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Discussion Starter #1 (Edited)
My 1996 RMW had to be smogged so took it in and asked for it to be put on the hoist so I could tighten the oil pan bolt. There had been leaks the last few weeks and I could see drips hanging on the bolt.

The bolt would not tighten, it felt like stripped threads. Paid for an oil change to check the condition of the threads (hoping it would be the bolt) but it was the oilpan. Next discovery was that the filter could not be removed, it required multigrips and lots of force to release it.

The last oil change was 800 miles ago, it was done while buying tires. The manager of the tire store looked at the files, looked at the filter, and told me he would order an oilpan from Buick and call when he had it. His shop would do the work.

If replacing the oilpan requires sensors, fuel line, transmission line, etc to be uninstalled to make room to remove it then the likelihood of problems after pan replacement seems high.

A Timesert repair might be a lower risk solution. If done carefully using grease on the drilling and tapping to catch the debris ought to prevent any in the pan. A couple of quarts before the bolt is installed to 'flush' plus a magnet bolt to gather any stray filings would also help.

This wagon has been troublefree. The cosmetics are still good and it only has 109K, so it has years of service life left.

I want to keep things that way so am looking for advice. The tire shop is stepping up to the responsibility, and I seek opinions on what you guys think would be the lowest risk solution.

1996 RMW LT1

Thanks
 

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OK. So, you had a tireshop gorilla do your oil change. No big woop, - the world is full of them.

Helps aisle at the parts houses sell repair bolts all day long for exactly this purpose and reason. I've used them myself NUMEROUS times. I'm flabbergasted the shop did not itself press you to permit them to use a less costly remedy as that.

The downside for you is there's HIGH probability of "going from bad to worse" with all manner of potential NEW leaks from replacing a pan even under the best circumstances using a good mechanic. I strongly recommend against a tire shop doing this job, no matter how well-meaning the owner is.

I hope I answered your question.
 

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No way,would I allow these folks to do the work.
 

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The proper way to fix the stripped thread is a helicoil. They are available at any parts store. The kit includes a drill, tap, and the coil itself. You may need a 1/8 inch carbide end mill and a dremel to clean up the end of the coil.

You need to know the thread you have now (or don't have now) and get the repair coil for that thread. You can catch the chips with a magnet (a "magnet on a stick", available at the parts store, will work). Put the magnet in a plastic bag so that you can get the chips off of it. Just go through the current hole in the pan with the helicoil. You do not have to open the pan up to do the job. You may have to remove the clamping rail, but you can put the bolts, on both sides of the one you are repairing, back in with washers under them until you reinstall the clamping rail. You could use a part called a mending plate, available at a hardware store, to give more support to the pan around the stripped hole. If you miss a couple of chips, they probably will not even get into the pan, because you have not broken the seal of the gasket. The hole in the pan may be fractionally larger, but the rail will hold the gasket tight against the edge of the block and gasket flange on the pan.
 

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A Timesert repair might be a lower risk solution.
While the best solution would be a new oil pan carefully installed by someone who is competent, I think , here, the Timesert is a better choice over the Helicoil due the shallow nut used inside the pan .
I think you will end up with more usable threads and a more solid result.
 

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Available at just about every auto parts store is a 1st 2nd and 3rd oversize oil drain plug for repairing this issue. If you would rather bring it back to the original size then a time-sert is the answer but I don't know of any auto parts stores that sell them so you'd have to order it from Time-sert which is located in Torrance Ca. their phone number is 800-372-4477.
 

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I watched the Time-sert vid. Seems an improvement over heli-coil for many applications.

It sure seems like we're over-complicating this though. I always favor the most expedient least invasive (in this case proven effective and cheapest) fixes, then only upon continued failure progressing from there.

http://www.autozone.com/autozone/accessories/Dorman-Oversize-oil-drain-plug/_/N-25r9?itemIdentifier=150004_0_0_

Not pretty, but I've even used these with success until I could do the self-tapping bolt above

http://www.shawplugs.com/
 

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Discussion Starter #9
Status Update

Spoke to the tire store guy, and this is why he wants to go with a replacement pan.

a) timesert kit to thread capture insert into current hole and reduce bolt size to 7/16 is #0765 but..., it requires that the threads be in a crossed state and not having been chased to re-use the old bolt - it cold rolls the old thread for the timesert inset. Since my old bolt screwed in easily and cannot be torqued down, it has been chased.

b) the timesert kit 0122A requires that there be enough material to screw the oversize insert into place. Timesert says at least 1/8 of material around the current hole, and he thinks the RMW pan falls into the category of marginal at best, and likely not enough.

c) The Dorman-Oversize-oil-drain-plug which comes as 1st/2nd/3rd oversize plugs may work, but tend to require stepping up to the next size after repeated oil changes.

