2.5di Cylinder Head Water Adapter Help

[TransitSi]

Hi all, new to the forum and after a little advice.

The water adapter that screws into the front of the cylinder head has rusted (vans been sat for a few years) and had no choice but to drill out the old adapter but want to retap the threads can someone tell me the tap size please if possible?

[MinorMatt]

I *think* its 1/2BSP but not entirely sure

[TransitSi]

Would that be the bore size for making a complete new thread in the block? I have a couple of new adapters that screw into the block and then the water pipe attaches and the thread is 16mm on the adapater.

Just wanted to make sure before going out and buying a more robust tap and die kit as i only have upto 12mm.

Thank you

[MinorMatt]

This is the correct part

https://www.ebay.co.uk/itm/203293231852 ... SwqNBgPUZp

You could buy it and measure the thread to confirm prior to installation?

[dumper]

I *think* its 1/2BSP but not entirely sure

Not sure on size allways get mixed up with bsp but I’m sure it’s bsp and not metric

[TransitSi]

I do have a couple of the item you listed above and when i use a set of digital calipers on them the thread size is just a shade over 16mm think im going to have to just buy a larger taper set and use it on some old metal 1st to get the correct size.

1/2bsp is looking online around 19.8mm give or take?

[MinorMatt]

Might be 3/8 BSP then.

3/8 BSP major dia is 16.66mm, with 19 TPI

[V184]

This is the correct part

https://www.ebay.co.uk/itm/203293231852 ... SwqNBgPUZp

You could buy it and measure the thread to confirm prior to installation?

i would buy a couple of these and try and thread them into the head unless you've completely killed the old thread ?

[TransitSi]

Small update.

So old thread was gone because transit had been sat for ages in storage, and during the time in storage someone had taken a couple of small misc parts off the engine and also broke the adapter that goes into the head, so we tried to get it out but it was in real bad shape and just would not budge no matter what we tried. So the only option was to drill out the thread but in doing so killed the thread inside.

So i went and bought a 16mm /1.5 tap set and got some old steel and tried it out on that first and it was just ever so short off what was needed for the adapter to screw freely into the new tapped thread in the steel so i went to another shop and took the adapter and bit of steel i tapped with the 16mm and had a word with the bloke there after sizing up with a couple of taps the 11/16 looked the best for what was needed.

Drilled another hole into abit of steel and then tapped it with the 11/16 and tried the adapater and bingo, its worked. So now to take it to the head and hope i get the same outcome!