Ivs got this yellow thick oil gunk stuff in my oil filler gap???? what it it....i told a local garage about it he said change the oil it could be a bit of water in the engine car runs fine should i be worried.:confused:

can anyone help?

That's a classic symptom for head gasket failure. The white gunk is caused when water mixes with the oil. As the mechanic said, it can build up if you do lots of short journeys - if this is the case than a good long drive should rectify it. If it's the head gasket then the coolant will probably be going down too?

that can also happen if the car is used for lots of short trips where the engine never gets warm.

Yup. If it doesnt vanish after a long drive may worth be getting a coolant test done which will test the system out and perhaps a compression test done in each cylinder.

Never actually done a 1.8T head gasket on its own before.

Noticed I had some mayo on my oil filler cap last year after moving closer to work (4 miles commute now instead of 34!). I just change the oil every 5k now instead of 10k and do the occasional long run.

Agreed - if you do mostly short runs this is a classic symptom of the engine not ever getting properly warmed up.

Quick first checks for head gasket failure would be to look in the coolant bottle for any sign of oil, and to look for signs of water on the dipstick. I'm not saying that you can't get HGF without these, but either of them is highly diagnostic of HGF.

thanks guys.