MY OCTAVIA TDI 130 seems to be losing water, not sure where can't see any external signs. cars still runs well, so is it worth trying to change hg myself but can't see any guides online. Anyway to test it besides getting a garage to check. no signs on mayo on dipstick or cap or in coolant.

 

mentioned online might be oil cooler?

Edited 6 May, 20179 yr by billybob699

Check before starting the engine in the morning whether there's any pressure in the expansion tank. 

Try the bottom left hand corner of the radiator as my old radiator done this. 

Also,  this could be the water pump and you won't see any sign as it's all covered up behind the timing belt cover.