Car leaking oil: most common causes of oil loss and what to do next

Anyone who has ever discovered a small puddle under their car knows this queasy feeling of an uncertain defect. A visible oil stain under the car usually leaves no doubt that the car is losing oil. The cause of an oil stain under the car must be found and eliminated quickly. Various, harmless or difficult to repair damages are possible. The stain under the car could be engine oil or transmission oil, hydraulic fluid from the power steering, but also cooling water or brake fluid. And that is exactly what makes conscientious troubleshooting necessary. Without a thorough examination, it cannot be clearly said where the problem of fluid loss lies and what costs the repair will cause.

Troubleshooting in the workshop

To determine the cause of the oil loss, a specialist must thoroughly check the “leaky” car. The search for the exit point is carried out systematically in the workshops. The first step is to find out what type of oil or liquid it is. This can be determined from the color and smell of the leaked liquid. Then the professional can search specifically for the respective exit point, because the oil does not always escape where it ultimately drips to the ground. The search is complex due to the many panels under the engine. Once the type of oil and the leak have been identified, the specialist checks the respective system – engine, transmission, power steering, etc. – for other weak points.

The engine loses oil

In many cases, the oil stain under the car is engine oil. Here it must be determined whether there are defects in the lines and connected units or whether the motor itself is leaking. A defective cylinder head gasket, for example, is a possible cause of oil loss. Engine oil in the fuel intake system or in certain components of the fuel and air intake (air filter and intake pipes) is also conceivable. Other causes for the loss of engine oil can be defects in the seals of the crankshaft, in the oil lines to the turbocharger, in the oil pan or in the valve covers. In principle, any contact point between two oil-carrying components can leak sooner or later.

Car loses gear oil

If, on the other hand, the car loses gear oil (between the engine and gear housing), the problem is often the defective sealing ring (simmering) on ​​the clutch side. If, on the other hand, there is a leak on the drive or the PTO shaft when there is a loss of gear oil, this indicates a leak on the oil drain plug or filler plug or on the housing seal. Sealing a gearbox in particular can be labor-intensive and therefore costly because the entire gearbox usually has to be removed and dismantled. If the hairline cracks are still visible in the gearbox, the leaky gearbox must also be replaced.

Oil loss at the power steering

Losing hydraulic power to the power steering is also not uncommon. In these cases, the oil escapes from the steering gear, the servo pump or the supply hoses and connections. A sure sign of this is – in addition to the oil puddle under the car – a low oil level or foam in the expansion tank of the steering. The servo pump would then become increasingly drier due to a lack of servo oil and would no longer be able to supply the steering with oil, which increases the steering forces. In the long term, the steering gear of the car is destroyed by too little oil.

Other causes when the car loses oil

The puddle could not be oil but also cooling water or condensed water from the heat exchanger. If there is a leak in the fuel system, it can be dangerous. If this problem is not resolved as quickly as possible, the car can catch fire in extreme cases. Brake fluid can also leak.

The options in workshops

At this point, only the most common causes and defects are listed, which can be present if the car loses oil or other liquids. A full listing would be complex because each car is designed and equipped differently. Precisely for this reason, because of the numerous types of oil and the different systems, professional troubleshooting and professional repair in the workshop is particularly important. The cost of repairing an oil loss is difficult to estimate.

Author: Nabeel K

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