Coolant leaking at thermostat housing after manifold removal??

[Flexthis2011EB]

Hey everyone. Long time. So, i removed my intake manifold on my '11 flex EB to get to back valve cover, and all reinstalled i noticed my over flow tank over flowing and bubbling so i thought bad t-stat. So i got new one from oreillys, looked nothing like the old one but i tried it anyway. Then when i started the car again the radiator fans were stuck on high speed and coolant started leaking out of t-stat housing. I assumed pressure was building up behind this t-stat i just got from oreillys because it wasnt opening due to it was a 190° and i heard the flexs OE is like 170-180° and also plus it looked different. So i brought it back, went back home and tested the old original one using the pot and water boil method. T-stat opened just fine right before boiling. So i put it back in with new t-stat seal and a dab of water sealant. It was fine for the start, fans were on super low speed (but still on which i found weird), no leaks, but as soon as i drove and came back it was leaking again. I noticed a hairline crack on intake side. Could that be it? Did i possibly torque bolts to housing to tight and warp it? And also i noticed no gasket between housing and manifold, normal? Sorry for long post. All help needed. Thanks.

[Gjkrisa]

Yea first thought is the head gasket is bad. And thermostat didn't open because there is air keeping the coolant from going thru the thermostat to warm the thermostat.
But just taking off the intake manifold I wouldn't think it would cause that. But maybe it's a coincidence.

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[MiWiAu]

Where exactly did you notice the crack? Was it the manifold or the thermostat housing?

Mine did not have a gasket, but there was an o-ring (is that what you are referring to as the "t-stat seal"??). Thermostat in first, then o-ring, then housing. Are you sure the o-ring made it back in (and in the correct order)? Maybe it is damaged? Also, my service manual called out thread sealant with ptfe for the thermostat housing screws - not sure why, but I used it anyways. Also, the torque isn't very high on those screws. I can look it up in the morning if someone else doesn't post it first.


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[Flexthis2011EB]

Yea everything has ran just fine and still does. Never has overheated even now with this problem which is another weird thing. On my dash and on my live data my engine temp never goes over 220°.

[Flexthis2011EB]

Wait, thermostat, oring then housing?? I thought it was oring on inside of intake side, then tstat and then housing? Is this all because the gasket is on the wrong damn side?? Lol and crack is on manifold. More like a small gouge. And i will most def use thread sealant on housing screws now.

quote author=MiWiAu link=topic=7094.msg108463#msg108463 date=1480309574]
Where exactly did you notice the crack? Was it the manifold or the thermostat housing?

Mine did not have a gasket, but there was an o-ring (is that what you are referring to as the "t-stat seal"??). Thermostat in first, then o-ring, then housing. Are you sure the o-ring made it back in (and in the correct order)? Maybe it is damaged? Also, my service manual called out thread sealant with ptfe for the thermostat housing screws - not sure why, but I used it anyways. Also, the torque isn't very high on those screws. I can look it up in the morning if someone else doesn't post it first.


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[/quote]

[pmezo33]

I forget the exact order it goes in since it's been about a year, but if you don't put it in the right order, it will leak.  Ask me how i know.

Switch the side your o-ring is on and see if that fixes it.  Make sure the engine is cool when you open up the housing too.

[MiWiAu]

I got out of bed to check because you made me doubt myself.

See attached.

Confirmed. Thermostat first, then o-ring, then housing. Hopefully this resolves your issue.

EDIT: Also attached the cooling system bleed procedure for your reference.

[pmezo33]

Here's a pic for my MKS from the chilton manual.  I'm sure it's the same for yours.

Looks like thermostat then o-ring then housing.

[Flexthis2011EB]

Man u just saved me from taking the minivan to work tomorrrow. This is why i love these forumn. So sorry for making you get up. Thanks a bunch bro!! And thank you all for your help

I got out of bed to check because you made me doubt myself.

See attached.

Confirmed. Thermostat first, then o-ring, then housing. Hopefully this resolves your issue.

[MiWiAu]

Man u just saved me from taking the minivan to work tomorrrow. This is why i love these forumn. So sorry for making you get up. Thanks a bunch bro!! And thank you all for your help

LOL. No worries. I figured you might be up trying to fix it, and I wouldn't have been able to sleep with a clear conscience without confirming. I added the bleed procedure to the prior post as well.

I'm only 3 months in to my EB ownership, so I'm pretty fresh and have been helped a lot by the forum. It's nice to be able to give back once in a while.

Good luck!

EDIT: Looks like pmezo was on top of it, too! Thanks!

[Flexthis2011EB]

Yes, thank you to everyone who helped. Yall are awesome!! 

[SHOdded]

MiWiAu and pmezo33!

[Brucelinc]

Yes, the above info is correct.  Thermostat, o-ring, then housing.  I had to tug pretty hard on my thermostat because the O-ring was trying to hold it in place.  However, the motorcraft parts diagram shows it before the thermostat.  I don't want this to confuse the issue but I thought it was noteworthy to see.

[ZSHO]

It all boils down to lending a helping hand in any way you can,much appreciated from all above.  Z

[Flexthis2011EB]

Thank you all again!!!! I was able to drive my baby to work with no problems. Lets keep the help alive!! Pass it along!! Everyone have a good day!!