Bronco Forum - Full Size Ford Bronco Forum banner
1 - 12 of 12 Posts

·
Registered
Joined
·
824 Posts
Discussion Starter · #1 ·
1994 EB with the 5.8 L engine
Who is the genius at Ford that designed the thermostat hosing on this engine? What a POS
This is my second time putting it in, and when I go to fill with coolant it leaks like a sieve
I even got a new housing that is nice new and flat
The housing has this shitty shallow counterbore that the OD ring of the thermostat needs to key in on
When you put the whole mess together you have to be careful it does not slip down and out of that shitty counterbore preventing a proper seal
In addition, it only uses two lousy bolts, a third would have been nice

Any tricks for putting this POS together?
Next time around I am inclined to glue the thermostat into that counterbore and then put it all together
Aside from silicone RTV, any ideas for adhesive?
Once its in place it can even dissolve, its no longer needed

I also thought of a crack in the block or intake manifold but it was all fine when I took it apart, so I doubt its an issue

I also have a fiber optic camera I can get in there with and have a closer look at the leak, the leak comes from the bottom of the housing, just where I would expect if the tstat slipped down and out of its bore

.....Any tricks for assembly?
 

·
Registered
1996 Bronco XLT 5.8
Joined
·
13 Posts
I put RTV in the recessed ring to hold the thermostat in place....have never had a problem. You can also take string, run it through the thermostat and out the housing, tie it off with a stick or something... that holds the thermostat in place. Once installed, cut the string and pull it out. Saw an old-timer do that on a Mustang and it worked perfect.
 

·
Premium Member
1982 Bronco XLT Lariat, 351W, C6; 1989 Bronco XLT, 302, AOD
Joined
·
326 Posts
Sit back, cool down, adjust your attitude, then start over. It will be much simpler the next time around.

TB
 

·
Registered
Joined
·
824 Posts
Discussion Starter · #5 ·
Great idea jscheier !
I was pretty much thinking the same and in addition possibly spray some rubber cement of one side of the gasket to use the gasket to hold it into that bore
Your idea easier will hold it in place better
 

·
Registered
Joined
·
1,134 Posts
I always used a dab of gray rtv to hold it from slipping. Used it for sealing too.
One other note - on my custom car with a sbf, I bought a new t stat that had a thicker flange. Figured it out after the 3rd leaky attempt. Ended up rtv/gluing 2 gaskets together. Worked perfectly.
Yes, a 3rd bolt would have been nice, but put together properly the design does work well.
Sent from my Pixel 6 Pro using Tapatalk
 

·
Registered
93 FSB 5.8 EFI E4OD Punisher VB 6" BDS Stage II w/DSS 33" MT 4.10 Detroit TT Locker KN TBS JET Chip
Joined
·
170 Posts
1994 EB with the 5.8 L engine
Who is the genius at Ford that designed the thermostat hosing on this engine? What a POS
This is my second time putting it in, and when I go to fill with coolant it leaks like a sieve
I even got a new housing that is nice new and flat
The housing has this shitty shallow counterbore that the OD ring of the thermostat needs to key in on
When you put the whole mess together you have to be careful it does not slip down and out of that shitty counterbore preventing a proper seal
In addition, it only uses two lousy bolts, a third would have been nice

Any tricks for putting this POS together?
Next time around I am inclined to glue the thermostat into that counterbore and then put it all together
Aside from silicone RTV, any ideas for adhesive?
Once its in place it can even dissolve, its no longer needed

I also thought of a crack in the block or intake manifold but it was all fine when I took it apart, so I doubt its an issue

I also have a fiber optic camera I can get in there with and have a closer look at the leak, the leak comes from the bottom of the housing, just where I would expect if the tstat slipped down and out of its bore

.....Any tricks for assembly?
I can just hear the fcuk shet fkn fcuk!!!
 

·
Registered
95 f-150 4x4 5.8 e4od 05 F250 axles w/4:10's lifted/modded owned since 97 w/28K
Joined
·
332 Posts
ive always slightly twisted the tstat in the neck which kinda locks it in place, and I always used pooky instead of a gasket.
(my tstat threads are studded so mine is MUCH EASIER LOL)

clean surfaces real good, i usually sand/sponge them till they are clean, blast with brake cleaner
clean bolt threads and holes, blast clean
remove enough coolant from the intake manifold so that its doesn't want to seep out when installing
most tstat gaskets are sticky on one side to hold themselves in place on the cap as well as the tstat to help hold it slightly, but not all
i use pooky, install the assembly, and barely finger tight till the pooky just barely wants to be squeezed out (skip if you use a gasket)
let cure according to the style pooky you have if you even used pooky
once cure, torque the bolts down
i usually jack the truck up to help burp the cooling system while its running and keep squeezing the top radiator hose to rid any air bubbles
check for leaks
 

·
Registered
Joined
·
824 Posts
Discussion Starter · #10 ·
Pooky....there's a new one

I suspect (I am still waiting for my 'pooky' to dry) that on my first attempt the thermostat slipped down out of that little counterbore
I went and tightened it and an 'pinched' that OD ring and kind of potato chipped it. It never really laid perfectly flat in the bore after that
Bought a new thermostat and trying for the THIRD time.
Third time is the charm they say....

NOTE: If you look closely at the factory thermostat housing that counterbore is not perfectly circular
at the 12:00 position there is a small clearance for the 'bypass button' that allows water to pass through on some thermostats
Some thermostats do not have a bypass and are perfectly circular
 

·
Registered
Joined
·
824 Posts
Discussion Starter · #11 ·
I was right I think, the thermostat from the first failed attempt got potato chipped and never sat right
New thermostat worked fine
Glue the tstat into the bore with RTV and if you dont have a sticky backed gasket, hit it with some spray rubber cement
Then I even put a schmeer of RTV on the remaining interface and let it sit all afternoon
 

·
Registered
95 f-150 4x4 5.8 e4od 05 F250 axles w/4:10's lifted/modded owned since 97 w/28K
Joined
·
332 Posts
they make spray gasket material thats actual chemical resistant not like glue. i have permatex high tack and permatex ultra copper spray on stand by all the time.

studding the bolts was the best cure for mine in my opinion.
 
1 - 12 of 12 Posts
Top