Drain plug question - what actually is leaking, threads or mating suface washer to pan?

TiGeo

TiGeo

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I get weeping from the drain plug on my VW MK7 Golf Sportwagen. I have an aftermarket aluminum oil pan that uses an aluminum magnetic drain plug and single use aluminum crush washers. The recommended torque is ~20 ft lbs. Is the weep/leak from:

1) The threads (so you would say use HD teflon tape on them).

2) The mating surface where the crush washer should deform (I think?) to seal the drain plug against the pan.

Do I need to just tighten up (litterally!) and get that crush washer more deformed/tighten it more?

Don't forget folks, this post is set up on the forum using the "question" format so you can vote for the best answer with the arrows off to the right of folks' responses!
 
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TiGeo said:
I get weeping from the drain plug on my VW MK7 Golf Sportwagen. I have an aftermarket aluminum oil pan that uses an aluminum magnetic drain plug and single use aluminum crush washers. The recommended torque is ~20 ft lbs. Is the weep/leak from:

1) The threads (so you would say use HD teflon tape on them).

2) The mating surface where the crush washer should deform (I think?) to seal the drain plug against the pan.

Do I need to just tighten up (litterally!) and get that crush washer more deformed/tighten it more?

Don't forget folks, this post is set up on the forum using the "question" format so you can vote for the best answer with the arrows off to the right of folks' responses!
Click to expand...

can't you find a washer that's softer than the pan and bolt? Nylon or something? the whole point is that the washer deforms and mates with the pan and bolt but that won't work if the washer is as hard or harder than them. so copper or aluminum on steel parts work. or a washer with a rubber insert of course
 
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Jetronic said:
can't you find a washer that's softer than the pan and bolt? Nylon or something? the whole point is that the washer deforms and mates with the pan and bolt but that won't work if the washer is as hard or harder than them. so copper or aluminum on steel parts work. or a washer with a rubber insert of course
Click to expand...
Yes they was the plan...and what I just did per the post above...
 
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TiGeo said:
No thanks dude. It's good to get under your car once in a while and look around. It's like at most 2x a year. I'll keep doing it old school.
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Nothing wrong with old school. However, I use an extractor and STILL get under the cars several times a year to look around. It's very peaceful and zen-like under there. Except at my age and back condition, getting up is the trick 😁.
 
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TiGeo said:
I didn't realize there were 2 different sides here...it's all the same...
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Ditch the crush washer entirely and replace it with a Stat-o-seal of the appropriate hole size for the threads. You might need to upgrade to a drain plug that has an unthreaded portion under the head.

https://www.mcmaster.com/products/stat-o-seal-washers/

Parker offers these seals in a huge range of sizes in both nitrile and FKM elastomers. You want the FKM. They don't leak and can often be reused many times without the seal separating from the washer carrier. The key is to not overtorque them. Just tighten it until the carrier washer just starts to compress.

As a bonus, you'll have a lot less risk of thread stripping from overtorque trying to make a metal-on-metal seal (SMH) for oil.

The FKM elastomer works from -20F to 400F.
 
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Use these for HYUNDAI Accent and KIA Soul .

IMG_9248.webp
 
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Update. Still getting a drip, even with the new LN steel mag drain plug and a new copper crush washer. I drained the oil...again...and had a really good look at the mating surface as clearly that's the issue and did find a small ding/spot (hole). I noted the crush washer had a raised spot where it tried to fill it in. This has to be the source. Sanded the mating surface a bit and used a new Amazon copper crush washer AND put a small amount of high-temp thread sealer on the washer. Re-used the HPL I had in (only 5K miles/2 track days/1 autoX on it). Hoping this helps fill in that tiny spot and stops this madness!
 
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Copper work-hardens and isn’t as good a choice for sealing washer vs soft aluminum.

The elastomer stat-o-seal is your easy button here. Heck, they will seal a regular bolt of correct threads—it doesn’t even need to be a drain plug bolt.
 
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TiGeo said:
Update. Still getting a drip, even with the new LN steel mag drain plug and a new copper crush washer. I drained the oil...again...and had a really good look at the mating surface as clearly that's the issue and did find a small ding/spot (hole). I noted the crush washer had a raised spot where it tried to fill it in. This has to be the source. Sanded the mating surface a bit and used a new Amazon copper crush washer AND put a small amount of high-temp thread sealer on the washer. Re-used the HPL I had in (only 5K miles/2 track days/1 autoX on it). Hoping this helps fill in that tiny spot and stops this madness!
Click to expand...

Good luck .
 
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