Corsa sump thread repair ?

Corsa sump thread repair ?

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Discussion

blade7

Original Poster:

11,311 posts

215 months

Saturday 5th April 2014
quotequote all
I was planning to change the engine oil in an 05 Corsa but a previous owner has damaged the drain hole thread in the alloy sump, surprisingly the silicon he used has kept the finger tight plug in for the last year ranting anyway I'm undecided whether to let a garage repair it or use an oversize tap and plug kit from ebay, seems odd the kits don't come with a drill or isn't it necessary to drill before tapping ?

CrutyRammers

13,735 posts

197 months

Saturday 5th April 2014
quotequote all
Ideally you'd drill it out to a smooth hole again and retap from there. Running a larger tap through the existing thread will be pretty shonky.

blade7

Original Poster:

11,311 posts

215 months

Sunday 6th April 2014
quotequote all
The original thread is M14, drill size for M15 is 14mm so it could work in ali I guess ?

stevieturbo

17,229 posts

246 months

Sunday 6th April 2014
quotequote all
Depends what size step you're going to.

And as alloy is soft, often running a bigger tap in without drilling is pretty easy and works no problem.

Or fit a replacement sump

Steve_D

13,737 posts

257 months

Sunday 6th April 2014
quotequote all
If a kit has been developed for it then I suspect this is a common problem.
As has been said, from an engineering purist point of view then a drilled hole would be best.
Sounds to me like that kit is the way forward.

If you are doing the job with the sump still on the car then start by pushing some general purpose grease into the drain hole trying to form a wall all around the hole on the inside. Then coat the tap with as much grease as you can. When you have completed the new thread get a thin piece of wire and hook the grease back out of the sump. This should bring with it most of the swarf.

Steve

Crafty_

13,248 posts

199 months

Sunday 6th April 2014
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There are brand new sumps on ebay for £20, doesn't seem worth the time buggering about drilling/tapping things

blitzracing

6,387 posts

219 months

Sunday 6th April 2014
quotequote all
Ive not seen the Corsa plug and if its big enough , but having had the same issue on another car, I simply bought a new sump plug, and drilled and tapped it out to take a smaller set screw in the centre of the sump bolt as a drain bolt. Having drained the oil, I then jacked the car to stop any more oil running towards the damaged thread area, and cleaned the hold out with cellulose thinners to get rid of any oil traces and then glued the sump plug back in in with JB weld. Not had an issue since, and no nasty swarf in the sump.

blade7

Original Poster:

11,311 posts

215 months

Sunday 6th April 2014
quotequote all
Thanks for the replies. A new sump sounds ideal but I think the exhaust has to come off and as it's original I don't fancy doing that. As I'd be doing the job on my drive on my back I'm inclined to let a garage at it if they will do it for £50ish. If they wont it's a oversize tap and plug job I reckon, at least the sump is empty now.