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Oil leak from bolts on aluminium sump


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Hi all, 

I seem to have a leak on every bolt holding the aluminium sump on place.. :(  It looks as though the oil is seeping down the thread and then forming a drop on the head of each bolt (see pic). I've tried removing the bolts and putting thread sealer on each along with adding a dowty washer, but that still hasn't seemed to have cured the issue.. anyone else encountered this and found a way of making it leak proof?? 

Panch 

IMG_20190804_161805.jpg

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Hi Panch,

Are you using spring washers or flat washers? They look like steel washers.

It is best to use copper flat washers with some sealant.

Waldi

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Hi Waldi, thanks... I've tried spring, flat and now Dowty.. not sure what they're called over your way, but they're the flat steel washers with the rubber seal on the inside. None of them seem to be working sadly..! I've also tried a couple of thread sealants too, and that's not working either.. ^_^

Panch 

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Thanks Mike... but I'm using Permatex High Temp thread sealant already, and in the past I've found that it seals absolutely anything... have you used the Loctite 577 before in High temp environments and had success? 

Thanks Roger, yes checked everywhere else that it might be coming from and it definitely seems to be coming down the threads... even the bolts right at the back on the sump have the same issue! 

I wasn't aware that the alloy sumps had an issue with leaks? Anyone else encounter this as well then? It's pretty much a brand new sump from SC so I'd hope that they would have resolved any historical issues by now?? 

Panch 

 

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Hi Panch, 

 just a few years ago (4 or 5) there were posts about porous castings in both the sump and rocker covers.

However that would tend to be in a specific area and probably not cover all the screw heads.

 

Roger

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If they are all leaking i’d question the gasket?

surely the gasket should stop oil getting to the bolts?

steve

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I've had a similar problem with coolant leaking around the water pump mounting studs, which are fitted to an aftermarket alloy impeller housing on my 2.5 litre GT6. Refitting the studs with Loctite has fixed the leak, as Mike C recommends above.

Nigel

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Panch,

As Steve has said, the bolts and thread areas are irrelevant. The correct gasket with a good quality sealant will solve your issue. The consistency of the leaks from every bolt confirms the issue is the gasket and its sealing method.

Colin

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Let is know how you get on Panch!

be sure to clean the mating surfaces thoroughly, perhaps whoever fitted the alloy sump wasn’t thorough enough.

also, i wonder what the correct torque figure is for the sump bolts with the alloy sump?, low torque setting on the steel sump is partly to protect the sump flange from distortion. Also beware the allow bridges front and back, these strip their threads easily !

steve

Edited by Steves_TR6
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All the side bolts are away from the oil, the only ones you need to seal with copper washers are the 4 I think in the aluminium bridge piece at the front and the rear of the engine, these do go into the oil.

John

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6 hours ago, Panch said:

Hi all, 

I seem to have a leak on every bolt holding the aluminium sump on place.. :(  It looks as though the oil is seeping down the thread and then forming a drop on the head of each bolt (see pic). I've tried removing the bolts and putting thread sealer on each along with adding a dowty washer, but that still hasn't seemed to have cured the issue.. anyone else encountered this and found a way of making it leak proof?? 

Panch 

IMG_20190804_161805.jpg

 

6 hours ago, Panch said:

Hi all, 

I seem to have a leak on every bolt holding the aluminium sump on place.. :(  It looks as though the oil is seeping down the thread and then forming a drop on the head of each bolt (see pic). I've tried removing the bolts and putting thread sealer on each along with adding a dowty washer, but that still hasn't seemed to have cured the issue.. anyone else encountered this and found a way of making it leak proof?? 

Panch 

IMG_20190804_161805.jpg

 

Hi Panch,

That sump looks to me to be to be a gravity casting if so this type of casting is prone to be porous when cast in aluminium? Are there any other oil patches on your sump i.e. between the ribs. You may have to  have the casting vacuum sealed, a common Aerospace procedure to cure this sort of problem.

Bruce.

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For what it's worth I've had a couple of these sumps from new and they were both porous...but I agree with the others, I think it is more likely a gasket issue, plus of course you can't use the original bolts as they are too short

 

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11 hours ago, Panch said:

Hi all, 

I seem to have a leak on every bolt holding the aluminium sump on place.. :(  It looks as though the oil is seeping down the thread and then forming a drop on the head of each bolt (see pic). I've tried removing the bolts and putting thread sealer on each along with adding a dowty washer, but that still hasn't seemed to have cured the issue.. anyone else encountered this and found a way of making it leak proof?? 

Panch 

IMG_20190804_161805.jpg

Hi Panch, I have the same problem but only on 3 bolt heads two on drivers side of engine second & third one back from timing case & one on left side towards the bell housing cured this one with sealant, but unable to stop the other two from leaking.

My thoughts are that it must be the gasket that has not been fitted correctly but now hearing your problem l am not so sure.

What grade oil are using ? since l changed my oil that must of been to thin & replaced with 20/50 it has reduced the leak.

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Richard, I'm using Classic Oils 20w/50 so I don't think it's the oil.

I'm now tossing up between it being the gasket and/or the porosity of the aluminium itself based on comments above. The thing is, if I've got to take the sump off to redo the gasket, and then I find it's the sump itself once I've reassembled everything, I'm going to wish I'd just swapped the sump when I was doing the gasket!! Thoughts on whether I just go back to a standard sump? I thought the additional cooling and the capacity would be a bonus with the aluminium sump, but not at the expense of my garage floor.. :rolleyes:

Panch 

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If you take the sump off run a straight edge along the mating faces to make sure the gaskets are being compressed properly. I went off finned sumps decades ago after reading an article by the  late Phil Irving in a book published by Repco/Brabham  around 1970 - the didn't improve oil cooling during engine operation much at all unless the sump also had internal ribs. Can't find the Repco reference but this link  has Phil's ideas from his book "Motorcycle Engineering"

https://www.google.com.au/url?sa=t&rct=j&q=&esrc=s&source=web&cd=11&cad=rja&uact=8&ved=2ahUKEwikwdbD1e_jAhUGA3IKHe8RB-cQFjAKegQIBBAC&url=https%3A%2F%2Fwww.perfvair.com%2Fapp%2Fdownload%2F5712740%2Fperformancecorvairs_Sample.pdf&usg=AOvVaw1XabJ5_BAq-_iEsNFylDjg

Edited by Mike C
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If the casting appears to be porous:

Porous castings can be made leak-tight by impregnating with water glass, which is cheap, but I do not know if this still works once the metal is contaminated with oil.

Waldi

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