Heater issue

[KW@611018]

Thanks for the replies,
I do have VCDS but the temp gauge display within the car remains a steady 90 degrees C. We drove the car to Berriedale, North of Scotland approx 5 hour drive with no problems. Recently driven through Edinburgh with no over heating problems temp steady at 90. I did think of an open thermostat.
As I previously posted I think I will back flush the matrix and possibly test the thermostat.
Any thoughts on this course of action.
Kenny

[Crasher]

Ignore the dash gauge, it reads 90 at 77 and still reads 90 at 117

[KW@611018]

Okay,
How do you measure coolant temp with VCDS ?

Kenny

[Crasher]

In advanced measuring blocks it is available a number of times in various controllers but in address 17 instruments you can see what the dash is receiving against the displayed reading, the disparity will make you laugh but I don’t recommend going for the 117 degree test!

[KW@611018]

Thanks will have a look.

Kenny

[tdiblacky]

In my golf I had an issue with the hot air lasting for a couple mins when initially switched on and then it would change to cold air. Both my hoses at the bulk head were getting warm. I flushed the matrix a couple times and no dirt or very little came out. I fitted a new matrix as a last resort and all was back to normal. I cut open the old matrix to have a gander and it was lined with a weird goldy coloured stuff, don't know what it was.

[Crasher]

Sound like lime scale from using tap water. Since the Golf 2, VAG heater matrix's have been burst proof top flow designs that you can't flush. Since 2017, VAG have said distilled water only.

[KW@611018]

Crasher, Thank you have answered my question re flushing the matrix, stating the matrix is top flow type NOT flow through type.

It would suggest the problem may lie with the thermostat stuck in the open position.