Intermittant coolant leak??

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Fredb_

Fredb_

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Sounds odd, I know. I noticed the smell of antifreeze recently. Checked coolant level and was low. I added water to see what I might find and noticed a pretty good leak off the front of the pan, but couldn't see exactly where it was coming from. I pulled it outside and filled with fluid while running the engine. Got it up to temp and shut it off to let it dry out a little. After cooling down fluid level stayed full. I started it a ran it two or three times up to temperature and then shut down. I had no leaks until about the fourth or fifth time when I got a good amount of water running out the front again. Can't tell where it's coming from but looks somewhere in the area of water pump. Ideas?? Thanks.
 
Fredb_ said:
Can't tell where it's coming from but looks somewhere in the area of water pump. Ideas?? Thanks.
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Yup. Probably coming out of the weep hole under the shaft. Place your finger under the shaft area and you will feel a hole.

If it is coming out of that hole, time to replace the pump.
 
Fredb_ said:
So it can leak "sometimes"? Thanks.
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When the seal is in the process of failing.....yes. If it is coming from there, it won't get better.

BTW the top bolt towards the driver's side goes into the water jacket, so if it is loose or not well sealed, that can leak.

What year of /6 and car is this? If the system does not have an overflow tank, then overfilling the radiator will result in coolant blown out. The excess coolant when it gets hot and expands will blow out the overflow tube. If it does this, it can end up on the engine front if the overflow hose does not reach down below the bottom of the radiator. A cooling system with no expansion tank should be filled to about 1-1/4" below the lip of the radiator cap opening on the radiator, no higher.
 
225 Slant from a 1976 Duster running in a 49 Dodge Roadster. Does have overflow tank that mounts to firewall (right side) and drains down and back.
 
Do you have a mechanic's mirror? Proper automotive diagnosis really mandates one. They are cheap. Get one. Confirm the leak and repair.

Sounds like the water pump.
 
Checked it again, had to start and stop the engine a few times before the leak started again. Almost seems to be related to the opening of the thermostat. Anyway the water is NOT coming from the hole on the bottom of the housing where the shaft runs. Using a light and mirror it appears to be coming from just below or behind the upper right water outlet on the water pump. It does not appear to be the hose and I tightened the bolts too. Water was running out in a small stream.
 
A cooling system pressure tester would certainly help. The big box parts stores will rent you one and return your money when you return the tool if you don't have one.

The only other nipples on the water pump would be the bypass and one heater hose. Sounds like one of those is leaking at the hose connection, or cracked.
 
I had a thermostat housing leak like that one time. Tried tightening the hose clamp but it didn't help.

I ended up removing the housing and sanding it where the hose attaches. It took care of the leak. Replaced the t-stat while I was there.
 
Lots of times the hoses get a crusty buildup where they mate to the inlets and outlets where they clamp. Once they do that, they are almost impossible to stop leaking. The hoses on my truck are like that now. I need to replace them.
 
This motor only has about 9K on a fresh rebuild. The water pump looks really good as do the hoses. I hope it isn't something more serious, but not sure what that would be. Will get the pump after the 4th. Happy Independence Day to all!
 
After looking a bit also look at the junction of the head and block behind that area to see if it coming out of the head gasket. Hopefully not, and that's not the most common of issues by any means; it is the last thing I can think of in that area. Do you know if the head bolts re-torqued after few 10's of miles after the rebuild?
 
I had the little 5/8" hose that goes from behind the water pump to the head leak. That was my 1969 Dart 225 in college, and I was a dumb kid. Took me over an hour to work a new hose on. I replaced the one in my 1964 Valiant w/ silicone heater hose, so I will hopefully never repeat that effort. It is much more flexible so easier to work on, and should last forever.
 
I'm suspecting the bolt that penetrates into the water jacket. All the bolts felt fairly loose and none seemed to have a good sealer applied to the threads. Any suggestions on what to use on the bolt threads? I'm kinda "old school" permatex type guy, buy I know there's probably more products available for the application.
 
High temp Permatex is fine. It's good stuff.
 
I have several slant cars I;ve been piecing together. 3 engines, 3 leaking thermostat housing!!! it would be just a pinhole. they were alum, and it deteriorates over 50 years. I got some from Rock for just a few $$, NOt aluminum!!!! fixed it all.
 
Good news I think. Replaced water pump and hoses, but I think it was just the bolt that penetrates the water jacket. Leak seems to be fixed. This slant six install in the 49 Dodge is pretty clean, and I'm glad it is running an electric fan on the front side of the radiator. It made the water pump install easier. I could see where that pump could be a bit of a bear if room was tight.
 

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LOL that's purdy neato, Fred.
 
Thanks. I didn't build it, but bought it from a guy who lives a few hours from me. I also own a stock 38 Ford Sedan complete with flathead V8 and mechanical brakes. I was looking for something vintage but updated when I found the Dodge. It's got 76 Duster suspension and drive-train. It's a pretty cool ride. I'm liking the slant six so far. Good gas mileage with enough power make it feel sporty.
 
And it is red on the inside and the outside! Purty nice looking car. The triple (stromberg?) carbs are pretty neat.
 
I use "Gasket Sealant" on such bolt threads. It stays flexible, and is very sticky. You can remove it with ethanol.

That slant will surely turn heads when you pop the hood at a car show. But no need to slant the engine under that tall hood. I bet a Magnum V-8 with its beer keg intake would easily fit.
 
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