A Short Guide to the Common Causes of a Diesel Engine Oil Leak

Oil is a significant component within any vehicle, having many different uses. One of its main purposes is to keep a vehicle’s engine lubricated and to keep all the compartments moving separately, without causing friction between one another. If there is not enough oil in the engine and friction occurs, the parts can wear quickly. Leaks can appear in the form of minor drops or large puddles, depending on the cause of the diesel engine oil leak. Below we have listed the most common signs of oil leaks, followed by the most common causes of diesel engine oil leaks, to help you identify these within your own vehicle.

Symptoms of An Oil Leak:

  • Oil stains/puddle underneath the vehicle when parked.
  • Oil levels on the dipstick gradually dropping.
  • Blue smoke coming from the engine when driving.
  • Low oil level symbol on the dashboard lit up.
  • The smell of burning oil.
diesel-engine-oil-leak

Common Causes of a Diesel Engine Oil Leak

1. The Gasket

Alongside putting the wrong oil in a diesel engine, a worn valve stem oil seal gasket is a common cause of oil leaks, allowing excess oil to enter the engine combustion chamber. This results in the excess oil being burnt, causing blue smoke to be omitted from the vehicles exhaust when driving.

2. Oil Filter

The oil filter could possibly be misaligned, loose or perhaps worn out. Depending on the make and model of your car, there may be other parts within the oil filtration system that can cause a leak too. In order to prevent this, the filter should be changed alongside the oil, at required intervals. It’s probably a good idea to check that the filter is fitted correctly whilst you do this, just to be sure.

3. Oil Filler Cap

It may sound trivial but if your filler cap is missing or isn’t fitted properly, it could cause the oil to spill out. The pressure coming from the engine causes this so, when the vehicle is running, that’s when the oil will leak out.

not-enough-oil-in-engine

4. Oil Pan

When an oil pan is damaged it can cause minor to severe leaks. Damage can occur to the oil pan when a vehicle has run over large rocks, debris or sadly even animals, leaving the oil pan on the underside dented. Once this occurs it could mean that the seal or even the oil drain plug is damaged, causing the leak.

5. Oil Drain Plug

As mentioned, the oil drain plug is at the base of the oil pan. If the oil drain plug is loose or the thread is worn out or misaligned, it could result in leaking. This cause is easy to identify – fresh oil will be around the plug and most likely dripping down the side of it too.

Remember if you are unsure of the cause of your diesel engine oil leak, or have any questions around your own vehicle’s oil, it’s always best to speak to your local mechanic to prevent any further damage happening to your vehicle. If you are worried your diesel engine is overheating, check out our previous post discussing the diesel engine overheating causes and symptoms to find out more.

If you are experiencing any diesel engine related issues, please contact us with your engine number and our team of experts will be happy to assist you.

Foxwood Diesel is a national distributor of Cummins spares and engine parts, as well as Mercedes, Volvo, Perkins, DAF and all major diesel vehicle manufacturers, with a wide range available for same day dispatch. We have a dedicated team with over 70 years of experience between us, able to undertake highly effective reconditioning and rebuilding solutions. Please contact us to see if we can help you find the right part or solution.