DFlintstone

Good idea if you have another housing. I think you could tighten it enough with one finger hooked on a wrench. How frustrating! Good luck!

bullheimer

torque values are pretty much universal, to a point, and depend on the diameter of the bolt. only variation that i have seen are with longer bolts, such as head bolts, to allow for stretch. if you google torque values you will be able to find a chart.

also, those chrome ones really do blow sometimes. the last time i used one i had the same problem until i ran a flat file over the bottom several times.

with silicon sealer you don't need to over tighten at all. but i hate using it on the thermostat housing cause it just seems to suck for some reason. i like to use just that aviation 300 or some other old school gasket sealer by permatex

even then, i am pretty sure i Sh#! canned the chrome one, painted a stock one, and never have had a leak since. the chrome ones are made out of cheap crappy pot metal.

highmileage

had a thermostat housing warp on me once nothing a mill file couldn't fix. Just don't take off to much material.

cherokeelaredo'90

I put on my old original thermostat housing, new gasket, sealer #2, anddddd it still leaks.. do you think the problem could be the hook up to the housing? I'm talking about where it mounts too on the block, do you think that could be warped? or could it be that i shouldn't use any sealer and thats my problem?

cherokeelaredo'90

or may it be that i'm tightening it too much so the sealer is just seeping out and not doing its job?

Mmurdock

What are the condition of your hoses? I have had problems with old hoses not sealing correctly no matter how tight the hose clamps were.

Have you completely cleaned the machined surface on the block where the housing bolts too? If not get it spotlessly clean and look to see the block has a hairline crack.

Clean your housing throughly and check for cracks. Don't just look at the machined surface, check the entire housing. It's possible you may have cracked both housings at this point it's easy to do if the thermastat slips while tightening the housing bolts.

The housing is made of either pot metal or aluminium and there is a small chance it could have corroded internally and has a pin-hole leak. Look inside with a flashlight for any signs of pitting or corrosion.

Look at the machined surface of the housing and check of any gouges which may have been caused by scraping off old gasket material. If there are any tape a sheet of 120 grit wet/dry (the black kind) sand paper to a thick piece of glass or a large, flat ceramic tile, and wet sand the machined surface until the gouges are gone. This process will also elimate the chance the housing is warpped.

Finally, check the length of your bolts. Are they bottoming out before the housing is fully tightened?

With the machined surfaces clean, flat and free of cracks, use a fresh gasket, a small amount of blue RTV (on both sides of the gasket), and reinstall. Make sure the thermastat doesn't slip by maintaining constant pressure on the housing while you install the bolts (you might need a friend to hold it while you tighten).

KD3NE

Try another dry gasket, this time use this with it this...



http://www.permatex.com/products/aut...et_Sealant.htm


We had a leaking water pump. installed it twice using various sealant combinations to no avail.

Bought a new dry gasket and used the Permatex High Tack SPRAY Adhesive

Important to use SPRAY as it insures an even coating.

thakmfb

just go get a new t-stat housing at napa or advanced I think they are $15. you probably spent that in gaskets and sealers

mmattern1985

Your housing is warped this same thing happened to me I went through 4 gaskets in a row before I bought the housing and it fixed the problem. A 20 minute thermo change turned into 4 hours. The housing was only like 15 bucks at autozone. I should have just bought it to begin with. My problem was that the thermostat wasn't seated all the way when I tighter it down the first time and then when it leaked and I tried it again making sure it was seated I had already warped the housing just a hair to make it leak.

