I have a Vectra 2.0 DTI 1998, it runs very smoothly, it is almost
138,000 miles. yesterday I went to KwikFit to change oil and filter and the worker there told me there is some oil leak coming from the engine block somewhere. I am not sure where it comes from as it seems from the front and the back of a rectangle box that I could I see down the car. any idea what possible sources of this leak? does such a leak require immediate action (i.e. send to a garage?)