Leaking thermostat housing gasket

[Windsor]

How the **** can I get this thing to stop leaking? I've tried gasket, gasket + RTV, RTV, gasket + copper spray. '68 B383

[birdsandbees]

File both surfaces flat... or look for the crack!

[A383Wing]

the water pump housing is supposed to be flat, the thermostat housing is supposed to have a slight curve to it...the bolt holes are not in line with the center of the housing, so when you tighten the housing down, it pulls the ears so the center of the housing is tight against the water pump housing...do not file the t-stat housing flat...

sounds like it's either cracked or it's lost it's curvature...get a new one

[Windsor]

Both surfaces are flat. Both are new aluminum components. The leak(s) is at the back of the housing and appear to be going through the FelPro gaskets. The coolant starts as droplets around the edge, then drip off. The gaskets (even when sprayed with sealant) are soaked through when I go to replace them.
Never had this much trouble with a thermostat housing gasket.
I'll try to find some rubber or cork gasket tomorrow.

[dual fours]

Check both surfaces with a straight edge. Your sure you have the thermostat in the water pump's groove first with the gasket on top of the thermostat, topped with the neck housing? There are no gouges on the neck housing where the hose fits on from someone cutting off an old hose?
Your sure the water pump housing is not cracked?
Somebody before you might of had the thermostat slip out of the groove and tighten down the neck housing bolts and bent the neck housing.
Are you using original spring wire bands or screw and strap type clamps?


I see some aluminum neck housings have the groove and it's not in the water pump housing, so maybe the t-stat is slipping out before tightening down the bolts?   http://www.ebay.com/bhp/440-water-pump-housing

[Windsor]

Both are new components. The recess for the thermostat is in the housing, not the waterpump. Waterpump flange is smooth.

[A383Wing]

Both surfaces are flat. Both are new aluminum components.

and there is your problem...I have never heard of anyone getting the aluminum t-stat housing to seal properly....toss the aluminum housing and get a stock one, your problem will be solved

[dual fours]

Both surfaces are flat. Both are new aluminum components.

and there is your problem...I have never heard of anyone getting the aluminum t-stat housing to seal properly....toss the aluminum housing and get a stock one, your problem will be solved

A383, are you saying to get rid of the aluminum T-stat housing and the aluminum water pump housing?

If not both, then neither the stock stamped steel  T-stat neck housing or the aluminum water pump housing will have the groove for the T-stat!
  http://www.ebay.com/bhp/440-water-pump-housing

[Mopar Nut]

How the **** can I get this thing to stop leaking? I've tried gasket, gasket + RTV, RTV, gasket + copper spray. '68 B383

You can buy a thermostat housings with "O" rings, or stainless steel thermostat housings on eBay. I bought my aluminum thermostat housing with a 3/8 flange from Mancini Racing never had a problem.

Can you post a picture of yours?

[Windsor]

Let me clarify, water pump housing is smooth with no recess. Water neck/thermostat housing has a recess for the thermostat, but the flange is flat without a curve. Thermostat (when installed) is level with the flange.
Don't have picture of it right now, but it is this one. http://m.ebay.com/itm/400753566922

[Mopar Nut]

That looks like the same one I have from Mancini Racing.

What brand of gasket did you use?  I used Fel-Pro.

[Windsor]

I guess I'll get another thermostat housing. If it keeps doing it, I'll just weld the dang housing on and use one of my inline thermostats.

[Windsor]

I used FelPro, black paper type gasket. Every time I pulled it back off, the gasket was saturated.

[Mopar Nut]

This is the Fel-Pro #35063 I used, never seen a black Fel-Pro thermostat gasket.

http://www.felpro-only.com/blog/side/

[Windsor]

I'll have to order some online if I can't find some tomorrow.  Local store have the black ones. I'll see what the stores have in portland tomorrow after my surgery.

[1974dodgecharger]

I used the same one you have and NO leaks, but I used a different gasket.  like those posted felpro...I believe.

I had the chrome one and leaks galore....

[werner]

I HAD A MP CHROME WATER NECK ON MY HEMI THAT I TRIED TO STOP FROM LEAKING. TRIED EVERTHING FROM SANDING ON PIECE OF GLASS ETC TO TRY AND GET FLAT. TRIED EVERY KIND OF GASKET MATERIAL AND DOPE. NOTHING LATSED LONGER THAN 3 MONTHS.

THREW WATER NECK AWAY AS PER DIRECTION FROM A MEMBER ON HERE AND BOUGHT A BILLET ONE WITH "O"RING AND HAVENT TOUCHED  IT IN 3 YEARS.

[Ghoste]

Exactly my experience too werner.  (although I haven't hit the three year mark yet)

[68 RT]

Both surfaces are flat. Both are new aluminum components.

and there is your problem...I have never heard of anyone getting the aluminum t-stat housing to seal properly....toss the aluminum housing and get a stock one, your problem will be solved

I agree with that, the stock ones work best!

[John_Kunkel]

I've tried gasket, gasket + RTV, RTV,

Are you using a glycol-resistant RTV? Are you allowing the RTV to set before refilling the system?

http://www.permatex.com/products-2/product-categories/gasketing/gasket-makers/permatex-water-pump-thermostat-rtv-silicone-gasket-detail

[A383Wing]

Both surfaces are flat. Both are new aluminum components.

and there is your problem...I have never heard of anyone getting the aluminum t-stat housing to seal properly....toss the aluminum housing and get a stock one, your problem will be solved

A383, are you saying to get rid of the aluminum T-stat housing and the aluminum water pump housing?

If not both, then neither the stock stamped steel  T-stat neck housing or the aluminum water pump housing will have the groove for the T-stat!
  http://www.ebay.com/bhp/440-water-pump-housing

No, I'm saying ditch the t-stat housing that the hose clamps onto...just get a stock steel or cast housing

[Windsor]

A383Wing, does a stock housing have a recess for the thermostat? Or was the stock thermostat in a recess in the water pump?
Got some blue ones, I'll try it out. I'm down for the count for a day or two. I'll let y'all know if it seals or leaks.
Napa couldn't give me info on a stock housing, but I will order one if I can't get this one to work.

[Dino]

I run this one from O'Reillys.  Never had any issues with it, price is right as well!

http://www.oreillyauto.com/site/c/detail/MRY0/84830/01397.oap?year=1969&make=Dodge&model=Charger&vi=1078961&ck=Search_01397_1078961_3329&pt=01397&ppt=C0331

[Windsor]

The winning combo was the blue FelPro gasket and the copper spray. Sprayed flanges and gasket (both sides), 15 minute wait to breath off the propellant, 1 day to set with bolt heads just touching the housing, torqued and waited 1 day before adding coolant.
No more coolant leak (for now).

[Mopar Nut]

Good, I would recheck the bolts after some run time.

[1974dodgecharger]

The winning combo was the blue FelPro gasket and the copper spray. Sprayed flanges and gasket (both sides), 15 minute wait to breath off the propellant, 1 day to set with bolt heads just touching the housing, torqued and waited 1 day before adding coolant.
No more coolant leak (for now).

still using chrome head?  It be back after one week.....

[Windsor]

No chrome. Aluminum housing held down with ARP black 12pt bolts. I hate chrome, valve covers are always pissing me off when I see them.

[myk]

Agreed...