Leaky sensor

[sierraman]

Replaced the incontinent Thermostat housing on the Mondeo, sorted that out no problem, however it's manifested in another new issue. The temperature sensor is a push fit in the top of the housing held in with a clip. Shit idea I know.

 

However it's now leaking as the O Ring that seals it has worn away, I've wrapped it in some PTFE tape which has stemmed the flow somewhat but it still has a bit of a dribble. In the absence of any suitably sized O Rings would some high temperature Silicone work in this instance?

 

K Seal wouldn't I don't think given the nature of how it sits in the housing and therefore has slight movement.

 

Needless to say you cannot buy the O Ring separate and the switch is £20.

[Kiltox]

Checked eBay for the sensor? Usually much cheaper (£3-£4 for VAG stuff)

 

They might be a bit crap but the o-ring won't be....

[sierraman]

I'm hoping to do that at some point but could do with using the car quite a bit over the weekend, hence if the clear silicone stuff that's high temp would work to get me by. Could do without an impromptu breakdown through it overheating.

[Guest Hooli]

I'd go down any semi-decent car spares place & match the O-ring up. I even got a box of 200 assorted ones from lidl t'other year.

[egg]

You're right it isn't listed as a separate part...

 

https://www.catcar.info/ford/?lang=en&l=bWFya2V0PT1ldXJvfHxjYXRfaWQ9PTcwNHx8Y2FiYnI9PUdEfHx0aGs9PTB8fHN0PT02MHx8c3RzPT17IjIwIjoiRXVyb3BlIiwiMzAiOiJNb25kZW8gR0QgMTk5Ni0yMDAwIiwiNDAiOiJBWUUgWmV0ZWMgRSIsIjUwIjoiQVlFMDQgWmV0ZWMgRS5FbmdpbmUgQ29vbGluZyIsIjYwIjoiQVlFMDQwMjAgVGhlcm1vc3RhdFwvSG91c2luZyAmIFJlbGF0ZWQgUGFydHMifXx8YWxwaGE9PUFZRXx8Z3JvdXA9PUFZRTA0fHxzZWN0PT1BWUUwNDAyMHx8c2V0PT1BWUUwNHx8aW1nPT1EMDAxMTA2MzA1fHxmMTI9PTEwNTUwMDgwKzI4OA%3D%3D

[sierraman]

The earlier 'two sensor' housings had 2 brass switches that threaded into the housing. Then some idiot that ought to be strung out, decided it would be much better to have the sensor an interference fit held in by a clip.

 

I'll pop in the spares shop on the way home and have a look, it's about 8.5mm dia, if I cannot get one I'll stick a bead of RTV sealant round the shank of the sensor and some more PTFE tape then put it back. Should hold it I guess. I tried using Hylomar Blue but in this instance it did not work, maybe I didn't use enough.

[sierraman]

Hang about... Toolstation sell packs of O rings for £2.15. I'll go there and get a box. I'll try that and a bit of RTV and see how my luck goes...

[egg]

HBoL suggests just sealant anyway!

 

[sierraman]

That's on the earlier 'two sensor' unit. One was for the gauge, the other was the CTS for the ECU. That's the type that will be fitted to yours, the one I'm working on is a black top.

[sierraman]

Managed to get some o rings from Toolstation for a whopping £2.21 for a set of 120 or so. Went to a run round the block and it was still leaking, the actual housing won't sit flush I've seen against the cylinder head, it's pissing out there, then to top it all the plastic round the clip for the sensor just fell off.

 

Mad wasn't the word... it's got a 2 year warranty, it wouldn't pass the criteria for a 2 minute warranty...

 

Ended up refitting the old housing with copious amounts of gasket sealer round where it attaches to the cylinder head. So far so good. This is what happens when you try to do something properly.