He feels the only option for a successful repair is pan replacement.

The 0122a timesert is the most appealing solution, but requires there be enough material. If any of you have a pan and can check the material thickness at the drain hole, or have actually installed a replacement timesert I'd really like to hear from you.

Thanks guys.
 

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I may have misunderstood your first post and was thinking it was one of the many pan bolts holding it to the block. But it sounds like you are talking about the drain plug bolt in the side of the pan. Is this the one?

If so, I have a spare stock LT1 pan in storage. I believe there is a pretty thick and wide plate there where the drain plug threads in. If this is the case, then I could get some close up pics of the pan (inside/out) and post them up for you. Let me know.....
 

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Discussion Starter #11
I may have misunderstood your first post
My bad, I never used the word 'drain' in my post.

If you can check the thickness it would be much appreciated, and if it does have a plate then the timesert will be feasible.

Thanks
 

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jaipea,


From what I saw on the Time-sert vid it looked like you need 5/8" or more for the "last 3 threads" to expand and bite. Even if not quite that much depth is needed, it seems certainly more than the meat on the bolt area of any production oil pan I've ever seen -- except on maybe a tractor.

On your point C. about the Dorman re-treading oversize repair bolt, I vaguely recall something about not continuing to use the repair bolt after you've made the initial installation, but to replace it with a normal bolt of the the correct pitch for the new size. Either the instructions or just common sense (I've lost both since the last time I used one of those repair bolts cwm2) is/was to keep the hardened repair bolt from continuing to gouge into the threads and causing you to have to go back and 'repair the repair' with an even larger bolt as you remarked. Of course if that's the case, then I'm wondering why no-one (unless I missed it) has suggested just trying a regular re-tap to a slightly larger thread.

Finally, found this for more ideas/options along the same vein:
http://www.hotrodders.com/forum/repairing-stripped-oilpan-drain-plug-hole-201438.html
 

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Discussion Starter #14 (Edited)
If your car is a 96, unless I am mistaken , it should have a metric drain plug
It is unclear according to the chart at http://www.cgenterprises.com/buick1980.htm

1994-96 ROADMASTER V8 350 5.7 Plug, 1/2-20
1996 ROADMASTER V8 350 5.7 Plug, M12 x 1.75

Both were used in 1996, and that's a complication factor.

My issue is the same no matter what the bolt size, go with a larger bolt or use a timesert.

Maybe this is where the problem started ?
Could be, if the guy who did the oil change picked up a different thread oil pan bolt to the one that he took out. I don't know how it happened, but I do want the best possible outcome since the tire shop is taking responsibility.


...it looked like you need 5/8" or more for the "last 3 threads" to expand and bite.
Was the video on spark plug threads? The oilpan insert is 0.4" and 5/8 is 0.625". A 1/2" nut is 8mm and 0.4 is 10mm, so 0.4 would be the right depth for a brazed nut on the inside of the pan.

I vaguely recall something about not continuing to use the repair bolt after you've made the initial installation, but to replace it with a normal bolt of the the correct pitch for the new size.
That makes sense to me, but none of the literature mentions what size thread the single/double/triple cuts. I assumed that they were unusual sizes with -20 pitch threads and unlikely to be available as standard bolts.

I'm wondering why no-one (unless I missed it) has suggested just trying a regular re-tap to a slightly larger thread.
That was my first search, but it keeps coming back to 'how much material is around the oilpan hole'. If the oilpan has a 1/2" nut brazed to the pan, then unless the nut is oversized the next size up of 9/16" leaves very little of the nut left. If there is a 17/32" bolt, I've never seen one.

