my thermostat keeps leaking nothing seems to fix it. I have a 160 degree thermostat. the water outlet housing is clean and not cracked. it is a new water outlet housing. I have put in new gaskets as well

 

Using gasket maker with the gasket?

Put gasket maker on the intake, put gasket on it. Put gasket make on the housing, and let it sit 2 hours to start to harden (you don't want it hard, just filmed over and getting rubbery rather than gooey). Then, put more gasket maker on the housing again (new gooey layer), and put housing on intake, put bolts in, tighten slightly but not all the way tight. Then wait another hour and tighten down.

I use Permatex Ultra Black and never have issues using this method - this is the procedure I use for the intake to seal it up as well.

 

i used permatex blue and black with a paper gasket and it still blows a leak

 

Are you sure that the sealing surface is flat? Lots of stock aluminum ones get a little warped eventually and I found out how much by rubbing on a flat surface with sandpaper on it. Cured uneven areas with wide files and finished with finer grit sandpaper. Worked good for me

 

My unit is cast iron

 

Ah, well still maybe check for flatness? Just an idea, cast iron heads warp too
I saw a 91 TA coming into the JY the other day with a crossfire engine in it. Kinda weird, but if you need another inlet, LMK and I can check on it when it comes out

 

I was about to say not warped but my new droid froze. my housing apears to be good, flat, and no cracks. but if you any CFI thermostat housing please me know. this thermostat housing leak is driving me nuts.

 

check that the bolts are not too long and bottoming out
before the gasket is clamped-also check for rusted
threads causing the same condition.

 

where can I get factory bolts just in case they are doing it.

 

for original style you will probably have to salvage some
from a junk car or engine- the bolts have a 3/8-16
thread,any auto parts or hardware store will have bolts
that will work but a lot of those are asian import junk
and i don't use that on my car-you can find quality
north american hardware if you look for it,a couple common brands are "fasco"-a little triangle on the head,
-from canada.Another is "nucor"-a small"n"on the head,
made in usa. There are many others but listing them all
would make a very long post

 

How about link to american made bolts that will have a direct fit to simply things ?

 

forgot to mention ARP bolts-they make all kinds of
automotive bolts here in the US-many are 12 point and
stainless steel is avalible for most too,they might have
a set just for chevy thermostat housings
BTW do you know what car that iron thermostat housing
came from?-might be a '70s vette,i think i have seen
iron thermostat housings on those.

 

it is a CFI NOS (new old stock )