Spotted a little oil patch under your car? Is the top of the engine oily, or can you smell burning after a drive? Chances are you've got an oil leak, possibly a valve cover oil leak. It's pretty common on cars that have a few years and miles behind them. Most of the time, it doesn't mean you need to pull over immediately. But here's the thing! Don't keep putting it off. Today's little oil patch could turn into tomorrow's expensive problem.
Where does a valve cover oil leak or other engine oil leak usually come from?
- The valve cover gasket — over time, the rubber hardens and can no longer keep the oil where it belongs.
- The oil sump seal — especially when the sump is sealed with silicone sealant.
- The oil filter and oil cooler seals.
- The crankshaft oil seals — either at the front of the engine or on the gearbox side.
- The vacuum pump on diesel engines.
Why does an engine start leaking oil?
Gaskets and seals don't last forever. Heat, age and constant contact with oil eventually take their toll. But there's something else that often gets overlooked — the crankcase ventilation system. When it isn't working properly, pressure builds up inside the engine and starts pushing oil past the seals. You replace the gasket, everything looks lovely and dry, and then, a while later, it's leaking again. That's the problem right there. If you don't fix what's actually causing the leak, your new repair won't last long either.
How do we pinpoint the source of an oil leak?
- First, we clean the engine so old oil doesn't send us looking in the wrong place.
- We check the crankcase ventilation system to make sure it's doing its job properly.
- After a short drive, we inspect the engine and look for where fresh oil first appears.
- If we still can't see the source clearly, we add a special dye to the oil and check it with a UV lamp.
If oil is dripping onto the exhaust or the turbo, please don't ignore it. It can start smoking and, in the worst case, even catch fire. That's when the risk becomes serious.
How do we fix an oil leak?
If the leak is coming from the valve cover gasket, we fit a new genuine gasket. We thoroughly clean the surfaces where it sits, then tighten the bolts with a torque wrench, following the exact specified torque and tightening sequence. Because you can't just throw a new gasket on and tighten everything as hard as you can. Overtighten the cover and it could leak again. Leave the bolts too loose and you'll get the same result. And if the crankcase ventilation system is causing the problem, we fix that too. Otherwise, before long, you'll be looking at the same oily engine all over again.
A tip from Kris Mladenov: Check your engine oil level once every two weeks. If you've got a leak, the level can start dropping long before you notice a big oil patch under the car.
Noticed an oil patch under your car, or is the engine oily around the valve cover? Don't guess where it's coming from. Bring your car to Das Auto Service. We'll find out exactly where the oil is escaping and why, so we can fix the cause rather than just clean up the mess.
The solution in our shop
Genuine LongLife III FE 0W-30 engine oil, 5L
Genuine engine oil that meets the exact manufacturer-specified standard, if you need to top up or change the oil after the leak has been repaired.
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- Complete engine rebuilds
- Diagnostics at Das Auto Service
- 2.0 TFSI burning oil and whistling: a crankcase ventilation problem
- 2.0 TDI: the vacuum pump that's leaking oil
- Inside the TDI cylinder head: camshafts and hydraulic tappets
Frequently asked questions
Is a small oil leak dangerous?
If the oil isn't dripping onto hot parts, you're not necessarily in immediate danger. But don't leave it. Get the leak fixed before it gets worse or causes damage elsewhere.
Why is it leaking again after replacing the gasket?
The first things we need to check are the crankcase ventilation system and how the cover was tightened. If we haven't fixed the real cause, even a brand-new gasket won't keep the oil in for long.
How do we find exactly where the oil is leaking from?
We clean the engine, take the car for a short drive and look for where fresh oil starts appearing. If the source isn't obvious, we add a special dye to the oil and check it with a UV lamp.