Oil drain bolt leak

[HKF]

So attempted to change the oil myself for the first time. Set torque wrench to 33 ft-lb with new crush washer. For some reason, the bolt would not tighten and just keeps turning. I removed it and bolt was stripped. Went to get a new bolt/washer and this time, it tightened to 33 ft-lb. But the plug now has a slow leak (a drop every few minutes). I took a chance and tighted the bolt to 34.5 ft-lb to see if it may help, but the leak is still there.

Any suggestions? I'm guessing tightening it more may not help and may strip the bolt again. The car was not leaking before, and I'm not sure where I messed up. I can live with the slow leak until next oil change but will need to find a solution.

Thank you!

 

[Big McLargeHuge]

Sorry that someone before you probably buggered it up and didn't fix it right. With a new bolt and washer torqued right, the only reason it would still leak is that the threads on the oil pan are damaged. Did you take a look at the pan threads in addition to the ones on the bolt? Are you sure it's leaking from that spot and not from somewhere above it? Are the new bolt and washer OEM parts?

If yes to the above then you'll probably have to take off the oil pan, which involves taking off part of the exhaust as well, so hopefully you still have the OEM headers. Once that's done you can repair the drain bolt threads or install a new pan which is ~$280. You can repair the threads with the pan installed but you'll probably leave metal shavings inside the oil unless you flush it out somehow. If your oil pan is leaking in other places, maybe now would be a good time to address that too.

 

[furinax]

Another solution would be to buy a fumoto valve. I have one but haven't installed it. If you could seal the threads (assuming they are the cause of the leak) somehow and install the valve, you would never have to screw/unscrew anything from that pan any more. Oil changes are much easier and you wouldn't have to fiddle with the pan. It appears the part number is F-106 according to this thread, which is similar to your situation: http://www.nsxprime.com/forum/showthread.php/107360-Oil-Drain-Bolt-Problem

Of course, this is assuming that is the source of the oil leak. Confirm it first. I am sure Autozone experts could tell you what to buy as an oil sealant for the plug.

 

[Big McLargeHuge]

I agree, I have a Fumoto on my daily and like it a lot. You can get the slightly more expensive one that can rotate to point away from the ground to get more clearance and a clip to keep the valve lever from opening accidentally, which is near impossible anyways. You could either seal up the threads somehow to prevent the same leak problem, and/or get a slightly larger valve to "re-tap" the threads but a bit risky if it still leaks.

 

[HKF]

Are you sure it's leaking from that spot and not from somewhere above it? Are the new bolt and washer OEM parts?

Yes, its definitely leaking from the drain bolt. And yes, OEM bolt/washer from dealer.

Another solution would be to buy a fumoto valve. I have one but haven't installed it. If you could seal the threads (assuming they are the cause of the leak) somehow and install the valve, you would never have to screw/unscrew anything from that pan any more. Oil changes are much easier and you wouldn't have to fiddle with the pan. It appears the part number is F-106 according to this thread, which is similar to your situation: http://www.nsxprime.com/forum/showthread.php/107360-Oil-Drain-Bolt-Problem

Of course, this is assuming that is the source of the oil leak. Confirm it first. I am sure Autozone experts could tell you what to buy as an oil sealant for the plug.

I would definitely consider putting in the Fumoto valve, but I assume it will too leak unless I get a new pan (or fix the thread somehow)? Or am I missing something....

Thank you for all the suggestions.

 

[Big McLargeHuge]

The valve might leak if installed in the same way the OEM bolt would be since the pan threads seem to be damaged, but you'd have the luxury of not having to ever remove it, so you might be able to use an oil-resistant thread sealant to semi-permanently install it and prevent further leakage. That or using one size up of valve as sort of a self-tapping insert.

If it were my car, I'd go for the valve & sealant option first to avoid removing the pan if at all possible. Drain again, clean up the threads on the pan carefully to get all the oil off, apply sealant & wait to dry, fill oil, and take a peek underneath for the first few trips after to check for further leaks. The biggest "if" would be the long-term ability of the sealant to prevent oil leakage past the valve threads especially if the sealant was contaminated by oil before drying, but with a bit of research and prep I'm sure there's a good product out there that will last until the next time you need to take the pan off (i.e. for gasket replacement/baffle install/etc.)

 

[goldNSX]

Teflon tape is your friend.

 

[warrenw]

The 33ft-lb spec is too high in my opinion.
When ever I have tried to torque to that spec I never get there. Tried a couple of different wrenches. It just seems too much for that bolt pan setup.
I normally go with a feel using the torque wrench. Always stop before the 33 click
Crush washer always seems rightly crushed the next oil change.
BTW, people reusing crush washers is part of the problem.
If you are going to reuse the crush washer, file it smooth first and take the ridge off it. Don’t reuse too often.