Cherokee89

I had the same problem today. Was going to replace my thermostat on my´90 with a new one, just take off housing, remove thermostat and gasket, clean, put on a new thermostat and gasket and mount it all up.
And leaking, take it apart clean, new gasket sealer asambly again, fill water and leaking.
Take it apart again and start to check whats wrong. Found out the housing is wraped. Why? No overtiting of bolts so something else must cause it.
Start checking out the thermostats how they seat in housing.
Found out that my new thermostat is riding in the housing because a slight differnce in design ( the arch on top is wider and higher ) and because of that the housing never can get flat with the mounting surface of the head, easy to check if you only mount thermostat and hold housing at head then you can feel it ride on the thermostat and not flat.
So I got to my spare ´88 engine, took of the housing and thermostat, checked the thermostat in boiling water ( was the original small arch type )
mounted it all on my ´90, fill up with water and no more leaks.
So original thermostat housings on Renix 4.0 engines can only use small arch thermostats, but if you buy a new one they may have redesigned them to accept the bigger arch termostat.
BTW my new thermostat was an Stanton, have used them before on other American cars without issues.

cpnwrench

Howdy, reading your posts here, and I understand your frustration.

as another piece of advice try to do the following and take your time,,,

once you have the thermostat assembly apart, and all the mating surfaces are dry... stuff a small rag into the head at the housing, then after you have removed all previous sealant with say a soft blade putty knife or even a plastic ski waxer scraper, take some 180 grit sandpaper (small piece) and using say a very small block of wood and wrapping the sandpaper around it, use the sandpaper (u will probbly have to use several pieces), sand , sand, sand, until the face of the housing on the head is shiny. Then take a wet rag (water is ok, but if you wish to use a solvent thats ok too, I use brakekleen on a rag) and wipe any and all traces of what you sanded off that face ... then do the same for the housing.

with the housing what I did was staple a full sheet of 180 grit sandpaper to a plank or table then using a circular motion I took the thermostat housing and face down on it sanded and sanded and sanded until I had a shiny flat surface. Again clean with water then solvent(if you prefer) on the face. Also make sure you clean out the machined recess in the housing!
Once you have these surfaces shiny and flat and free of contaminates, here is what I did to ensure a good gasket seal.......

(I used the gasket which comes from the new thermostat part, but how you want to continue is your call),,,,,

I used the blue RTV, a thin bead on the thermostat housing making sure you surround the holes, then lightly ( very gently) apply the gasket to that bead on the face of the housing, and press using fingertips gently all the way around it, then I put the bolts backwarks through the thermostat housing firmly, not gonzo, but firmly and let that configuration sit on a table, workbench, wherever in a level and flat position ( am thinking the themostat must be installed to that side before you apply the gasket itself as it has the recessed machining for the thermostats rim.).

Once it has set up ( i let sit 4 hours, but thats me).......

I then applied yet another thin bead of blue RTV to the gasket side which will face the thermostat opening in the head. ( after removing the bolts you put in to hold the gasket in place).

Then slowly attach the thermostat housing with the stat and gasket and rtv on it to the opening and slowly install the bolts and torque to 18 ft. pds.

Let it sit overnight.

do your filling etc....and run it.....if it still leaks,, at ONLY the mating surface or from the housing, you may have a hairline crack that leaks only when the metal expands due to heat... in that case go to a junkyard or rockauto.com and get a different one and do the same procedure...
if it still leaks then its possible you have a crack in the head at the thermostat hole...thats a manganflux job to determine an if so it can be fixed with a good metal epoxy by the shop who ran the magnaflux.
Hopefully you wont have to go that far.

good luck sir, hope this helped you some.

cpnwrench

mmattern1985

Just buy a new housing its only ten bucks don't go through all the sanding and rtv stuff simple fix don't make it harder then it needs to be

oopee

same thing happened to me. after going through 3 gasket from autozone, i just went to kragen (advanced auto parts in other areas) and they sold me a gasket with a peel off sticky side and seemed to be a little thicker, placed it on(easier to place on the housing and not having to worry about it sliding off). I have no more leaks after. also have a Honda prelude, same thing..

also the price from autozone was 1.99
kragen was .99

oopee

also, I brought 2 from Kragen just incase it failed on me but didn't. so if u or anyone here planning on changing out there thermostat, I have an extra gasket, free.. just pm me an address.

Tango 22

This stuff works wonders! Dry gasket sprayed with this stuff is my 2 cents. Wish they still sold it in the can with the brush. The spray stuff above was the only way we used to slide and ride the Dodge Neon 2.0L head gaskets and get em to actually seal. Liquid magic in a can I believe.