Rain, road drains and reading a leak in winter
Diagnosing a leak at home in a Norbury winter is close to impossible. Rain washes the evidence off the road within hours, the underside of the car is permanently wet anyway, and Norbury Brook rising quickly after heavy rain is a reminder of how much water the local drainage moves. Drivers quite often come to us convinced they have a serious leak when the dark wet film under the car is mostly road spray, and just as often with a real leak they have dismissed for the same reason.
Telling them apart takes two minutes on a ramp and a clean rag. Engine oil is amber to black, slippery and does not evaporate, and it attracts road dust into a gritty film that spreads wider the older the leak is. Water sits in beads and dries. What matters far more than the quantity is where it is going. Oil onto a cambelt, a clutch, an exhaust, an alternator or a rubber suspension bush has to be dealt with whatever the rate of loss, because of what it destroys.
After that it is method rather than opinion. The area is steam cleaned so no historic oil remains, measured dye goes into the sump, you carry on with your normal driving along the A23, Northborough Road and the roads around Norwood Grove for a few days, then an ultraviolet lamp shows the exact escape point. We check crankcase pressure in the same visit and give you written findings naming the source, with a price for that repair and a straight view of anything that can be left.
The way down is the A23 to the Pond, west as far as the Lombard roundabout, then out over Mitcham Common and south on the A237 to Hackbridge. If the level has dropped far enough that you are topping up to get anywhere, leave the car and ask about collection instead. We will give you an honest estimate of when we can reach you, and the repair itself carries our 3-month workmanship warranty.