Coolant flange leaking

Hi, just looking for some advice please as I have a leak coming from near one of the bolts heads on the coolant flange I have bought an new one, obviously doesn't  come with any sensors, please could u advise me on the sensors I need as there are 3 plugs going into it. Any info would be appreciated. Cheers.
 

Well I hate to tell you but you are going to have to buy a new one.  

That is one of the weakest parts of the system.

You can replace the plastic part with a metal one off a 16V or older pre-90 cabriolet.

I explain it all here:  The original outlay for the flange is going to be a tad bit more, but it will last a lifetime, and the 16v CTS sensor is less flaky than the one you have.

I still hate plastic parts, but thanks Tolusina. | VW Vortex - Volkswagen Forum

Thank you Briano1234 really appreciate that and the link explains everything I needed. I have bought a new one but as u say it's plastic an wont last I'll get looking for the metal one. Thanks again. 

The plastic one you have on the car is probably the original one so it's lasted a few years, fit the plastic one you have so you can use the car and look out for a metal one but finding a metal flange won't be easy or cheap if buying a new flange.

Go carfully undoing the bolts and don’t go mad when you do the bolts up as they can easily snap, give the head face where the flange fits a good clean and make sure it’s nice and smooth and fit a new o ring.

I think your third sensor on the bottom of the flange isn't probably connected as it is being used as a plug.  Over here you can get new flanges with no o-rings or plugs for about 3-4 dollars, but you can also buy the Kit that has the lower plug and all o-rings and clips for 20.

When going back here is a Big hint.
USE A TORQUE WRENCH as the bolts are to be torqued to 87 in/lbs  which isn't much.  To much and you can shear the bolt.

Use 1/4 drive 6pt socket.  

I would buy 2, as you want to have a spare, as my daughter had that break and I ended up having to cluge parts from Walmart to Drive it back home 30 miles….

When I use one (I have two Cabby's) I would immediately buy a spare.

So at one time I had 2-3 spares….  Once I converted over to metal ones from the Junk-yard I haven't had a flaky CTS sensor, or a Broken Flange.  

Also make sure that the metal ear bolt pass throughs are even with the plastic, I had one that I have to file flush to get it to seal.

Thank you both for your advise I'll fit the plastic one I have bought which comes wi new oring so all good there an buy a spare for time being, an keep my eye out for a metal one, defo going to use torque wrench as don't want to shear the bolt or crack the casing. Just one more thing after both mating faces are clean do I need a gasket sealant or is the oring all that's needed to do the job? Thank you.

I did mine the other day. The mating surface on the head was pitted quite badly. I used a diamond file to tidy it up. Only attempt this though if you're confident you can keep a machined like surface. Used flange sealant as a precaution.

Cheers steve I'll remove mine an check for damage pitting etc as you say think a bit of flange sealant just in case won't harm. Thank you.

You don't need to use sealant, I've never used any but if there is some pitting then you may need to, all depends on how regular pervious owners have changed the coolant.

I'll have a look this week cheers mate, I did flush the system soon as I got it an it was nasty so I can't see that it was changed that often so I'll have to see when removed the condition of the mating face. Thanks again all for your help.

Just an update. Changed the flange to new plastic one, mating face pretty good to be fair so no sealant needed i did however inherit a new leak from one of the sensors (red) so replaced 3 rubber orings and jobs a good un. Thanks for all the advise.

Good to hear it's all sorted, check the tension on the bolts in a weeks time and check for any leaks/white power marks.

Cheers mark. I'll have a check next weekend for the things you say. Thanks again.