Sent from my iPhone using Tapatalk

 

[Old Guy]

Check the mating surface where the crush washer comes up against the pan. I am thinking that there might be a nick or other damage in that surface which is the source of your leak. If you can torque the drain plug to 34 ft-lb, the seal is created by the crush washer deforming between the flange on the bolt head and the mating surface on the pan. As long as the threads are in good enough shape to allow sufficient bolt torque to deform the washer it should seal if the mating surfaces are in good shape.

If you do have a nick in the pan you could try fixing it with a file; but, the in-situ pan is not exactly convenient to work on. I think that you run the significant risk of creating a non square to the bolt flange mating surface which will then definitely leak more than one drip every few minutes. I would be inclined to go with @ goldNSX 's suggestion of wrapping the bolt in a few layers of Teflon (actually PTFE because Teflon is a brand name) tape. Get the yellow tape which is meant for gas fittings because it is thicker than the white tape. The other option would be to try and find an O ring that matches the diameter of the drain plug.

 

[goldNSX]

BTW, people reusing crush washers is part of the problem.
If you are going to reuse the crush washer, file it smooth first and take the ridge off it. Don’t reuse too often.

My recommendation is to NOT reuse a crush washer in general. The flexing of it is an important part for its sealing property. Don't ask me how I know.

 

[acortez]

Oil leak fix

Hello. I stripped my pan a while ago using an aluminum magnetic bolt. I installed an Eco-Plug. Its a magnetic plug that comes with a rubber gasket. You can use it with stripped threads. Ive had it for 3 years. 0 leaks and it removes in 1 second. Hope this helps.

 

[DocL]

My recommendation is to NOT reuse a crush washer in general. The flexing of it is an important part for its sealing property. Don't ask me how I know.

It's been a while since I've done an oil change myself, but why skimp on a $0.50 washer and risk a leak. This never made sense to me.

 

[goldNSX]

It's been a while since I've done an oil change myself, but why skimp on a $0.50 washer and risk a leak. This never made sense to me.

True.
The story back then went like this:
- changed the oil
- filled in too much oil
- opened the screw again to drain excessive oil
- retorqued it
- small leak
- torqued it further
- next oil change: found the threads of the oil pan somewhat 'fishy' (more resistance) but not destroyed
- lesson learned

 

[DocL]

True.
The story back then went like this:
- changed the oil
- filled in too much oil
- opened the screw again to drain excessive oil
- retorqued it
- small leak
- torqued it further
- next oil change: found the threads of the oil pan somewhat 'fishy' (more resistance) but not destroyed
- lesson learned

Gotcha. I can see that happening.

 

[Kaz-kzukNA1]

Probably the bolt was over torqued in the past and the mating thread was already damaged.
Now that the bolt kept spinning, at that point, the thread was destroyed.

If you managed to tighten the new bolt to the spec without any repair carried out to the mating thread, then most likely, it was cross-threaded, screwed in not square or the new bolt had different thread pitch.
The original bolt is M14 x 1.5.

This is how the mating thread is created on the sump.

You are not alone and happened with other NSX owners.
Since you asked the question here, probably best letting someone carry out the task.


The proven options.

1. Use M15 x 1.5 drain repair kit (original bolt is M14).
There is enough meat on the flange to go 1mm wider.
You can find lots of M15 drain repair kit on amazon, ebay, etc.
Before attempting the repair, inspect the washer included in the kit.
Depending on the kit, the internal/external diameter of the washer included may feel like not suitable for the purpose.
If that is the case and doing oil change regularly by yourself, just get good extra M15 sealing washer.

2. Use M14 x 1.25 spark plug repair kit.
Unlike the Recoil/Helicoil using the stainless, etc wire coiled in loop, this type of kit comes with very short height one piece metal insert, just like the Timesert.
Find the kit that comes with the short insert.
You need new drain bolt as you can't use the original one that has 1.5 pitch.
Get M14 x 1.25 drain bolt.

3. Replace the oil pan/sump.
The obvious choice if removing the sump in the future.
To do it properly, you will need removing the front exh downpipe or header to create 100% oil free mating surface.

There are other 'quick fix' methods but never used by myself so can't comment on them.


Kaz

 

[HKF]

Thank you for all the suggestions.

The Eco Plug looks very interesting. Almost feel I can always try this first, and if it doesnt fix it, move to the repair kit.

@Kaz, I recall when I re-installed the bolt the second time, i could only hand tighten half way and then had to use the wrench. So it may be true it is cross-threaded. Do I need to remove the oil pan to use the bolt repair kit, in order to remove traces of metal shaving created during the repair?