Replaced hydraulic belt tensioner with mechanical - massive oil leak

[CapeCams]

Today I replaced my serpentine and ac belts and the tensioners on my 2004 330xi. There was a hydraulic tensioner that I replaced with a mechanical. This required me to bolt into a spot on the oil filter housing that previously did not have a bolt in it. I used the new bolt from the kit and near the end of tightening it down, but not yet even torquing it, I heard a noise. I finished bolting it in and replaced the belt. I started up the car and immediately a large oil leak started pooling under the car. I traced it back to the bolt area and oil appeared to be coming out of where the bolt/tensioner is connected to the housing. Any ideas on exactly what I have done and what are my remedies?
Thank you.
Cams

[MarcoZandrini]

Hmmm, I don’t remember a tensioner bolt going into the OFH. Remove the suspect bolt to see if it’s intact. I wonder if the bolt is broken. From which vendor did you buy the tensioner stuff?

[CapeCams]

Hi,
I bought it through eeuroparts. I was able to see what happened. The bolt that went into the OFH had never been used because of the hydraulic tensioner. I now see the crack in the housing right above the bolt oozing oil. I assume 14 years of heat with never having a bolt in there was the cause of the crack? I'm now looking for a used OFH. Of course, now I'm scared it will happen again with the same bolt.
Thanks for your reply.
Cams

[Liquidity]

It's because you didn't clean the threads out before you installed the bolt. This is a common occurrence on any alloy engine, especially head bolt holes. Alloy castings cannot handle the pressure of debris inside the holes when a bolt tries to squeeze past, they simply crack.

[CapeCams]

The bolt was new but the hole was dirty from never being used and I simply wiped with my finger. Hard lesson learned.
Thank you for the reply.