Finally, found this for more ideas/options along the same vein...
That is the www.mactools.com/shoponline/product/tabid/120/p-319651-oil-pan-plug-rethreading-kit.aspx which says it
- Works on soft steel and aluminum oil pans with 1/2", 12 MM and 14 MM threads and
- Contains: 5 Magnetic Plug and Gaskets
but..., there is no hint as to the size of the re-thread so am left unclear on whether there is enough material left. If it works on 14mm threads then the new thread size is larger than that.

I am staying with the 1/2-20 size for discussion purposes as that is the worst case scenario. If my pan has a 12mm thread, a 1/2" re-thread should succeed. The drill size for 1/2-20 is 29/64 which is 11.5mm and any remaining 12mm thread after drilling ought to cold-roll into the 1/2-20 thread.
 

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I got u some pics but can't post up til tomorrow...no PC tonight. But from what I can see, there is not a lot of material on the inside of the pan where the threads are. It's a fairly thin layer of threaded steel that's about 1/4" into the pan and is sandwiched to the pan with a flat piece of thicker steel that's tack welded to the inside of pan.

If they can't successfully repair the threads then a pan replacement may be needed. Even if they fix it, I would be concerned with future oil changes and would they still replace it later if/there is a problem.

Something to consider if you want to avoid pan removall/replacement is something more permanent. If the threads are "decent enough" for a one time thread in, this may work....

Get a steel plug that fits the threads and also has a threaded hole in the center and a flat face. You then thread this into the pan with some sealant, tack weld it to the pan and then use another smaller bolt with a washer or O-ring that threads into the inside of the plug. This smaller bolt is what's removed for future oil changes.

If all else fails then a new pan may be best. You have to decide if trust them to do it cause it is a big job. Not complicated but you do risk disturbing other parts and seals. Again something to consider with a pan replacement. Hopefully a retread of some sort works. Just consider where you may be months later with future oil changes if the fixed threads fail.
 

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Hopefully thes pics help you/them find a simple fix for the drain plug. Good Luck!!





 

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Discussion Starter #17
With the assistance of 'wobbler' extensions I was able to check the bolt on my oilpan, it has a 15mm head.

...what I can see, there is not a lot of material on the inside of the pan where the threads are.
Great photos, and the inside is not at all like what I expected, there is even less material for threads than on the nut I expected to see.

My enthusiasm to re-thread as a 1/2" has been diminished by your photos, there isn't much meat in that triangle.

Get a steel plug that fits the threads and also has a threaded hole in the center and a flat face...
So far, have found no bushings in metric, there are choices at 1/2".

The timesert 0765 is a 1/2" repair bushing with a 7/16" drain plug. The 64 dollar question is whether there is enough meat in the 12mm triangle to hold the repair bushing. If not, then maybe seat the insert and tack weld it in place.

After this learning exercise I'm beginning to think the tire store guy has been down this road before and pan replacement is the proper choice.

Thanks for the photos, they are excellent.
 

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---- Now You Just Hush

I don't want to be an arse just jd weld it lol ..wow what a mission
Sure, the recommendations of that crackpot way back in Post #2 offer the most practical and proven fix. But remember from your management classes, there is no such thing as a bad idea during the brainstorming phase.

And while there's no way in hayol I'd let a tire shop unhook my motor and mess with my oil pan for a measly stripped oil bolt, I've nonetheless learned about some products for future reference that can be useful in other applications.
 

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Discussion Starter #19
The drama continues...

No fix implemented yet, but have decided on a course of action.

- There are no 12mm solutions like the 1/2" bushing to take a 7/16" bolt.
- Tapping the 12mm drain hole to take a 1/2" plug is still a possibility, but the lack of meat on the inside of the pan is a worry.
- A call to Henkel confirmed that Loctite 263 is tolerant of oil, and should cure properly if the threads are cleaned before insertion.
- Ordered an F107S Oil Drain Valve from Qwik Valve

The fumoto valve should be a permanent non-leaking fix when red loctited in place.

There should never be a reason to remove the fumoto, and if there is then it's back to replacing the oil pan so will not be in worse predicament than the present.
 

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That's the way to go. I completely forgot about those Fumoto valves and had one on my Camaro many years back. They work really well and you just lift up on the valve and slide it to the side to open. As long as you can get it to permanently mount to the pan, that should be a good solution and much easier than a pan swap. :)
 
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