Where did this dowel pin come from?

[KMinAF]

18 months ago I replaced the head gasket and the engine has run perfectly until last week when an unusual whining noise was heard for about 2 days followed by a significant oil leak at the front of the engine. I pulled the top T belt cover and found a groove cut in the belt along with shredded belt fibers mixed with oil all over the inside of the cover. After removing the front cover I found this dowel pin! The oil leak I believe was caused by all the belt fibers getting caught between the sprocket and seal. I have no idea where the pin came from and how it has gone 18 months without any problem! I am guessing it happened when I did the head gasket as that was the only time the cover has been off. Yes, the locating pin on the left side for the front cover is in place. What do you think, aliens, vindictive ex wife, jealous neighbor?

 

[toyotanos]

My first guess is that its the pivot for the timing belt tensioner.
My next guess is that its the cam sprocket pin (too small, I think)
Lastly I think it might be an alignment pin for the lower front timing cover.

Good luck with the repairs!

 

[KMinAF]

AWESOME! Since the engine is apart waiting for new oil seals from Toyota, I went and checked the pivot pin as suggested and sure enough it was missing. I will make sure to use lock tight and stake it in place this time. Is this a common failure? I would never have thought to check that the pivot pin was securely in place I guarantee from now on I will be checking on all the cars that I do T belts on. Thanks for the help.

 

[toyotanos]

Sweet! No need to stake it, just a dab of blue locktite and tap it into the rear timing cover! It's more common than most people think