For some folks that may have developed a small leak and wondering where it is coming from, chances are, it may be from the Coolant sensor housing or Coolant house flange as is is so called. Certainly if you are loosing small amount of water and no immediate visible signs are apparent

Leak's start occurring because the housing rubber seal gives up over time.

I found this out when my car started over heating badly in traffic caused by a couple of things. Firstly the leak in the housing that reduced the cooling fluid and then as the car started getting hot the fans were not cutting in and thus causing rapid surge in heat. Fixed fans(top fuse box issue) and then went about replacing housing which i will show few pic and instructions on.

I already have top engine cover removed, and when removed the small front engine cover to expose Coolant Temp sensor and housing I could see where coolant had been leaking.

Good thing about keeping car and engine bay clean, I can see straight away where a leak is

I could see coolant marks / spots on the side of my cylinder head. (note SAI valve removed makes it easier to see also)

Gear and linkage also soaked in coolant.

This is what a a bad one looks like, can see rubber seal has packed up.

This is the new replacement one P/N 06A121132AP (less than £12 from TPS)

To remove old one you need to get at the gearbox side of the cylinder head. locate the temp sensor and pull out the clip holding sensor into the housing. You will loose a little coolant.

removed temp sensor

You can leave connected and put to one side

Then you need to pull off 3 hoses from the housing(one at each end and one at the bottom. If you have std hose clips, you will need some mole grips or adjustable wrench/pliers to compress the hose clip and slide along off the housing

pic of the 3 hoses

Then remove the 2 allen bolts (top and bottom)

Clean up area around the housing to ensure a good seal.

Replace is reverse.

Be careful not to over tighten and not to crack the plastic housing, the rubber seal will do it's job to stop water loss.

test for good seal and no leaks before you re fit covers.

hope this helps......

Sorry to bump an old thread but thanks for that.

Mine has just started leaking Today :(

Sorry to bump an old thread but thanks for that.

Mine has just started leaking Today :(

 

you are welcome, glad these threads still help folks  :clap:

Yep. Done mine yesterday. Slightly more difficult as mine still has the sai in place. All done and problem fixed anyway, part number certainly helped as I turned up at TPS on Christmas eve Morning!

Fair play for the how to, I'm gonna tackle mine and I'm sure years from now people will still use this thread! Thanks

yeah, like me. I'll be doing it in 2 days when the part arrives. From a slight leak, it's suddenly turned into a big leak and I have to load up with coolant after 30 mins of driving. I blame a 292 mile trip on the hottest day of the year...pushed it over the edge...

About 2 months back I was getting the coolant light coming on regularly, doing my head in, so I did a flush, and used the proper G12 red stuff. Good move, as it left a telltale residue...around the CTS area, so I ordered the flange (06A121132AP). I really hope it's just this that's leaking and nowhere else, or I'm going do something rash