HI, I'm doing head gasket job on my friends 2000 S40. There is odd shaped bolts that secure sprocket to VVT unit on exhaust cam. I've never saw bolts with head like this and curious what kind of socket required to install them??? This is not Torx for sure, the Torx Plus looks a little different as well. I went to local NAPA and Oreilly and nobody saw these as well. I pulled one with some good pliers to get a picture. Maybe someone knows???

 

How many "dents" are in it?

It looks like some variety of security head.

 

Possibly a Pentalobe.

 

Unfortunately this in not Iphone 4G))))

 

Looks like torx plus, as it has 6 sides. The pentalobe has 5 sides. Check with the Fastenall Company, they have locations around the US. Google them and send them the photo. They will know what it is asap. When I rebuilt the head on my 2000 S40 4 years ago, I got my head bolts from them. Much cheaper (80% less) than Volvo head bolts, and they are stronger (Grade 9 bolts). Fastenall has saved me alot of money over the years in auto bolts, ect, and they have EVERYTHING. Check them out.

 

Pentalobes have been around for the better part of 50 years.

 

It could be a slightly rounded off Torx Plus.