Thermostat housing

[JOES89K5]

Hello Members What replacement thermostat housing are you guys using on the 350 Chevy 1988-1995 engines. My aluminum housing seems warped and leaks with new gasket. Should I stick with aluminum or go steel. What’s the torque specs on bolts on aluminum housing. Thanks for any input. I have 89 K5 350.

 

[diesel4me]

Standard/Hygrade used to have cast iron replacements available to replace the crappy stock aluminum water outlets..that is what I used..

I don't know the torque specs offhand,but they are likely listed somewhere on a google search...I'd guess about 10-15 ft/lbs max,the bolts are 3/8" and in most other applications they get torqued to about 35 ft/lbs,but a water outlet only needs enough torque to crush the gasket and not let the bolts loosen up..they crack easily,so it is best to be gentle while tightening them,and tighten them equally,not one first,then the other--go back and forth a few times..

 

[dyeager535]

I've taken the housings and run them across sandpaper on a flat surface. Aluminum seems to warp and often pits pretty bad. If its warped, a couple passes on sandpaper will show it. If the intake is pitted terribly, may have issues no matter what you do.

Make sure the mating surface is flat, thermostat flange fits flush, and the gasket surfaces are not overly pitted. I'd just use black RTV instead of a gasket, and I'd do the same (or non-hardening sealant) on the bolts. Then let it dry for 24 hours before putting fluid in it.

 

[Wes Harden]

I would match the intake manifold material. Cast iron outlet for cast iron manifold, and aluminum for aluminum. Helps cut down on electrolysis.
As stated above 10 to 15 ft pnds is plenty. Nice clean mating surfaces. Maybe run a tap through the bolt holes.

 

[Wes Harden]

wow nice gasket, I just make 1 from the box the thermostat came in.

 

[sweetk30]

as said . get your housing FLAT . i go slow and use a file my self . almost every one is warped .

check and flatten the intake side also .

anti-seize copper based on the bolts .

good quality felpro gasket . and i use a super thin almost a coating on both sides of gasket with black rtv just to give it a little sticky . also make sure its dry no anti-freeze on the surfaces .

if junk yard hunting also check the full size vans . i think they run the same t-stat neck to clear the serp belt stuff .

 

[sweetk30]

I bought one of these https://www.summitracing.com/parts/nal-10108470/overview/make/chevrolet and this https://www.summitracing.com/parts/sum-g2399/overview/make/chevrolet

Use some anti seize on the bolt threads.

cant use this housing for 88-up with serp belt . wont clear the bracket setup and molding of the hose .