My '65 GT housing has left a little puddle on the water pump every year for close to 20 now. Never overheats, never leaks when I drive it, holds pressure when tested, but always has the little puddle. I tried new gaskets a few times, finally just figured the puddle was supposed to be there for some reason... lol

You may want to check that your housing isn't warped- using a straight edge to check it and the intake both. Some say gasket and no sealant- I've always put a light bead of rtv on both sides, and other then Red- always seems to seal.

 

I tried new gaskets a few times, finally just figured the puddle was supposed to be there for some reason... lol

You may want to check that your housing isn't warped- using a straight edge to check it and the intake both. Some say gasket and no sealant- I've always put a light bead of rtv on both sides, and other then Red- always seems to seal.

Lol, yeah I’ve had that “puddle is supposed to be there” thought for a long time too. I decided to battle it, but I’m losing.

I did check the housing and ran it over a sheet of sand paper on a flat surface to sort of shade tree plane it. Seemed flat enough.

 

Put a thin bead of rtv gasket maker on both sides of the gasket.

 

Nope, no chrome here. I've heard horror stories before, so this is the factory part.



Yeah, that's the way I'm doing it.

 

not the chrome housing is it? I could never get the chrome to not leak so I replaced it with the aluminum.

 

I was just going to say the same thing about the chrome housing. If that's it, ditch it and get a plain stock looking one from the auto parts store.

 

Same as everyone else, I had a chrome one and no matter what I did I couldn't stop the leak. Tons of sealant, little sealant, o-ring, etc. and it never stopped. Got pissed and bought a stock cast style and just painted it black and it's never leaked and has been off several times and back on.

 

I am running one of those Scott Drake aluminum housings on my Performer RPM, never had a leak. Using a bit of RTV on both sides of the gasket.

 

Same here. I am using one without any sealant. Without issues as well.

 

I find that if you set the thermostat in place, and RTV the gasket on, give it a few minutes to set up, then RTV the other side and bolt it on. I use either the grey or black RTV.

 

Try a thin smear of Ultra Grey RTV on both sides of the gasket. Just that a bit comes out on the sides when you torque the bolts. Surface must be clean down to the metal and not wrapped.
Good luck!

 

I fought the same issue and finally got it stop using Edelbrock Gasgacinch on the intake side and a thin film of RTV on the water neck.

 

Interesting, thanks for the suggestions y’all!

 

I also put a dab of blue(medium) thread lock on the bolts. Ive had a couple back out over the years and it always helps keep the corrosion down to a minimum!

 

If you've been here a while you probably have noticed I tell people to spray foot powder or some such other talc around a leaking area that's driving you crazy. In particular that timing cover puddle. It would be the first time someone declared war on the thermostat and all the time it was the driver's side front water port at the intake sneakily dripping. Or even leaking IP out of the timing cover, kind of a rare leak, but I've had it. Just want you to be SURE you're positive of the leak source.

 

Gasketcinch. Apply some to both sides of gasket and both mating surfaces. Let it set up, then put the gasket on and bolt down the housing. If the drip is on the passenger side of timing cover, check the bolts. At least one of those pass through a coolant.

 

I'm with Gypsy on this one...unless I see a leak of green fluid dripping out of something, I've learned not to assume I know where the coolant is exiting the engine.

Rather than the powder trick though, I rely on a mity-vac tester that lets me put about 10 to 14 PSI on the engine cold. So much easier to find leaks when you can really get your face in there without worrying about getting burned.

Bought mine off amazon for about $25 or $30 and it came with several different radiator cap adaptors. I've used it on multiple mustangs and my kid's Subaru and I've found every leak I've hunted. Most of the time it wasn't coming from my first suspect.

Phil

 

Two things I found that seems to work:

1. Make sure the thermostat stays in its little "seat" inside the housing. It's hard to get it to stay located when you put the face up to the intake. Sometimes it looks properly seated when it's not.
2. The blue fel-pro gasket works really well. The grey fiber gaskets are garbage. If you haven't tried the blue, try that before you put RTV on it.

Good luck!

 

I just smear both sides of the 5.0 housing with RTV (like, a thin smear) smack it on, tighten it up with a wrench. Just did one last week.

 

Yeah, that’s not doing it in this case.

 

Snott Drake and blue RTV, the housing on my 65 doesnt leak a drop.

 

I had one that was porous, second one was ok.

 

No tips, but if you’ve checked everything per Gypsy et al and sealed as the others have suggested, pretty much leaves one or both surfaces not being flat...

 

good point about the bolts bottoming out could be rtv or something else in the bottom of the holes.
leave out the thermostat and gasket just bolt up the housing to the manifold. Does it get tight or is it still still loose.
also as Gypsy said it could be leaking from another spot

ken

 

I prefer permatex form a gasket #2 put some on both sides of a paper gasket it wont squeeze out the gasket.

 

I've seen intake leaks look like T stat housing leaks

 

I'm afraid after 24 years, I'd freak if I opened the hood and the puddle was missing, probably think I ran it out of coolant. I've kinda got used to it, like the leaky power steering hose, its just my car marking its territory...

I have learned to stop using RTV on gaskets, its not a gasket sealant, its for making gaskets. It never sealed that leak, nor did it ever give me a clean oil pan seal. I've moved on to permatex or gaskacinch however its spelled. I can remember as a kid seeing that happy 40s blond with a nice rack & bare legs in the air smiling away at me with the oil pan gasket in her hand. My dad's favorite sealant. I've strayed away for a few decades but I'm back, and she is still looking good. Remember when you could find playboys in every mechanic's bathroom - the one the mechanics used that is - I digress - again...

 

Not sure if you are still searching for your leak but if it is pooling on the driver's side the thermostat housing is most likely not the culprit. You should be looking at the intake and the timing cover as the source for your leak. Good luck with your search.

 

Yeah, the search continues and I bet you’re right. I intend to pull the engine and reseal everything, but that’s going to have to wait until I get my daughter’s 66 done. Until then, it’s just going to have to mark it’s territory a little.

 

According to your first post, you said driver’s side.

I would suggest checking all of your timing cover bolts and the water pump bolts.

After winter this year and spring thaw in a garage, while working on steering and suspension my cooling system started seeping and progressively worse. I found several bolts that were slightly loose...not finger loose, just enough to leak on my 5.0.

The only leak pooled on drivers side pocket. After tightening, ran it up to operating temp and shut off.

I wasn’t exactly sure if it was coming from top or from below. I cleaned it up and crammed a wad of paper towel in socket to see if it was the head/manifold or water pump. The fan will spray it all over the place.
In my case, the bottom of paper towel was wet and dry on top.

Just don’t go crazy on it.

 

You can use the "foot powder spray" same as you might for oil leaks. Clean and dry everything then spray everything in the area. Do whatever makes it leak a little and then you should have a super obvious trail back to the source. The fan won't blow it off appreciably. I've had Cruex spray stick to the exterior of a motorcycle engine at 150 mph. Leftover powder washes right off with plain water.

 

You can use the "foot powder spray" same as you might for oil leaks. Clean and dry everything then spray everything in the area. Do whatever makes it leak a little and then you should have a super obvious trail back to the source. The fan won't blow it off appreciably. I've had Cruex spray stick to the exterior of a motorcycle engine at 150 mph I Leftover powder washes right off with plain water.

Worlds fastest Gypsy!