To whom it may concern,Either the manufacturing tolerances on these plugs are WAY off, or I received one that was overlooked during the QA process. I sell hundreds of Dorman products at work each year and I have never seen such poorly cut threads on any of their products, and I generally stand by their quality, however...The plug only goes half a turn and resists, and I know better than to force it. At first, I thought that I mistakenly ordered the wrong pitch like an M18-1.25 or M18-1.75, because it was behaving as such, but no. It is supposed to be an M18-1.5 plug going into an M18-1.5 hole, and this plug IS supposed to be M18-1.5.I realized that the main issue is the first guiding thread, which you can see in the photos I've attached. It appears bent inward and disfigured, and these defects continue all the way up. Before you say that perhaps I tried to force it and cross-threaded it in the process (it sure looks similar), I always guide bolts/plugs in by hand and confirm that they will thread in *all the way* by hand before I even touch my tools. This puppy went in maybe a half-turn TOPS before meeting resistance when threading it in by hand and I then backed it out immediately. I visually checked the threads on the hole and they are pristine, I also used a thread gauge to check the old plug and it is an exact fit, not "sort of" a match like this Dorman plug is. I can easily thread the old (and mangled) plug *all the way* in by hand with zero resistance.This product, however, is *sort of* an M18-1.5 but the spacing is really the only thing that lines up. It does not even come close to being in spec when it comes to the way these threads were cut. It may have worked if these imperfections were consistent or uniform, but they are haphazard and random. Look at the photos. The start of the thread is the worst by far and that's why it met resistance, but there are imperfections all the way up it. It looks like someone randomly ground the crest/teeth of the threads down to where the "tooth-like" profile looks more like a square, maybe the thread-cutting machine was having an off day or was in dire need of a fresh carbide insert. There is also a small chance that someone DID cross-thread it, perfectly re-box it, and return it. But that seems like a lot of work for a $5 part.These things happen in manufacturing, but this one made it into a sealed box, through the mail, and into my freezing cold hands while trying to work on my girlfriend's car. I had to special order a 1'' bolt-biter (HUGE) just to get the old one off and now I can't put the new one in because it was so badly manufactured that it would only *MAYBE* screw into SUPER sloppy threads. Unfortunately, my girlfriend's fill hole is nowhere near sloppy enough to insert this plug. I wish I was kidding, but I'm not.It isn't worth it to me to go through the return process for a $5 part, and a new, more accurate plug would take too long to arrive so I will be forced to either grind the old one down to a different head size, or weld a bolt head onto the old plug assuming it's steel, which is so much more work than just having a usable product in the first place, so I am writing this review to hopefully save someone the time and money that I lost by purchasing this product (DOR 65220).TLDR / My Advice: This plug may work for sloppy holes on older models, or you may get lucky with what they send you and it'll go in nice and easy first try. However, if you know the tolerances will be tight, save yourself the time, money, and most of all, the hassle, and pick up a high-quality plug elsewhere.Sincerely (hanging by a thread),Caleb Carroll