I recently posted this at the end of my post at

https://www.clublexus.com/forums/ls-...der-cover.html

but that one had been read by a number of folks who probably would past on reading a part of it again. So, I deleted that end post and am re-posting it here.


The screws holding the engine under cover on are into plastic and half had been stripped out. Even though they are stripped they do not fall out as the plastic squeezes on them. This is not the way I want to drive around so I wanted to replace the screws with slightly larger ones. These screws are ¼ inch or 6.3 mm. The next available screw size is 5/16 with a 1/2 head. I thought this was too big and looked for a 7 mm screw with a 10 mm head. Well, they (7 mm screw ) do not exist here but I found a 50 mm x 7 mm Confirmat Style Euro Screw with an Allen hex drive (they also come with a Phillips head). These are furniture screws and need to be cut to 25 mm and slipped on to a nut to take up the space at the head. I fitted five of these and they firm up very nicely.

 

These 7 mm Confirmat Screws are all over ebay. The nut is just a spacer, its not use to tighten the screw. That is done with a 4 mm Allen wrench.

 

I noticed a couple of missing/loose undercover screws. Just requested my dealer to replace/tighten as necessary. No charge for the fix.

 

These are ¼ inch cover screws that are screwed into plastic which is easily stripped out and if so the screws, after seated, can continually be rotated by hand with just the 10mm socket on the end of an extension (not using a ratchet handle) . At least mine could. It seems likely the screws could work their way out as may have happened on your car.

You know the dealer is going to put in the same ¼ inch screws even in any holes that are stripped. It takes a light hand to not strip the holes out but still tighten the screws correctly. I feel much better knowing the screws I put in are not going to drop out and damage someone tire or that the under cover is not going to come lose.