This question is about a 2014 Renault engine fitted in our family car, we've owned it since new and I've done all the maintenance to the book. We chose the petrol engine over the diesel because we knew we would use it in the city and only do less than 5000 miles per year with it.
It has 13,000 miles currently and has had 3 oil changes (one per year). The manufacturer says it can go 12,000 miles or 1 year before needing an oil change. All the service parts have been bought from the dealership so they are genuine oils and filters. The coolant has never been changed.
The car drives around 8 miles each day in the city, barely exceeding 25 - 30mph during this trip, it's stored in a (non-heated) garage over-night. It doesn't get used much at the weekend either.
Today, I checked the oil and found there was a mayonnaise or creamy substance at the tip of the dipstick. About 2 or 3mm of the stuff. The rest of the oil is a healthy golden colour and the level is half-way between the middle and max line. The oil cap looked normal and from what I could see of the timing chain through the filler hole, everything looked normal.
The only time I've seen this kind of thing has been consistent with head gasket failure, but it has been much more widespread, i.e. on the filler cap.
What (if anything) should I do?
It's only recently had its oil changed, so that won't be due for another 11 months according to the handbook. Also, the next service is a major one, it calls for the coolant to be replaced too. The coolant in the expansion tank is green, but it isn't as clear as it was when it was new. Is this a red flag?