Engine oil leak: how to spot it

An engine oil leak can be slight at first then get worse. Spotting the signs and source early limits risks (engine wear, smoke, fire) and costs. Here is how to spot it and where to look.

Warning signs

Stains under the vehicle (drops or puddle of black or brown oil) after parking. Oil level dropping between checks (check on level ground, cold engine). Burning oil smell in the cabin or under the bonnet (oil on the exhaust). Smoke under the bonnet or on start-up (oil on the exhaust manifold). Oil warning light if pressure drops significantly.

Where to look

Common leaks: sump gasket (under the engine), drain plug or oil filter not tight, head gasket (often oil + coolant), turbo (hoses or cartridge), oil pump, cam cover. Cleaning the engine then driving a short distance and checking where oil appears helps locate the leak.

What to do

Do not drive with a large leak or low oil level: risk of engine failure. Topping up in an emergency can get you to a garage, but the leak must be repaired. A loose drain plug or filter is a quick fix; a head gasket or faulty turbo costs much more.

Order of magnitude for costs

Sump gasket: €150–400. Loose plug or filter: often fixed in minutes. Head gasket: €800–2,000 and more. Turbo repair: variable (€500–2,500). My Auto Check-up helps you prepare your visit by describing symptoms for an initial estimate.