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As I and others have said, the drain plug has most likely been overtightened by some knuckle dragging neanderthals over the years, hence the threads in the oil pan have been stressed and stretched to the point they're no longer fluid tight.
The torque is specified for a reason, that being to stop people overtightening the drain plug and causing exactly what you're experiencing. In the good ole days of steel plugs and steel oil pans, you could get away with an extra nipping up of the plug, unfortunately aluminium doesn't afford you that luxury.
I understand that the plug has been over tightened but what does that have to do with the seal. They're parallel threads, like BSP. The seal comes from the crush washer. I don't see where that disturbs the seal except perhaps it distorts the flat on the pan somehow. Also, I don't think putting loctite on the threads is a good idea. It's not a tapered fit with the sealant to full the gaps like NPT. The flat, the crush washer, and the flange should make the seal.
Last edited by Prairiedawg; 03-03-2024 at 10:53 PM.
The thread is damaged (most likely stretched) due to being over-tightened.
It no longer allows the sealing washer to do it's job, either because it's not pulling up square and/or because the threads are elongated and incapable of stopping fluid running down the threads themselves and past the washer. See "2. Leaks" here :
Forget about thread form. Read the description of the product I linked to carefully. Then buy a bottle of it and use it, it'll stop the leak, it's what it's designed to do. Or use this : https://www.autozone.com/sealants-gl...4oz/162305_0_0
Putting sealant on the threads of the oil drain plug is a bad idea. The problem is people will tend to put too much and the extra sealant could dislodge and get caught in the oil pick up tube. Seen it many times when people put too much on the perimeter of the sump plate. If you want a better seal, then put some sealant on the crush washer.
Putting sealant on the threads of the oil drain plug is a bad idea. The problem is people will tend to put too much and the extra sealant could dislodge and get caught in the oil pick up tube. Seen it many times when people put too much on the perimeter of the sump plate. If you want a better seal, then put some sealant on the crush washer.
No, putting thread sealant on isn’t a bad idea, but as you’ve rightly said, putting too much thread sealant on, is a bad idea. As is not using a torque wrench to tighten the drain plug to the correct torque.
Tightening that plug to the Porsche listed spec of something like 38 ft lbs, even with a torque wrench, is way too tight for a steel plug into an aluminum pan, 19 ft lbs is what I've used for a combined 80k miles on my 2 997s and I'm still using the same plug (new washer every time) and have never had a leak.
Using the too high spec is probably what has stretched the aluminum sump plate threads and created the leak in the first place.
Tightening that plug to the Porsche listed spec of something like 38 ft lbs, even with a torque wrench, is way too tight for a steel plug into an aluminum pan, 19 ft lbs is what I've used for a combined 80k miles on my 2 997s and I'm still using the same plug (new washer every time) and have never had a leak.
Using the too high spec is probably what has stretched the aluminum sump plate threads and created the leak in the first place.
The torque setting for the 996.2 drain plug is 19 ft lbs
Ordered those listed above and they DO NOT fit over the plug even though they are a M18 size. The rubber interferes and won't slip over. The Grainger washer fits easily. The ones above are noted as self centering and have extra rubber material which does not work for this application.
Just following up a bit. My car has been in storage since last November. Took it out and brought it home last week. Today I swapped out the leaking crush washer and plug for a LN magnetic one with the Grainger Dowty bonded washer. PN 55DV22
I tightened it to 19 ft/lb and it seems to be working. The torque spec for the washer is 30 ft/lb but I'll start at 19. You can always go tighter. So far it seems to be holding without a drip. I'll let it sit for a few days and see how it goes but so far they seem to work.
I have ordered from Rosepassion maybe a dozen times already, they still continue to be one of the cheapest options most of the times. However 1 time I ran into an issue.
I was ordering a part, and assumed that everything they have is OEM, however they sent me a generic Door Sill piece. I had to return it back to France, and was out $30 shipping + restocking fee since I returned it past 30 days.
Lesson learned, just remember to email them if you suspect something may not be OEM (like my door sill piece, there are hundreds of chinese knock offs out there).
03-03-2024 | 12:12 PM
