Hi, Just wondered if people could give me any ideas as to what to check as I am loosing coolant far to regularly. I have been filling the header tank up to the max mark and after some journeys it has been completley empty. I have checked all of the pipes and cannot see any obvious leak but the coolant does appear to be coming from the header tank area ( If there has been any leak I find 3 small puddles on the floor from that side of the engine bay but have struggled to chase this to a particular area). I have changed the thermostatic fan switch and the header tank bottle cap. I have also completley drained the system down and changed the coolant for G12++ at 50/50 ratio.

Any ideas?

Is the coolant clean and the engine oil mormal looking?

yes sorry forgot to mention- I have recently changed the oil- it was clean though- no mayo. Coolant is also clean- I changed it for the 1st time in 2 years whilst I was changing the fan switch and the old coolant was remarkably clean.

Please help!!

There's no sign of any white crystals or orangy staining anywhere?

How about mayonaisse, or the oil level rising?

I have not seen any staining anywhere- i had a cambelt change about 2k ago and my mechanic told me that the pump was also clean.

I have just changed the oil and there was no evidence of mayo or oil level raising.

Well, that seems to point us at one of:-

blowing coolant out of the expansion bottle.

a split in the header tank.

HGF blowing coolant into the exhaust. In this case it goes the other way too, and it's fairly simple to test for exhaust gas in the coolant. I'm not convinced this is likely, but at least you can eliminate it if you do the test.

and my mechanic told me that the pump was also clean.

.

or failure to use a new O ring when refitting the water pump?