Rubber o-ring for oil sump plug

Rubber o-ring for oil sump plug

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Discussion

jay44

Original Poster:

119 posts

115 months

Wednesday 14th August 2019
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Hi,

After doing an oil change, I overtightened the bolt and ruined the thread. Instead of tapping out s larger bolt and using a helicoil, I was wondering if using a rubber o-ring would make a proper seal opposed to a copper crush washer. I know you can't use PTFE on the thread because of how it frays on tightening/under heat, but you could wrap PTFE inside and outside of the actual rubber o-ring to create a tighter seal (like wrapping a bandage round someone's arm). Would that also be okay or would the hot oil also degrade the PTFE in that setup?

Benbay001

5,795 posts

157 months

Wednesday 14th August 2019
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How will you compress the o ring into the sump if the thread is stripped?

Evercross

5,956 posts

64 months

Wednesday 14th August 2019
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Benbay001 said:
How will you compress the o ring into the sump if the thread is stripped?
This.

Face up to the error and fix it properly.

Decky_Q

1,511 posts

177 months

Wednesday 14th August 2019
quotequote all
Is it an aluminium sump? Threads are pretty easy stripped in these, but on the plus side they are also quite easy to tap or fit a coil into as the metal is so soft.

O ring won't work as crankcase is under pressure and if there's an easy outlet at the sump plug then the pressure will just push the oil out past your makeshift seal.

jay44

Original Poster:

119 posts

115 months

Wednesday 14th August 2019
quotequote all
Decky_Q said:
Is it an aluminium sump? Threads are pretty easy stripped in these, but on the plus side they are also quite easy to tap or fit a coil into as the metal is so soft.

O ring won't work as crankcase is under pressure and if there's an easy outlet at the sump plug then the pressure will just push the oil out past your makeshift seal.
The thread isn't compromised, I just tightened it past the maximum (I don't know the correct way to say this), so the threads are there, there are just too many now which means there's not s tight seal.

Very interesting about the pressure. Didn't even consider that, thank you. I'm happy to buy the helicoil kit, I'm fine to get stuck in but nervous with new things with cars. I'm not sure about the material.. it's s BMW e82 (1 series coupe)


Matt_E_Mulsion

1,693 posts

65 months

Wednesday 14th August 2019
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Don't bodge it, fix it properly. If it fails and falls out whilst in motion you could potentially end up with a knackered engine all down to not fixing the thread of the sump plug properly in the first place.

Rewe

1,016 posts

92 months

Wednesday 14th August 2019
quotequote all
I’m pretty sure you can buy tapered sump plugs for just this situation.

I’ve never used one, I have no idea if they work and I would be too scared to try!

RizzoTheRat

25,162 posts

192 months

Wednesday 14th August 2019
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I doubt a complete new sump is all that expensive if you want complete peace of mind.

skilly1

2,702 posts

195 months

Wednesday 14th August 2019
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I would buy a new car - just to be safe.

CrutyRammers

13,735 posts

198 months

Wednesday 14th August 2019
quotequote all
jay44 said:
The thread isn't compromised, I just tightened it past the maximum (I don't know the correct way to say this), so the threads are there, there are just too many now which means there's not s tight seal.

Very interesting about the pressure. Didn't even consider that, thank you. I'm happy to buy the helicoil kit, I'm fine to get stuck in but nervous with new things with cars. I'm not sure about the material.. it's s BMW e82 (1 series coupe)
You said in your first post that the thread was ruined, which is it?
Someone else just asked this. Either a new sump (second hand from a scrappy), or drill and tap to the next size up, and use an ordinary bolt and copper washer to seal it. Ebay has all the bits, it'll be better to tap a new thread than use a helicoil IMO, and probably easier.

Chiswickboy

549 posts

188 months

Wednesday 14th August 2019
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CrutyRammers said:
You said in your first post that the thread was ruined, which is it?
Someone else just asked this. Either a new sump (second hand from a scrappy), or drill and tap to the next size up, and use an ordinary bolt and copper washer to seal it. Ebay has all the bits, it'll be better to tap a new thread than use a helicoil IMO, and probably easier.
The disadvantage of tapping out the old thread is that you will need to obtain a suitable size tap and similar size drain plug and washer (which may not be readily available).

Helicoils require a new thread to be tapped so it is probably best to Helicoil and take the thread back to original size. Then you can either use the original sump plug (providing it is not damaged) or buy an easily obtainable one from a dealer.

Some people consider thread inserts (Helicoil is only one of a number of brands for these) as bodges but in reality they are often used to provide a stronger thread during manufacture of aluminum parts in the factory.

There are kits available to recover stripped sump threads which use a threaded sleeve but these are usually for the trade and if you only need one then you finish up with, say, one and having to pay for the other ten that you will, hopefully, never need.



Ilovejapcrap

3,281 posts

112 months

Wednesday 14th August 2019
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skilly1 said:
I would buy a new car - just to be safe.
lol

J50N WA

303 posts

137 months

Wednesday 14th August 2019
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you're looking for a dowty washer.

used in hydraulics.

mickrick

3,700 posts

173 months

Saturday 17th August 2019
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Buy a torque wrench and a workshop manual. And read it.

helix402

7,859 posts

182 months

Monday 19th August 2019
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25Nm.

PaulKemp

979 posts

145 months

Monday 26th August 2019
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Dowry was her would work but as you require a thicker washer Ford used a nylon washer on various sumps and you can buy an assortment of tap washers that have nylon, fibre and rubber washers.

The best way would be to fix the thread problem, on the Ford Escort RS200 sump it’s a simple M10 bolt with a washer so a special sump plug is not needed