losing water 1997 mk5 2.5di

[chasnjess]

Hi I have to keep topping up my coolant . Had a new timing belt and water pump fitted 1500 miles ago I lost about 1 litre of water on a round trip of about 1000mls. Have checked oil and there is no loss at all no sludge no oil in water bottle I cannot see any visible leaks. The heater works ok no overheating on temp gauge and I dont notice any loss of power. Has anybody any ideas ,not sure but I dont think its the head How do I check a possible air lock and any other causes and any other checks I can do..................Bruce

[npjrogers]

I am having a similar problem.. also after changing timing belt.. did you ever find a cause?

[twin wheel camper]

6 year old thread bud and the guy hasn’t logged on here in 3 years
Very unlikely to get a reply from him but I’m sure others will give you ideas ASAP if your patient.

[davyjcb]

You mightn't see water but a coolant leak will offer leave a tell tale white residue around the site of a leak,small leaks can be hard to locate as they only weep and when the engine is running the cooling system is under pressure plus it's hot so the coolant evaporates off showing no sign.
You could try a pressure tester and leave it on the system to see if it pushes any coolant out when the engine is cold so eliminating the evaporation
If you can borrow a tester look on your cap and you will see the working pressure printed that the system works at IE how much before the system vents do not exceed this when you pump the tester up there's no need and you could cause other problems in doing so

[Jim Archer]

9 times out of 10 it's the waterpump - even new ones.

Other common places to check are the heater hose that runs round the head, and the 3 way fitting on the back of the timing case that the bottom and heater return hoses connect to.

Finally, heater cores are known to start leaking, and being hot all the time will evaporate off - as Davy says - meaning you don't usually see liquid until it's really leaking.

Jim