Thermostat housing leak

[emsvitil]

I found another leak point. The cylinder head corrodes at where the thermostat housing goes:

http://www.focusfanatics.com/forum/showthread.php?t=303682


Ultra black RTV smeared on the head (after removing corrosion), the thermostat housing groove (before o-ring), and over the thermostat housing and o-ring fixed the leak.

[amc49]

You musta had a Tempo or Topaz in your past...........quit stealin' my tricks!

[chadr]

Originally Posted by chadr

In March of this year I replaced the housing and found it leaking again today. I don't see any oil leaking from the valve cover gasket area (but I don't suspect leaking oil from above would damage the housing or seal anyway).

I bought the Dorman 902-201 Water Outlet Housing Kit from Amazon for $35 shipped. I also used Permatex Right Stuff in addition to the gaskets in housing. 9 months and its leaking already. I've never had any leak from anything I've sealed with Permatex Right Stuff.

Maybe I'll go with the o ring (VICTOR REINZ Part #C31611) suggested above and keep the same housing if it appears ok.

I think I'll have to take the blame for this one... I took off the housing and found the permatex sealer was leaking. I didn't use the o ring when I did this job the first time. I don't think I filled the slot completely which led to the leak.

I used the o-ring this time. I filled the o ring gap with sealer completely, then pushed the o ring into place. Spread a little sealer on the surface of the head just to be safe and bolted it back into place.

[MarkZX3]

Well. I'm back and I'm still dealing with the leak. The new seal did work but it to gave out. The problem isn't oil, the problem is the way the housing seals! Its the worse sealing design I've seen.
Here is where I'm at with this problem.
I took a good housing,
cleaned it real good,
filled in the groove for the seal with 5 min Epoxy,
Sanded it down on a FLAT surface,
Cut a gasket from gasket paper to fit,
Pre glued it to the housing with weather stripping adhesive,
I clamped it to a piece of flat steel with a bar clamp to flatten out the adhesive and remove any spaces or gaps between the gasket and the housing.
I left it clamped over night to completely dry.

Right now the housing on the car isn't leaking, but its the doorman so I'm figuring it will start before long. When it does my plan is to install the housing with the pre-installed gasket and use the weather stripping adhesive to bond it to the head and let it set for 24hours before adding any coolant or running it.

I have pictures of the process, but I don't use any online picture hosting services and I don't see any other way to post pictures here?
(Okay, here is the first time for me to use Photobucket. hope it works.)

The finished project turned out really well, with plenty of sealing surface.






















Mark

[amc49]

.................

[MarkZX3]

Originally Posted by amc49

.................

Well there seems to be some concern about being able to tighten the bolts enough to seal the gasket without cracking the housing.
My thinking is that using a good bonding agent to both sides of the gasket and letting it fully cure should reduce the need for higher torque.

Next, what I found was during the lapping of the housing is they are not "Flat" I had to actually sand beyond the Epoxy fill to get the housing to make a complete and full contact across its entire surface. I figure this is adding to some of the housings getting cracked.

Another thing I found was while lapping the housing was the full length steel inserts were not even with a housing surface, lapping corrected that on at lest the sealing surface side of the housing.

The gasket paper I used was a thin hard pressed type, so my hope is that no more torque will be needed to seal the gasket than the rubber seal. The plan is to create a good cured bond with the yellow weather stripping adhesive and tighten the bolts to normal torque. I do think that running the bolts down "EVEN" with the gasket may be even more important than with the soft rubber seal.

Some people doubt the use of the weather stripping adhesive for a gasket sealer.

The short story of how I started using it.

Around 1977 I had a Chevy Blazer (New) and it had coolant leaks and oil leaks from a number of places. I took it to the dealership several times to get them to fix it, to no avail!. I was a mechanic at the time working for Firestone, so I decided to just fix it myself.
I went to one of the parts stores where we most often ordered parts from and I new all the people that worked ther, and one of them had been around the parts business for YEARS. So I go in getting the stuff I need to fix my leaks and I also ask him for the "Absolute" best gasket sealing on the planet and at any cost?? well he brings out a tube of (at the time) "3M yellow Weather Stripping Adhesive" I ask, this is the best? to which he replied Yep! I have used it ever sense.
It bonds,
It seals,
It don't crack,
It flexes.
It has become my best friend, LoL

Mark

[gary the wolf]

they have complete housings at APS,,l jus had mine changed,,caused by leaking valve cover which l changed a few months ago

[gary the wolf]

all this for a cracked housing,,,mine took a hour to change

[amc49]

The weatherstrip adhesive you have now is not the product you knew and loved in '77. I used to use it quite a bit too, it has been severely changed for VOC content and absolutely does not work as well as it used to. It comes loose now even from rubber, which it is designed to grab the hardest. It lumps up even more than it used to to make uneven thickness. It DOES crack now with temperature.............and it is one of the most inflexible gasket sealers out there, but always was, even back then. Don't know where you got that idea. I don't use it at all for gaskets anymore, way too many other much better products. As flat as you have it now one of the better silicone gasket makers may work well with no paper gasket at all. I'd be trying it with no paper gasket.

No way will a paper gasket seal without crush, the crush is what squeezes the pores of the paper flat to not leak, simply gluing it up seals the sides but not edges, which will eventually seep coolant. The crush also seals gasket from coolant getting in it to soften it to come apart, after all the special chemicals in there it is still paper..........

Using original rubber gasket the cover was never intended to be dead flat, the steel inserts hit first, why they stick up slightly.

The original tightening is closer to inch pounds, if you repeat that the paper gasket will leak.

[MarkZX3]

Originally Posted by gary the wolf

they have complete housings at APS,,l jus had mine changed,,caused by leaking valve cover which l changed a few months ago

Leaking oil isn't what makes these leak, its that stupid slice of inner tube they call a seal!
Its to soft,
Its just flips over,
I'm on my third housing now and I have no doubt its going to leak again. And just to note, none of my housings cracked.

I know a lot of people that have luck with silicone sealants, but I'm not one of them, I did One Time get the RTV black to work a bit.

Also, I found out that the "Great" Permatex #2 formula has been changed from the early version! it used to state "Impervious to Gasoline and Solvents" it doesn't state that anymore and I found out that's its not! I'm not sure if its worth buying anymore or not?

When I got the car it took about a year for the housing to start leaking, when I took it apart it had a crap homemade gasket from what looked like a cereal box. The groove wasn't filled in with anything, but it held up WAY better than the inner tube seal does.

How about the Permatex "High Tack" gasket sealant, its yellow and it states that using this product eliminates the need for weather stripping adhesive, anybody tried it?

Mark