Author Topic: M42 Lower Oil Pan bolts (Read 4503 times)

batsbats · « **on:** April 24, 2008, 07:26:36 AM »

Hi guys! I'm reposting my bf.c post, hopefully it will get more attention here.

I think I'm experiencing what bmwman91 had, with the upper oil pan's threads being stripped. As of now, 7 out of the 16 bolts will not completely thread. They go in all the way. I believe these are the original bolts and pan.

Anyway as per most M42 owners, I decided to check the oil pan for loose bolts. I applied some liquid wrench to the area (I don't think this is the cause of my problem below), and removed the stuck pan with a dead blow hammer. Some of them were really on there. I don't know if it was over torquered or they were simply stuck.

Good news: None found in the lower oil pan. All visible 6 upper oil pan bolts there. I took them out and added loctite red for safe measure.

Bad news: Putting it all back together, with an OEM oil pan gasket + little gasket sealant to hold it in place, about half the bolts aren't threading all the way. I can hand torque them all, but half of them feel like they are stripped. They sort of 'reset' and they lose the little torque they had. I do realize these only need 89 inch/lbs. I pulled out the ones that refused to be torqued, and they all had some kind of previous silver stuff, that I ignored when I first pulled them. This should be the aluminum off the upper pan's threads :mad:.

Is helicoil my answer? Having to do 7 of them seems like a pita. How can I prevent this from happening again if I were to remove my oil pan? I seriously did not put much pressure when initially putting them in. I'm going on a limb and will say the bolts that I applied the liquid wrench directly into, aren't stripping.

EDIT: If I go for helicoils, what size should I get?

Wise Old Dog · « **Reply #1 on:** April 24, 2008, 07:49:03 AM »

Time Serts would be my first choice (not cheap), followed by helicoils.
And the easiest fix would be to pull the pan, clean the sealing surface, and use silicone gasket maker to seal it.

Cobra Jet · « **Reply #2 on:** April 24, 2008, 08:06:05 AM »

Is there enough "meat" to use larger diameter bolts (of course you would have to re-tap the holes to the proper bolt size/thread)?

batsbats · « **Reply #3 on:** April 24, 2008, 08:35:16 AM »

Quote from: Cobra Jet;47770

Is there enough "meat" to use larger diameter bolts (of course you would have to re-tap the holes to the proper bolt size/thread)?

yes. I actually threaded a random longer bolt, about 25% longer than the original one, and it either, threaded above where the original one couldn't reach, or it's a mm wider. I was able to tq it down, and its difference in size, pushed it through, visible through the other side (on top).

batsbats · « **Reply #4 on:** April 26, 2008, 08:31:08 AM »

Ok, only 1 bolt is completely stripped. I'll be checking the oil levels on a weekly basis. Otherwise, the 5 (6 total pwned) longer bolts I bought held up fine with some loctite blue.

kowalski · « **Reply #5 on:** April 26, 2008, 09:48:32 AM »

i've heli-coiled about 9 of the pan bolts. it works great.

batsbats · « **Reply #6 on:** April 26, 2008, 12:17:38 PM »

Quote from: kowalski;47935

i've heli-coiled about 9 of the pan bolts. it works great.

I thought I had it bad, wow. What size helicoils did you use? m8x1.25?

kowalski · « **Reply #7 on:** April 27, 2008, 05:07:40 PM »

Quote from: batsbats;47945

I thought I had it bad, wow. What size helicoils did you use? m8x1.25?

yeah. wasn't bad, and they hold up great. I've also had to heli-coil all but 2 of the valve cover bolts. whoever worked on this motor before me really didn't like the idea of using anti-seize...