How to Determine if Diesel Has Entered the Engine Oil

[CamillaDella]

Methods to determine if diesel has entered the engine oil: 1. During routine oil maintenance, pull out the dipstick. If you notice a sudden increase in oil level and detect a diesel smell, it indicates diesel has mixed into the oil; 2. Drop the oil from the dipstick onto an oil test paper or tissue. If the oil spreads quickly and widely with a lighter outer ring color, it suggests diesel contamination. Engine oil provides cleaning, lubrication, rust prevention, noise reduction, shock absorption, sealing, and cooling for the engine, directly affecting its lifespan. Diesel in the oil reduces viscosity, impairs lubrication, accelerates engine component wear, and may cause cylinder scoring or bearing seizure, ultimately affecting vehicle performance.

[VanSamuel]

I've encountered this issue many times before. To check if diesel has mixed into the engine oil, you can start with a few steps. Open the hood and pull out the engine's dipstick to observe the color first. Normally, engine oil is brown or black. If diesel has mixed in, the oil will appear more turbid or even shiny, sometimes with foam. Next, take a sniff – diesel has a distinct pungent odor that's easily noticeable up close. Thinning of the oil is a key indicator; normal engine oil is quite viscous, but when mixed with diesel, it becomes thin like water, feeling slippery and lacking viscosity when touched. Also, watch for vehicle symptoms: the engine might shake violently or lack power because diesel seeping in contaminates the lubrication system when you accelerate. It's best to use specialized test strips to quickly determine the contamination level – it doesn't take much time.

[OGarrett]

My old car had a similar issue last year, and diesel mixing into the engine oil is really troublesome. After starting, the car shook like an earthquake, and I noticed the oil level on the dipstick was inexplicably higher with an odd color—shiny and slightly foamy. When I got closer, the pungent smell of diesel hit me. Then, I touched the oil and felt it was thin and lacked viscosity. Normally, oil droplets would cling to the walls and not slide down so quickly, but this time they flowed rapidly. While driving, the engine sounded like it was fighting, rattling loudly. I suggest addressing it early before the engine gets damaged.

[VonAnna]

When I was a novice, I would panic when my car had issues, but learning to check the oil is actually quite simple. If diesel gets into the engine oil, pulling out the dipstick will show the oil level significantly higher than normal because the diesel causes the oil to expand. The color will appear unusually bright or have a slight white foam. It also smells different, with a distinct diesel odor compared to regular engine oil. Additionally, you might notice the engine feels less responsive, and the acceleration is sluggish when you press the gas pedal. If you're unsure, it's best to have a mechanic take a look.