Sump thread repair

[jules18375]

T25 1.6TD G reg. We've just drained the oil to find the sump thread is gone (we've just bought the van ). I've read about the various options for repair and want to get it helicoiled as it seems the best long term solution, but does anyone know how easy this is to do in situ? It doesn't look as if you could get a drill to the correct angle, but I've not seen a helicoil kit so not sure how much working space is required. Anyone had this done? Or does the sump have to be removed? Any idea on what I should be paying for someone to come out and do this (we're near Reading)?

[tforturton]

This subject has been covered before. Try searching on 'sump plug' or something similar.
If I remember, it is possible to tap the hole, and then use a slightly larger plug (though can't remember which one, sadly).

[quattrodave]

I would just tap out to slightly oversize and fit an m15 sump plug.
You can buy repair kits with taps and oversize bolts and washers on eBay.
Just search "sump bolt repair"
Good luck, I'm in a similar position to you having just bought my van last year. It seems like previous owners just haven't bothered to do things correctly and I'm picking up the bill now!

[DoubleOSeven]

Yup. The first year is the hardest year, but you'll know your van like the back of your hand when the year is up. We've all been there. FlIp-Side...The van will just get better during your ownership.


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[colinthefox]

As your van is a diesel, I don't think the first two replies are relevant.

The diesel sump is easy enough to remove with the engine in situ. The thread can then be helicoiled by a workshop as long as the casting isn't broken.
You will probably find that the sump plug will leak a bit because the new thread won't be quite true. In that case don't overtighten it. You could then use a smear of silicone on the tapered seal every time you replace the plug.

[jules18375]

As your van is a diesel, I don't think the first two replies are relevant.

The diesel sump is easy enough to remove with the engine in situ. The thread can then be helicoiled by a workshop as long as the casting isn't broken.
You will probably find that the sump plug will leak a bit because the new thread won't be quite true. In that case don't overtighten it. You could then use a smear of silicone on the tapered seal every time you replace the plug.

That's my question really - I know the different solutions (helicoil, enlarge it to an M15, stick a sparkplug in it!) but was wondering about what needs removing to get it done. I don't think you could do it in situ without taking out the thin metal undertray (is that what it's called) or going one step further and taking the sump out so that someone can do it in a workshop and make sure it's square etc.

[Mr Bean]

Probably not relevant in your case but I had a stripped sump plug thread on my 1.2WBX and posted on it not too long ago. Can't find it though.
I considered a helicoil but didn't want to remove the sump and wasn't too confident of the comparatively fine thread in that cast aluminium.
So I found the Metric course thread which enabled a full tread depth in the hole and used a first stage tap in a long series tap holder to maintain correct alignment i.e. perpendicular to the sump casting aperture. I then poured the old oil through the engine a couple of times to was any swarf out and fitted an allen head cap screw which neatly fitted in the existing counter bore and captured a home turned soft plastic washer under the head. I guess an "O" ring would similarly be trapped but ....
As I said probably not relevant but whichever method you use the thread must be perpendicular with the aperture particularly if you are going to use the ridiculously hard copper washer some provide.
CS

[Mr Bean]

Probably not relevant in your case but I had a stripped sump plug thread on my 1.2WBX and posted on it not too long ago. Can't find it though.
I considered a helicoil but didn't want to remove the sump and wasn't too confident of the comparatively fine thread in that cast aluminium.
So I found the Metric course thread which enabled a full tread depth in the hole and used a first stage tap in a long series tap holder to maintain correct alignment i.e. perpendicular to the sump casting aperture. I then poured the old oil through the engine a couple of times to was any swarf out and fitted an allen head cap screw which neatly fitted in the existing counter bore and captured a home turned soft plastic washer under the head. I guess an "O" ring would similarly be trapped but ....
As I said probably not relevant but whichever method you use the thread must be perpendicular with the aperture particularly if you are going to use the ridiculously hard copper washer some provide.
CS

[Mr Bean]

Reading my previous response again I realise that my comment re fine thread could be taken in connection with spark plug threads in Aluminium cylinder heads. This is not the case with the usual long reach plugs where the length to diameter ratio is circa two to one.

CS

[boatbuilder]

Are the threads completely gone or just messed up a bit? I just got the correct sized tap, cleaned out the threads and fitted a new sump bolt.

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[jules18375]

Well, here's the outcome. Got a mechanic to come out to us and for about £95+VAT he re-threaded it and put a bigger plug in it. No need for sump to come out, just needed the undertray unbolting to allow access.
That was the good news. The bad news is that it leaks. Ever so slowly. Literally 1 drop every day, but still a bit irritating. They didn't promise it would work, but still I'll give them a ring and see what they say. 1 or 2 drops a day is hardly a lot of oil and we've just taken it on a good run and it didn't change much when it was hot.

Just a bit irritating to pay good money and not have it all sorted.

[Mr Bean]

I did mention in an earlier post that it was difficult to ensure that the new thread is completely perpendicular to sealing surface of the thread. I would guess that this lack of perpendicularity is leaving a very slight gap on one side of your sealing washer. This would almost certainly be the case if using a copper washer as these really need to be softened by heating and plunging in oil or water. Although I still don't think it makes them sufficiently soft/malleable in some cases.
When I tapped mine I turned up a thickish plastic washer on the lathe which did the trick. Maybe you can try the softening process on the washer your man fitted providing of course it is copper. There are rubber bonded sealing washers available made from steel with a lipped rubber seal molded round the inside although a faf to source. An "O" ring is not really satisfactory unless it is constrained within a grove or pocket.
Pain in the butt to have to drain and refill the oil though
CS

[jules18375]

I did mention in an earlier post that it was difficult to ensure that the new thread is completely perpendicular to sealing surface of the thread. I would guess that this lack of perpendicularity is leaving a very slight gap on one side of your sealing washer. This would almost certainly be the case if using a copper washer as these really need to be softened by heating and plunging in oil or water. Although I still don't think it makes them sufficiently soft/malleable in some cases.
When I tapped mine I turned up a thickish plastic washer on the lathe which did the trick. Maybe you can try the softening process on the washer your man fitted providing of course it is copper. There are rubber bonded sealing washers available made from steel with a lipped rubber seal molded round the inside although a faf to source. An "O" ring is not really satisfactory unless it is constrained within a grove or pocket.
Pain in the butt to have to drain and refill the oil though
CS

Yep, I wouldn't have done it myself for that very reason, but hoped the mechanic could do it. It's leaking so slowly that I will just leave it for now, but when I change the oil next time, I will have a look at the washer in more detail. I think he put two copper washers in. not sure why. I'm a chemist so I might try the heating and cooling process on the washer if all else fails. Thanks for your help

[tobydog]

Try some PTFE tape on the last threads under the head of the bolt/plug to seal the thread?

PS
Wrap it on the right way so that it doesn't unwind as the plug is screwed in.