Welch plugs

[TheChamp]

I have one of those leaking on my sister's 2006 Fiesta 1.4. I need to replace it but can do with some little advice as I've never had to do one before.

It looks like a simple job if everything goes right but in terms of the worst that could happen, if it falls inside is it possible to remove it or is it going to fall into some crevice somewhere resulting in expensive repairs?

What sort of sealant should I use, seems like the previous owner used some silicone which is clearly not working.

 

[sly]

Put some stop leak first and see if it stops, stop putting water into the cooling system..

 

[TheChamp]

Put some stop leak first and see if it stops, stop putting water into the cooling system..

Thanks, the Welch plug are not rusted as the car is on the correct premix of antifreeze, they are leaking somehow which leads me to believe that whatever sealant used there was not right.

Which stop leak? That goo you throw into the coolant?

 

[minkukel]

I have one of those leaking on my sister's 2006 Fiesta 1.4. I need to replace it but can do with some little advice as I've never had to do one before.

It looks like a simple job if everything goes right but in terms of the worst that could happen, if it falls inside is it possible to remove it or is it going to fall into some crevice somewhere resulting in expensive repairs?

What sort of sealant should I use, seems like the previous owner used some silicone which is clearly not working.

Please post a photo of the old welsh plug

 

[Sinbad]

Check on YouTube there seems to be plenty of videos about fixing them.

 

[TheChamp]

Please post a photo of the old welsh plug

I will as soon as I have removed it, the car is not in my possession, I will have to get all the material first before I remove the old one, it is beneath the tappet cover so that means a new gasket and bolts have to be bought along with the Welch plugs.

The car is still working fine, I came upon the discovery by accident while changing spark plugs, I first thought it was oil since that engine has a flawed tappet cover design and gasket, only realised it's antifreeze when I wiped it.

 

[TheChamp]

Check on YouTube there seems to be plenty of videos about fixing them.

Yeah I have googled and I am feeling very confident, I just wanted to cover all my bases.

 

[minkukel]

I actually meant still in the original position

 

[TheChamp]

I actually meant still in the original position

As I said I don't have the car with me but here a video of a similar problem.

 

[Hemi300c]

Done it before. I used Red Indian sealer.
Make sure the hole is clean and smooth before inserting the new plug and make sure you put it in straight and even.

 

[TheChamp]

 

[TheChamp]

Done it before. I used Red Indian sealer.
Make sure the hole is clean and smooth before inserting the new plug and make sure you put it in straight and even.

Where did you buy it?

 

[Geoff.D]

The plugs should not be able to fall into the engine, the design is such that that can't happen through the hole being plugged.
The key is to use an appropriate high temp sealing compound, not any old thing lying around.
The hole MUST be clean and the plug must seat properly before following the installation instructions.

 

[Duke of Hazard]

I did one of these to my first car maybe 15 odd years ago, I don't remember using any sealant but it would make sense to use something designed for this purpose as they re quite a snug fit, welsh plugs should last the life of the engine if the correct coolant mixture is used.

One thing I do remember was struggling my ass off to remove it, if you can find/make a tool to pull it out its well worth the money/ effort and then you can just sell it off on Gumtree afterwards.

 

[TheChamp]

Thanks for all the advice.

 

[Hemi300c]

Where did you buy it?

Auto Zone

 

[Düber]

Some very good advice here, just my 2c worth.

To remove the old one I sometimes (if it is possible) drill a small hole into it and use a self tapper or a small coach screw to pull it out. There are unfortunately a few designs where the plug can fall into the cavity behind it so take care when knocking it, therefore the screw (not in to deeply, just through the plug) with a claw hammer or crowbar works for me.

Some people swear by the Shellac, I use a good grey silicone. Whatever works for you.

When fitting the new one (buy a few they are very cheap in case something goes wrong) make sure that it goes in true and straight, a socket works well, if you are skew there is a chance you might crack the housing at worst or have a leak at best.

Which leads me to my concern, if the antifreeze mix has been good, why is it leaking? Has the plug been replaced before and not been fitted carefully causing a hairline crack in the head? Is it perhaps skew? Was there a time that it was run without antifreeze that caused it to rot?

 

[Geoff.D]

You really have to mangle the old Welch plug for it to be able to fall into the cavity!
Yes, I did not comment on the techniques of removing a Welch plug. I sort of assumed OP would read up on that and know how to remove and replace these things.
My father used to say only a bad mechanic needs to use any sort of sealant when replacing a Welch plug.
I, on the other hand, do use a sealant. Then I made myself really nice little gadget for removing Welch plugs when I worked on engines, which would ensure proper recovery of ones removed, and proper seating and fixing of the new ones. It is actually very rare that one needs to fiddle with them, so your point that the plug must have been badly replaced at some stage is the reason for the leak, which may well be a crack in the block considering most engine blocks these days are some sort of an alloy.

 

[TheChamp]

Some very good advice here, just my 2c worth.

To remove the old one I sometimes (if it is possible) drill a small hole into it and use a self tapper or a small coach screw to pull it out. There are unfortunately a few designs where the plug can fall into the cavity behind it so take care when knocking it, therefore the screw (not in to deeply, just through the plug) with a claw hammer or crowbar works for me.

Some people swear by the Shellac, I use a good grey silicone. Whatever works for you.

When fitting the new one (buy a few they are very cheap in case something goes wrong) make sure that it goes in true and straight, a socket works well, if you are skew there is a chance you might crack the housing at worst or have a leak at best.

Which leads me to my concern, if the antifreeze mix has been good, why is it leaking? Has the plug been replaced before and not been fitted carefully causing a hairline crack in the head? Is it perhaps skew? Was there a time that it was run without antifreeze that caused it to rot?

The car was bought used so no idea what happened before but I see some grey silicone on it, looks like they could have been done before. My investigation is very preliminary as I am yet to open the tappet cover and get a good idea of what is happening, I saw the coolant by chance when I was replacing the spark plugs so the first assumption was Welch plugs.

It's not an awful amount of leakage since it's barely visible on the expansion tank, if they were rusted the car would be loosing a lot of water and the spark plug would be swimming in water.

I replaced the tappet cover gasket last year and there was definitely nothing wrong with the Welch plugs, just spark plugs swimming in oil, no sign of coolant back then. Whatever happened is recent.

 

[Hemi300c]

I reiterate ensure the hole is smooth when replacing. Do not sandpaper the actual body but sand off the dirt/old sealant/rust.
As mentioned buy a few I think they are about R30 +- each.