Review on ACDelco 9G Professional Glow Plug by Phillip Jaylon

All 4 passenger sides simultaneously. Pretty easy, sprayed penetrating oil on them the day before installing to avoid sticking problems. I didn't want to break the old ones by taking them out. Went with AC Delco to avoid problems with cheap imitations. I only want to do it once. Also take the fuel filter if you do the passenger side. Worked on gmc sierra 3500 2011. Took about 3 hours to take the fender off well, change the glow plugs and fuel filter, then replace the fender. 3 hours including a trip to the hardware store for a new batch of fasteners, the old plastic was becoming brittle. Don't pay a mechanic to do this fairly simple job.