Bathroom silicone to seal thermostat housing?

[Ben Lessani]

Hi guys, my mate brought his car round, Fiat Punto, earlier and his expansion tank was full of crud, so I did a quick flush and his thermostat housing had a gasket on it. Obviously, it fell apart when I removed it, being too late to pick up a new gasket, I just whacked a bunch of silicone sealant around the faces and bolted it back on. I've left it to set for about 30mins to see how it goes...

Is the silicone likely to hold up (will it even stick with the metal), will it melt with heat, can I just leave it, or will it need replacing permanently? I had some liquid sealant from when I did the head gasket - but its all gone, so my quickest hack was to use silicone I had lying about.

I'm about to go start the car and see how it goes...wish me luck!

[new8vgtiowner]

You will need it------maybe if the faces arn`t too bad it might work --replace as soon as you can,its no good for that type of heat-
P.S.----In future make a gasket out of a bit of thin cardboard-much more reliable.

[Ben Lessani]

The faces were pretty uneven, I didn't have any gasket paper (used to have tonnes) so I didn't bother making a gasket for it.

I started the car and it didn't leak at all - so it will do for the next few days I imagine, but I will get him to order a new gasket for it so it will be 100%

[herbster]

cereal boxes are good, due to the wax coating on them, they compress and seal but don't break down for ages! 

[perryqhill]

You never know it might seal ok, but silicone dries and hardens and IIRC the blue stuff I would normally use on gaskets doesn't dry as hard and remains flexable, so supposedly gives a better seal on things like that.

[mattneck(Beavis)]

proper loctite liquid gasket tbh, bathroom silicone just pops clean through again, from experience that.

[Ben Lessani]

Grabbed some liquid gasket today, will change it in a couple of days.

[boneybradley]

hey it's a fiat! it will break again before you have chance to use proper gasket