ticking sound in the bottom

[84cucv1ton]

working on a 87 M1031 utility truck. Has 18,000 miles on it. done a lot of sitting. Finally got it started. Sounded great. not even a minute later there is as loud ticking noise. Could hear it clear as day with a truck on high idle. shut it off right away. I cranked it a bit before starting. To get the oil circulated a little bit. I was thinking take oil pan down after work. comes off pretty easy from what I remember. If I don't see anything obvious. See how the bearings in the crank look.
Any ideas??
thanks again

 

[GM72K10]

Check for a crack in your flywheel

 

[84cucv1ton]

really? how does that work? thanks

 

[84cucv1ton]

anyone else

 

[GM72K10]

Just remove the access cover and check for a cracked flywheel.