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2006 Mustang V6-Nasty coolant leak.

48K views 17 replies 9 participants last post by  Luis_Mustang07 
#1 ·
Hi everyone, thanks in advance for your help with this.

My friend's 2006 V6 is leaking from this black plastic thing that is located directly beneath the throttle body. Is this the thermostat housing? I'm really not used to a thermostat housing looking anything like this thing. There seems to be two pieces to it (a top and a bottom) and there are a few hoses of varying sizes running to it from the radiator, to the block, etc... It is leaking coolant like crazy out of the driver's side. There was some grayish goo the seemed to have melted out of it also. Is there a gasket in there between the top and bottom that could have failed? Or should I just take it apart and rtv or silicon the two pieces back together? This seemed to have happened out of nowhere. There doesn't seem to be any coolant in the oil or any other leaks.

I tried searching the forums but I really couldn't find anything specific. I am going to buy the haynes/chiltons manual, but I already know there is a good chance that they aren't going to be much help with this. An internet search yielded some odd results as to whether there is a gasket in there or not.

Thanks again!
 
#2 ·
This is very common for the mustangs. My 2000 was leaking in the exact same place. it's cheap plastic. It's called the intake manifold, and someone may have tried to RTV it from the inside. Thats what that gray stuff might be. You will need to replace the intake manifold. Do not try to repair it.
 
#7 ·
This is very common for the mustangs. My 2000 was leaking in the exact same place. it's cheap plastic. It's called the intake manifold, and someone may have tried to RTV it from the inside. Thats what that gray stuff might be. You will need to replace the intake manifold. Do not try to repair it.
S197 Mustangs do not have a cooled intake manifold like earlier Mustangs.
 
#3 ·
It is the thermostat housing, i had the same thing a couple months ago, its very easy to replace yourself. Let me kno if ya need help.

lemme kno where the break is too cuz i have my old one, we can compare

O and yes there is a gasket, i would suggest jus replacing the piece, its like $60, u can switch the thermostat itself to the new housing.
 
#4 ·
Thanks for your replies.AJ- it definitely isn't the intake manifold, but thanks for your help.xchris- it is leaking at the seam between the top and bottom pieces of the housing on the drivers side. The whole seam is leaking on only that side. Since price isn't a problem I think I will just pick up the whole housing (top and bottom pieces) and replace them rather than screw around with trying to fix or seal something that has obviously failed. Did you have to get the housing from the dealership?
 
#6 ·
Im turbo'd so i had to do alittle more then you did, i did get the part from the dealership they also supplied the gasket (i think they gave me two but i only needed one) I wouldnt even call it a gasket, its like an oversized O-Ring

I put RTV sealant around the whole thing just incase (the high temp gasketmaker rtv)

I had to take off the throttle body and some other air inlet tube was in the way for me but i dunno if it would be on your car. Its very simple, i would pick up one of those chilton manuals though, i have one and although it misses out on alot of things i;ve needed its also come in handy as well
 
#9 ·
Did you do it yet?
 
#10 ·
Done.

I changed it out, the housing had pretty much came apart on the driver's side. It is glued together plastic, so the gray goo that was on it must have been that glue.
I rounded off the back bolt that holds the housing to the block, so that was a major pain in the ass. I ended up pulling off the intake manifold so I could drill the bolt and got it out with an extractor bit.
When I first put the new thermostat housing in, I forgot to use the old o-ring (basically a black rubber band) so it leaked, that's when I rounded off that bolt.
When I installed the housing for the second time I used black high temp RTV at the block to make sure it wouldn't leak. I also used the RTV on the temperature sensor that goes into the top of the housing, because that was leaking as well. I probably should have just changed the o-ring out on the sensor, but I just wanted to get this done. (It was almost 100 degrees outside when I was doing all of this.)

So yeah, what a pain it was to change this part that really shouldn't have failed how it did.

Thanks for your help and take care!
 
#13 ·
I fixed it, everything went good! i ended up spending like $90 in the housing, the gasket for it, the thermostat and the gasket for it. all the gaskets were sold sepparately. i have a friend that works at Ford so i got the whole thing really cheap! maybe i did not have to replace the thermostat but i went ahead anyways, they go bad too. Also, i checked out the part and it looks that it busted from the side, like where it has the unions and some sort of glue attaching all the sections of the part, not from where the gaskets are at. By the way, make sure you use the right tools, i see why potatoofdoom rounded off the back bolt on th part, make sure you take out the intake manifold so you have more space to take the screws off.

Thanks for all the posts.
 
#14 ·
#15 ·
The thermostat housing on the Ford 4.0 SOHC V6 is a true marvel of piss poor engineering! It is the last part in the world that should be made from plastic, and two pieces on top of that! It is exposed to heat, cold, pressure, chemical, vibration, and the mechanical stress of being bolted to the engine. They will eventually fail on every engine out there due to the nature of plastic and how it deteriorates over time. I am on my third one after 144,000 miles.

The two pieces are not actually glued together they are assembled using a process call sonic welding in which the parts are put in a fixture then exposed to pressure and very high frequency sonic vibration that causes the two sides to literally melt together.

Another area they are prone to leak is around the temperature sender that is fitted in the top. This is sealed with an O-ring which will fail over time and since the thermostat housing is a plastic part the O-ring sealing surface can vary quite a bit from on part to the next and can also change size over time which all lead to leaks. The O-ring is not available from Ford but you can find one that may even fit better than the stock part at your local hardware store.
 
#16 ·
This helped find the problem on my sister's v6 2006 mustang and I didn't have to remove the throttle body just the hose that goes into it. I don't know a lot bout cars but this helped my find the problem. when we took apart the housing the thermometer was broken and the seals were also broken but it was about literally a 30 minute fix for me.
 
#17 ·
I don't believe I removed the throttle body the first go around I had, however you certainly can if you like having extra room. I did indeed remove the intake manifold in order to get to the back bolt that I stepped. I had to drill into the bolt and twist it out with an extraction bit, that was an extra step that I hope most people won't have to go through. Just be careful with those bolts, use the correct tools and take your time.
 
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