My car (Superb Mk1 1.9tdi 130 Edition 100, 55 plate with ~120k miles on the clock – full service history!) has been losing coolant steadily for a long time (probably since just after I became the owner – around April/May I guess). The garage I have been using (VAGtech in Milton Keynes) have been very helpful in assisting me trace the source of this issue. We thought at first that it was the radiator as it had a hole in the rear, but I wasn’t that convinced due to the amounts involved. If driven carefully on a commute it would lose an average of 1 litre a week, but when on the motorway it would easily consume 5 litres plus on a 200 mile trip. We replaced the rad anyway. I tried using radweld and other proprietary preparations to solve the issue – all to no avail.

The engine was pressure tested and no leaks could be found either on a cold engine or a hot one. Clearly a frustrating problem.

Fortunately I have a Warranty Direct policy (I took it out just after I got the car) so was able to take the plunge, knowing that the head is covered. When the head was removed it was found that the head gasket had corroded apart at the compression ring to water jacket area. This meant that normal pootling about wouldn’t pressurise the water system too much, but high loads would. It also meant that there was no ‘mayonnaise’ type discharge in the oil filler cap as the gasket hadn’t failed between the oil and water systems.

So – if your 1.9TDI 130PD system is losing coolant but not showing any major signs of head gasket failure (difficult to start, oil in coolant/coolant in oil, misfiring, clouds of white smoke from the exhaust) then it may be down to this kind of failure. I guessed it was likely to be a water jacket/compression chamber leak as there were no outward signs….

So far diagnosis has been £199, the repair is estimated at £1200. My warranty costs me £29 a month through Warranty Direct. No brainer really

Mine is losing coolant slowly, but I hope it's not that as I can't afford £1200!!!

Is it really £1200 to change a head gasket these days .... or am I misreading something??

Takes me back to the days when my brother used to change the head gasket on his Hillman Imp almost every Saturday morning without fail .... until he bit the bullet and had the head "Wills ringed".

Also recall numerous head gaskets on minis just to replace the damned bypass hose that had split, and doing my old Hillman Hunter's head gasket by the side of the road once when I figured it wasn't worth the risk of driving it home ( new fangled aluminium heads and acid .... mutter , mutter)

Why does it cost so much .... are dentists moonlighting?

Sorry. I ought to explain a bit more now. The garage had estimated for cambelt change too. The warranty company wouldn't Go for that so the repair cost (including skim and pressure test of the head) will be more like £850. All labour is paid for, my contribution is £120 and I get a Vauxhall Insignia for the duration of the repair paid for too :-). I'll be using warranty direct again!

Eurgh. Vauxhall Insignia!

You'll be happy to get the Superb back after that!