If you think your cat has consumed any of the motor oil that’s on its fur, go to the vet. It’s much better to be safe than sorry. If your cat is vomiting, has diarrhea, isn’t breathing normally, or has an irregular heartbeat, get to the vet’s office as quickly as possible.  If you see your cat licking itself before you have a chance to remove the motor oil, go to the vet. If your vet’s office isn’t open, go to an emergency vet clinic. Do not attempt to make your cat vomit before you visit the vet! Some products can actually permanently damage your cat’s esophagus. Your cat will be clipped and bathed at the vet’s office, just as it would have been at home. Depending on your cat’s condition, your vet will either do this right away or take care of urgent medical issues first. The vet may also provide you will topical antibiotics that you’ll need to put on your cat’s skin to prevent infection. The vet will order a complete blood profile, a urine test, and an electrolyte panel. Each of these tests will help your vet determine which of your cat’s organs are being affected by the motor oil. Since motor oil can sometimes cause pneumonia in cats, your vet may also order an X-ray to see if your cat has built-up fluid in its lungs. If your cat vomited at home, take a sample of the vomit for your vet to test. You can collect it with a resealable plastic bag. Be sure to wash your hands after you’ve gotten the sample. This may help your vet treat your cat more quickly. The charcoal will help absorb the motor oil and halt any damage it’s causing in your cat’s system. If your cat ate the motor oil recently, your vet may also flush your cat’s stomach. If your cat is struggling to breathe, oxygen therapy may help stabilize it while the motor oil is removed from its system. This treatment can only be given at your vet’s office, so your cat will need to stay there for as long as the oxygen therapy is necessary. Sometimes IV fluids will also be given to support the cat's internal organs. If your vet allowed you to take your cat home, you’re probably in the clear. However, it’s a good idea to monitor them closely for the next several days to make sure they’re healing from their ordeal. If you see them panting, coughing, or if they have an increased heart rate, take them back to the vet right away.

Summary:
Go to the vet right away if your cat appears to be poisoned. Expect the vet to remove the motor oil. Wait for the results of diagnostic tests and scans. Allow your vet to give your cat activated charcoal. Give more severely affected cats oxygen therapy. Continue to observe your cat once you return home.