Fan center bolt backed out, I'm betting it's not as simple as just bolting it back in. Options

[Mikey914]

I'm letting the boy work on this as it's his car and he should be able to turn a wrench.

The car overheated and he didn't know why. So we figured it was an obstructed oil cooler, or flaps may have been closed. After poking around and checking he found the fan has come loose. From what I can see with a mirror the center bolt has backed out and is MIA. Along with missing center washer.

What should I be looking at here?

[Cap'n Krusty]

In general, replacement can be really simple or major-league difficult. The big issue is whether or not the crank and/or fan hub are damaged. There are 5 main components involved. The crankshaft, the hub, the Woodruff key, the special washer, and the bolt. All need to be correct and in good condition. To find out whether or not the components are OK, you'll need to get in there with good light and a mirror. Check the condition of the snout on the crank, and especially the condition of the keyway. If the snout is smooth and the taper undamaged, and the keyway is clean and the edges sharp, you've gotten past the difficult (and expensive) part. Examine the tapered surface on the inside of the hub. If it's good, then you clean everything up, replace the seal and the o-ring on the crank, and install the key, the hub, the correct thick washer, and the special locking bolt. Install the spacer and the fan using three bolts of the proper length, hardness, and configuration. Some fans use hex head bolts, some use Allen head bolts. The torque is 15-18 ft/lbs. The taper takes the load, not the bolt.

Note! If there are ANY damaged mating surfaces, you'll need to replace the affected components! A taper fit by design MUST be clean, smooth, and tight! I probably have a hub somewhere, and I KNOW Bruce Stone has some, 'cause he got at least one from me.

Good luck, The Cap'n