I put the wrong oil in my car — what now?
One journey on a near-miss grade is rarely fatal. Here is how to judge how urgent it is, and what to do next.
First, work out how wrong it is
There is a large difference between a 5W-30 where 5W-20 was specified, and a full-SAPS A3/B4 oil in a car with a particulate filter. The first is a viscosity mismatch that mildly affects the timing system. The second actively shortens the life of an expensive component. Check what the bottle carries against the specification for your engine before deciding anything.
If the grade is close and the approval is right
Drive gently and change it at your convenience, ideally within a few hundred miles. The additive package is correct, the oil film is simply thicker or thinner than intended, and a modern engine tolerates that for a short period.
If the approval is wrong
Change it sooner rather than later, and change the filter with it. Running a high-ash oil through a DPF or an oil without a wet-belt approval past a wet belt is accumulating damage you cannot see and cannot undo.
If it is not engine oil at all
Gearbox oil, ATF or hydraulic fluid in the engine means do not start it. The additive chemistry is wrong for engine internals and the viscosity may be far outside what the pump can handle. Have the sump drained before the engine is run again.
A registration lookup returns the grade, approval code, capacity and interval for your exact engine — free, and without a sign-up.
Check my oil