thanks to eveyone who sugested a faulty EGR cooler was the reason for large water loss and poor heaters you were all spot on.but now i have had the new cooler fitted i cant get the car out of limp mode,it seams to come out of limp mode it its self every now and then but always goes back into it.i can clear the codes which are p0403 but not get it out of limp mode.it is a 1.9 tdi 2007/8 superb.any sugestions would be appreciated.i am thinking a faulty EGR valve due to the cooler being faulty but just guessing.

I had a limp home as I was buying my Superb 1, two years ago. It was the (I believe) DPF regenerator had glogged up due to the previous owner doing just a couple of miles a day for a period of time. The only solution they had was to get the thing re-set by the garage.

Sorry if I am right.

Edited 17 March, 201214 yr by Danny 57

Can you run a basic setting on the EGR valve via VCDS? Does the EGR cooler have an exhaust gas bypass? If so it could be stuck/faulty.