. The mechanic's logic is that it is not necessary to have a fully functioning impeller until I hit the higher speed.
My concern is that his logic fails to address the secondary symptom which is that the header tank stays pressurised even when the engine is stone cold. Even after sitting for three days the tank will still spurt when I remove the cap.
My mechanical knowledge is very limited. Can someone explain to me what is causing this pressure in the header tank. Note: there is no emulsion in my oil and no steam coming from my exhaust.
My best guess is that exhaust gases are somehow getting into the coolant - despite the fact it seems no coolant is getting into any of the cylinders. Is that possible?
Note: the header tank gets over-pressurised even if I keep my speed low enough that the engine never goes above 90 degrees.
The garage wants £450 to do the water pump and cambelt. I am worried that I could lay out that money for no good reason if there is a head gasket failure. I have already had a new radiator and a new thermostat and neither of those jobs made any difference.
If it is a head gasket failure I will not be able to afford to have that rectified on top of everything else. Cosmetically the car is rough as old boots and just not worth the expense.
What's the verdict on here? Does it seem odd that the mechanic seems to think a new waterpump will cure the over-pressurised coolant problem?
Oh, one other symptom - I am losing coolant at a rate of roughly half a litre for every hundred miles driven despite there being no visible leaks.
Had the car in at a VW specialist for an MOT the other day and asked them to give the car a Holts Wondarweld treatment while there. The head mechanic said no to that. When I told him the symptoms he said it was an impeller failure and that I need a new water pump.
The main symptom is that I can drive the car all day long at 50mph without any problem but if I take it up to 60mph it very quickly starts to overheat. The mechanic's logic is that it is not necessary to have a fully functioning impeller until I hit the higher speed.
My concern is that his logic fails to address the secondary symptom which is that the header tank stays pressurised even when the engine is stone cold. Even after sitting for three days the tank will still spurt when I remove the cap.
My mechanical knowledge is very limited. Can someone explain to me what is causing this pressure in the header tank. Note: there is no emulsion in my oil and no steam coming from my exhaust.
My best guess is that exhaust gases are somehow getting into the coolant - despite the fact it seems no coolant is getting into any of the cylinders. Is that possible?
Note: the header tank gets over-pressurised even if I keep my speed low enough that the engine never goes above 90 degrees.
The garage wants £450 to do the water pump and cambelt. I am worried that I could lay out that money for no good reason if there is a head gasket failure. I have already had a new radiator and a new thermostat and neither of those jobs made any difference.
If it is a head gasket failure I will not be able to afford to have that rectified on top of everything else. Cosmetically the car is rough as old boots and just not worth the expense.
What's the verdict on here? Does it seem odd that the mechanic seems to think a new waterpump will cure the over-pressurised coolant problem?
Oh, one other symptom - I am losing coolant at a rate of roughly half a litre for every hundred miles driven despite there being no visible leaks.