White residue on thermostat gasket?

Tonight after an extended drive I checked my new thermostat installation, as I have been. Turns out there is still a slight leak.

However, I noticed something unexpected this time.. there was a slight white residue along edges of the Felpro gasket, and a little on the intake just behind it.

There were no other symptoms. My supercharger gradually leaks.. think this could have spewed some oil to cause it? My oil pressure sensor also currently leaks.. think it could have sprayed slightly under heavy boost?

Anyone see this before or have some ideas? I would certainly think if engine oil was that far into the cooling system and oozing out w/ coolant I would surely see obvious signs of problems..

Boy your having a time with this thernostat housing aren't you. Have you tried permatex water pump and thermostat sealer as passed on here before? I used that with a thick homemade gasket and I think I overtighteted the bolts which I tend to do and still no leaks.

i had a cracked radiator hose that was leaking and leaving a white residue all over the fan and everything. i don't know what it is. maybe hard water mixed with the coolant?

The T-stat housing is the biggest pain in the arse on this car I swear! Oh have I been in your situation.

Might want to consider this. Last time I did mine, after dropping my screws that hold it 100 time and having to use 4 extensions just to get to them I said there has to be a better way! Cus even when I did get them in I couldn't tighten them down like I wanted to.

So I screwed in stud bolts and then slid on my housing then tightened the baby down...no leak since! Seriously this is how Ford should have made it to begin with. Now instead of feeling like I need 5 hands, now I just slid it on and tighten the nuts. Way more convenitent!

..as for the white residue...I will go with NMxr7SC's answer...I think the water is what your looking at.

-Tim

The leak certainly has been a problem, though it is at least now minor. I will eventually take it back off and use some gray permatex, probably change the paper FelPro to a Motorcraft in the process.

My main issue now is this white residue. I have driven the car for a total of about 8 hours after the new Tstat housing, and the last 2 hours drive was the first I've seen of it. I use distilled water in my cooling system, it has been completely flushed with it. I did add about a 1/4 gallon coolant after the switch using half spring water, but if that caused it I'd think I would have seen it sooner?

Strange in any case, there was also some muddy appearing substance on top of the water pump where I can normally find the leaked coolant. I checked it again today b4 running, most of the white is now gone, and only coolant remains on top of the water pump.

Could oil be in the area of the Tstat housing w/o appearing in the radiator or overflow?

Why are you supposed to use spring water. I have never used it, and never had a problem,
It almost sounds like your housing is warped , or you are not using RTV silicone . I use the gasket take a razor blade clean the contact surfaces and then apply the silicone and bolt it down let it set over night and , should be good to go.

Tbird1712; you are supposed to use distilled water, not spring. The reason being it does not have minerals to build up within your cooling system and cause a failure.

Also, I replaced my warped housing with another. I did not use RTV, as you should not have to. I previously used copper RTV on my last housing and it eventually leaked anyway. I will probably redo the new housing with Gray Permatex.

But for the time being, my small leak which occurs after shutoff is not the issue. The white residue I am finding around the gasket is.