i have a 1998 astra 1.6 8v club, i keep noticing that there is white "Mayonaise" type stuff under the filler cap each time i check it, which normally is the signs of a headgasket failing. im slightly confused though as i dont seem to be loosing any coolant and there is no residue on the dipstick. Also my temp dont seem to be going over 80 while im driving and got the blowers on but bumps up to around 90 when im stationary and no heaters is this normal? as its never been like that on any other cars i have owned. Any help would be greatly appreciated thanks.