Hello all,

Just replaced the turbo on my 850, and found the block to exhaust manifold bolts to be barely finger tight. Most of the studs came out with the nuts. When I reassembled I used a torque wrench to ensure the spec was met.

After reassembling the system, the car was sooooo quiet. It made my heart sing. Then, after less than a week of driving the engine is starting to get loud again. I'm pissed off to think I'm going to have to remove the turbo again, but W/E, lesson learned.

My question is, what should I put on these studs to stop them from backing out when I rebuild this thing again? Is there a good reason NOT to put loctite permanent on the studs when I thread them into the block?

 

I put loctite on the last set of exhaust studs that I did earlier this week.

 

What type of loctite did you use? I've done a bit of reading on a BMW forum about this, and it seems that the red medium strength has the highest heat tolerance.

 

I used red loctite on it because that's what I had in my toolbox. If you want to make damn sure they don't come out use the green one haha

 

On some alum heads I found regular high temp silicone holds the studs from vibrating out. Lock-tite, not something I would use. The lock-tite turns brittle after getting heated, eventually turning to dust, the silicone never turns brittle.


If you dont like the results of using silicone, its easier to clean off then lock-tite.

 

Gene, I think you may be onto something there. I tried thread sealant, as thats what the repair manual suggested, but clearly it hasn't worked all that hot.

I have the same sentiment about loctite, I just don't think its going to hold up to the heat.

It's going to be a couple months before I can pull the turbo again, but I'll report back with my findings when I do.