If you're having trouble removing a *spin-on* filter, here are some reasons why and how to fix them:
* Too tight: This is the most common cause. You need a good quality oil filter wrench that grips the filter firmly. A strap wrench is often better than a cap wrench as it can grip a damaged or rusty filter. Try using penetrating oil (like PB Blaster or Liquid Wrench) on the filter's gasket area and let it soak for at least 15-20 minutes, even overnight if necessary. Then, apply firm but steady pressure to loosen the filter; avoid jerking or twisting violently, as you could damage the filter or the engine block. A filter wrench that you can attach to a breaker bar can give you significant leverage.
* Filter is rusted or corroded: If the filter is severely rusted or damaged, the penetrating oil may help, but you may need to use more aggressive methods. Consider using a strong pair of channel-lock pliers or vice grips *as a last resort* – be incredibly careful not to damage the engine block. If you're concerned, take it to a mechanic.
* Incorrect wrench: Ensure you're using the right type and size of oil filter wrench for your filter.
* Filter is stuck to the mounting surface: Penetrating oil can help here as well. Once loosened, you may still need a bit of force to separate it.
If you still suspect it might be a bolt-on filter (though highly unlikely), you'd be looking for a small bolt or cap in the center of the filter housing. This is *extremely rare* on a 1981 305. However, if you cannot find the usual spin-on filter, take some pictures of the area and post them online to get help identifying the setup.
Important Safety Note: Always wear safety glasses when working under a car and take care to avoid skin contact with used motor oil. Dispose of the used oil and filter responsibly.
