Odd coolant leak!

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doogievlg

doogievlg

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I put some coolant in my motor on Sunday getting ready to fire it up for the first time. I noticed a leak where the hose goes into the thermostat housing. I cranked down on it has hard as I could and it kept leaking. Took the hose off and replaced it thinking there may be a cut but the new hose did the same thing. I'm not a big fan of leaks ecspecially on a brand new motor. Any advice is welcome!
 
Are you sure its not coming from the housing itself? It is a VERY common leak on small block mopars. I've had a ton of problems getting mine to seal also.
 
First of all, I only run straight water until the engine is broken in and I know there are no leaks. Water is much easier to clean up.

Second, where is it leaking? Between the hose and the thermostat housing, or between the thermostat housing and the intake?

I use the stock spring clamps on my Challenger. I put a thin layer of weatherstrip adhesive on the inside of the hose before installation. Make sure there isn't a crack in the housing that's covered by the hose...but below the clamp.
 
Use RTV without a gasket and only mess with it once.
I change my thermostat a couple of times a year and do it this way (NEVER EVER leaked a drop)

1/8 bead of RTV, put it on before it skins over, tighten it down and wipe of any that squeezed out.
Done deal, and I'll even start the car and drive it as soon as it's back together.
I don't understand when I see people on here all the time fighting that leak when it is so simple to not have it happen.
If it's the hose or neck, same thing (a thin film of RTV smeared on the inside of the hose and bone dry for good.)
 
Leak is coming from where hose meets the housing. Not where the housing meets the intake.
 
I saw that but the other replies seemed to be misguided.
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How so? I said I put a layer of weatherstrip adhesive on the hose before installing the clamp. It works the same way as the RTV that was mentioned. Also, I said check for a crack in the housing.
 
I would suspect the housing is cracked if you replaced the hose and it still leaks. As they say, housing leaks are common, but at the base. If it's not there, suspect the housing neck is cracked.
 
How about a picture of what you are working with?

What kind of clamp are you using?

Where are you positioning the clamp?

there could be porosity in your housing.

is it a chrome housing?

Pictures can help get more answers.
 
I had a chrome housing corrode from the inside. Only had a pinhole on the outside. Thought it was the hose. Something to check.
 
I had a similar leak when I put in my Aluminum 3 core radiator. It was on the bottom hose. Previous owner used a larger worm type clamp and cranked it all the way down. Well the clamp wasn't round at that point and it was making the hose flex enough where coolant was coming past the barb under pressure. It was dribbling a lot. As soon as I took the clamp off (without the engine running) the leak stopped because the hose went back to round. I found the correct clamp in the trunk and put it on, hasn't leaked a drop since.

Check to make sure the hose clamp is the right size and still holds the hose circular. OR find the appropriate "T bolt" clamp. They actually hold more pressure when sized properly.
 
I had a similar problem when using a chromed aftermarket thermostat housing on my SB. It was impossible to get it not to leak. Went back to the stock cast iron piece and have not had a problem since.
 
nerd racing said:
i had a similar leak when i put in my aluminum 3 core radiator. It was on the bottom hose. Previous owner used a larger worm type clamp and cranked it all the way down. Well the clamp wasn't round at that point and it was making the hose flex enough where coolant was coming past the barb under pressure. It was dribbling a lot. As soon as i took the clamp off (without the engine running) the leak stopped because the hose went back to round. I found the correct clamp in the trunk and put it on, hasn't leaked a drop since.

Check to make sure the hose clamp is the right size and still holds the hose circular. Or find the appropriate "t bolt" clamp. They actually hold more pressure when sized properly.
Click to expand...
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