Stripped threads when installing oil filter housing
 

I was replacing the oil filter housing gasket, vanos line and alternator today on my M54 when I accidentally stripped the threads of the engine side when installing one of the oil filter housing bolts and am now unable to properly tighten the bolt. The bolt itself seemed to be okay. It was the one in the left side when looking from the drivers’s side towards the engine, the lowest one. I believe there was also a dovel pin in that hole. In other words, the bolt is not in the area of the actual gasket.

I quit for today and will continue tomorrow and my question is now that is the only option here to make a new thread with Helicoil or similar or do you think it would be stupid to let it be or would it just 100 % lead to a oil leak? What I’m wondering is that how critical the lowest bolt can be when the gasket seal is considered or is it just for mounting the filter housing to the engine? And if I could get away with just using Loctite on the bolt to make sure it doenst fall off.

Any tips are welcome and use the torque wrench. :D

Oh, and I read somewhere that the holes are deeper and the threads in the engine block extend deeper than the bolts, in which case could a longer bolt also work? Not sure if that is accurate info though.

Not the end of the world, but you do need to fix it…

The threads do go deeper than the orig bolt, but not by too much.. order a couple longer bolts ( you likely won’t find the right thread and length in any hardware store) and be prepared to shorten them to exactly the size you need with a dremel.

If that fails, put a helicoil in…when drilling for the helicoil, put the other bolts in their holes to help align the angle of your drill. The angle there is a little strange.

I have been through this. As a result, I tighten those bolts gently with one hand using a small 1/4 inch drive ratchet. Tight is right, any more and it’s broken…

Helicoil or timesert in your future.

On smaller screws I've just tapped the next size up. I do not know if there's enough material to go that route butt I bet there is. I could use my reference book to establish the proper torque to match the same tension.

If it was my car I think I would try that since the next step using helicoil will be to drill a similar hole used for tapping.

https://uploads.tapatalk-cdn.com/202...6e34f87c20.jpg

7, 8, 9?

It seems that I might just be able to find a suitable bolt from the store, I’ll go and look tomorrow. Otherwise Helicoil, Time-sert or similar it is then.

@Andrewwynn, I believe it’s number 7 from the picture.

If you want to make the best use of what threads are left you might be better off using(making) a stud and loctiting (or JB weld) that in instead of a longer bolt.

That's a stellar idea! Go 80s! I change my answer! I would absolutely do that. JB will hold way stronger than what's needed and lots less work. Prep and I think you need to use the high heat so it won't get weak.

I posted similar issues and solutions in OFH job in bimmerfest E39 5-series forum.

Some just ppl just leave it alone and it is fine since it is lowest bolt.

Just fire up the engine, drive for a few weeks to see if you have any oil leak.

PS: sometimes during removal, the bolt (steel) bonded with the threads (Aluminum) over the years, so the Aluminum threads come out with the bolt(s).

Thanks for the tips guys, I put the car back together and what I ended up doing was replacing the bolt with a longer one. It was Sunday so the options were limited and I needed the car in couple of days. Also bought the thread fixing kit just in case. The stock bolt was 50 mm long and I was able to find bolts with similar thread from the local store with lengths of 60 mm and 70 mm. The 70 mm one was too long but the 60 mm fit perfectly and torqued into the spec. Also applied some Loctite to the threads, time will tell if any leaks will occur.

@cn90 The aluminium threads definitely came out with the bolt, although I assume it was due to me overtorquing the bolt.

By the way, anyone else have had issues with logging in to the forum lately? For several days I was just facing error saying something about wrong username or password and to try again in 15 minutes?