Engine Bolts vs. Studs

[MFMauceri]

Engine Bolts vs. Studs

This may be a Jeep imponderable... Or not?

The oil pan is bolted on by a combination of bolts and studs. However, the Factory Service Manual gives no indication of which goes where or why? Whilst removing I made the assumption that somehow the threads must be different, or else I'd just look at the FSM for a guide to reassembly. Read: I threw them all in same box and didn't mark anything.

Any thoughts on why this is. Does it matter?

 

[macleanflood]

I don't think it matters but I thought I saw a diagram with correct bolt/stud placement. Different threads in the corners.

-Mac

 

[TJ Jim]

I’m gonna throw out that it’s part of the assembly process. Studs to align the pan then bolts to finish. Does a robot assemble or does a human?

 

[MFMauceri]

I don't think it matters but I thought I saw a diagram with correct bolt/stud placement. Different threads in the corners.

-Mac

I can't find that diagram. I always fall back on the belief that engineers design something in some way for a reason. Even if that reason turns out to be non consequential.

 

[MountaineerTom]

The 2006 service manual shows the 5/16 inch bolts in the corners. 1/4 inch everywhere else. I replaced my gasket in 2017 and remember there being some studs, but don’t remember exactly where they went. I traced the gasket on cardboard and poked the bolts and studs into the appropriate locations as I took it apart.

 

[MFMauceri]

The 2006 service manual shows the 5/16 inch bolts in the corners. 1/4 inch everywhere else. I replaced my gasket in 2017 and remember there being some studs, but don’t remember exactly where they went. I traced the gasket on cardboard and poked the bolts and studs into the appropriate locations as I took it apart.

View attachment 614979

Well, this pinpoints four out of 24 of them!

 

[jonny jeep]

The studs allow the hose guides for auto transmission cooler to be supported. If an auto isn't fitted it doesn't matter where they go.