Firstly it's a 59 plate Astra SRI 1.8l petrol 42k miles regularly serviced. Took it for a service today and they commented that the coolant was oily, he did say however that there was no sign of any coolant in the oil. He said if it was one of his cars he'd put a couple of dishwasher tablets in the coolant then change it and keep an eye on it, does that make any sense to anyone? Should I do it? It could be something from a past head gasket issue or the beginning of one but he couldn't say which.. Wasn't really expecting to have any issues with the car considering its low mileage and service history Bought it in November and had just been serviced and had a full health check, I've done 10,000miles since. Any recommendations/advice? Thanks! Edit: forgot to mention he said the cars running fine.