Mayo on oil cap and water problems

[Vinjy]

Hi guys.

I have a slight problem with my MK1 1.4MPi.

I replaced my water pump 2 months ago and then I noticed that I lose water the last 2 weeks (I go from max to half inch below min line on expansion tank every 100 miles).

First thing I checked was the water pump but no leaks from gasket or pipe. In doing this I decided to take that plastic engine cover off for unrelated reasons... Took the oil cap off aaaand mayo, lots of it. It was not there when I changed the pump.

What I did:

Checked dipstick and it was fine - the oil was thick enough. Took rocker cover off and the mayo has thinly coated the top of it but the rockers are cvered with oil coat as normal with only the area around te cap covered in mayo. There is no oil in expansion tank. I put the cover back on etc and ran the engine on tick over and got it got enough to make sure no air in water system (some bubbles came out then when the fan switched on I topped up to max mark and put the cover back on and turned the engine off).

As it was cooling it started making a tssss sound from the expansion tank overflow bit but no steam coming out and the water level dropped to about half inch under min mark in 5mins. No engine and surrounds were bone dry.

Can anyone make any sense of this?

The car done 40k in 5 years that I had it. Only replaced fluids and filters and brakes.. and the pump lol.

[Vinjy]

I appreciate any and all help and suggestion and hope you can help, I want my car to live two more years :P

[haribo(felicia)]

sounds like the headgasket has gone take it to a local garage and get a sniffer test done .