Your going to put a 3D printed PLA part under the hood? Your going to have a melted pile of goo within a few minutes of driving. Even ABS can't handle under hood temps. There are a few exotic plastics that can handle 400 degrees plus temps and be fine. You get over 150 degrees and PLA starts to get soft and warp. You put PLA in a black sealed car on a hot Arizona summer day and the interior can hit 180 degrees inside the vehicle. Goodbye PLA parts. PLA will start to shrink around 130 degrees(can shrink up to 5%), warp at around 150 degrees, and start to melt/severely deform right around 170-180 degrees. I know this from personal experience when I first started 3D printing a few years ago. I started making cup holders in PLA. I had to replace almost every one I sold with an ABS version. I only print in ABS now for interior car part applications. PLA is only good for prototyping and not functional use. PLA also breaks down and becomes very brittle very quickly when out in the open. It will definitely not last the test of time. ABS will go 20 plus years before it starts having structural issues. Develop your skills with ABS and you should be good. If you need some pointers shoot me a PM and I can help you out.