1957 leaking coolant at the rear of the engine

[TJShea]

Hello. I am still a novice when it comes to these cars, hence my pretty "basic" questions. I parked and noticed a pretty good coolant leak pooling about mid center of the car at the rear of the engine. I checked the heater and there is nothing that indicated that is leaking. I was told during some previous work I had done about 1 year ago that the core was pretty new. I have not been using the heater. Anyway, I checked carpets, etc and no indication of a leak there. It is a pretty good pooling, I do not see any hoses the obviously would have coolant flowing through them anywhere near that area. Looking over the rear of the engine as best I can from the top rear, I could see what appears to be coolant caught in small pools around the rear. it appears that there is coolant around a cover that is on the top of the engine between the heads. Could coolant be flowing below this cover, and because the gaskets have gotten bad, be leaking from there? And if so, does this indicate a much worse problem than just a bad gasket from this cover? I looks to be quite a process to get to this cover that would require removing the intake manifold and all that goes with that. Thanks in advance for any info help.

 

[biddle]

On future posts, use the four-digit model year in your subject as prompted. I updated it.

 

[74 Harley]

Can you post a picture? I think you are referring to the valley cover, and that doesn't hold coolant. You may have a leak between the head and manifold.

 

[TJShea]

Can you post a picture? I think you are referring to the valley cover, and that doesn't hold coolant. You may have a leak between the head and manifold.

I cannot post a photo. The car is now at another location parked in a storage garage (Not enough garage space at the house). The cover I referred to is called the "valley plate" I just found it in a schematic in a parts catalog. It does require a gasket. So I would suppose a "leak" coming through there would be because of a head gasket leak.

 

[Ward 57]

There is no coolant running under the valley pan so that can't be the source. A leaking head gasket would just run down along side & back. Plus you would be able to see the exhaust dripping coolant and would be able to smell it in the exhaust.
I vote for the intake manifold gasket. Not uncommon.

 

[TJShea]

There is no coolant running under the valley pan so that can't be the source. A leaking head gasket would just run down along side & back. Plus you would be able to see the exhaust dripping coolant and would be able to smell it in the exhaust.
I vote for the intake manifold gasket. Not uncommon.

Thank you. It is big help to know that there is no coolant flowing under that valley cover. I do not have coolant leaking out of the exhaust. I do have some condensation when I first do a cold start up, but that quickly dissipates and does not reoccur after the engine has been warmed up and restated. I do not smell or see anything dripping out after it warms up. A leaking intake manifold looks to be most likely based on your info and also looks to be a much easier fix than the head) gasket(s). At least to my novice eyes. A trip to a local car restoration/repair facility will be in order. My tackling this is just not in my skill area, and if the problem is bigger, they are the guys to solve it. Thanks again for the info. This forum and the folks on it have been a great help. I find so much good info here and have done a number of things and preventative maintenance interventions from what I have read here.

 

[Ward 57]

Thank you. It is big help to know that there is no coolant flowing under that valley cover. I do not have coolant leaking out of the exhaust. I do have some condensation when I first do a cold start up, but that quickly dissipates and does not reoccur after the engine has been warmed up and restated. I do not smell or see anything dripping out after it warms up. A leaking intake manifold looks to be most likely based on your info and also looks to be a much easier fix than the head) gasket(s). At least to my novice eyes. A trip to a local car restoration/repair facility will be in order. My tackling this is just not in my skill area, and if the problem is bigger, they are the guys to solve it. Thanks again for the info. This forum and the folks on it have been a great help. I find so much good info here and have done a number of things and preventative maintenance interventions from what I have read here.

Good luck. It's not a big job if you have done it before and you said your mechanical skills are lacking. A shop could verify and do in a day, while you would be learning on the job by yourself and a not so explicit shop manual.

 

[CtCarGuy]

I had the same problem with my '56. It turned out to be the heater control valve in the front of the engine. It took a long time to find but the coolant traveled down the valley pan and onto the bell housing. The valve was leaking where is screwed into the manifold and would only leak when under pressure. Hope this helps.

 

[Ward 57]

I had the same problem with my '56. It turned out to be the heater control valve in the front of the engine. It took a long time to find but the coolant traveled down the valley pan and onto the bell housing. The valve was leaking where is screwed into the manifold and would only leak when under pressure. Hope this helps.

Now that's a new one to me. How did you find it? Good sleuthing stories are always appreciated.

 

[CtCarGuy]

Now that's a new one to me. How did you find it? Good sleuthing stories are always appreciated.

We had the engine running without the air cleaner and used a strong light to spot wet areas. The key was seeing coolant on the bell housing knowing that there was no coolant located in that area of the engine. We first thought heater core but looking under the car we could tell it was not from there. Good luck. I hope you find the problem.

 

[55blacktie]

How is the car running? If the leak is coming from an intake manifold gasket, you could have a vacuum leak as well. Could the leak be coming from a freeze plug?

 

[TJShea]

How is the car running? If the leak is coming from an intake manifold gasket, you could have a vacuum leak as well. Could the leak be coming from a freeze plug?

The car is running just fine. I was thinking that if there was an intake manifold leak I would expect some leaking into the intake and there would be coolant burning in the cylinder(s), but I do not see anything that would indicate that. I do not have anything occurring that is noticeable, other than the puddling of coolant under the car at the rear of the engine, and wetness on some areas at the upper rear of the engine, like below the distributor, and some wetness at the rear of the valley pan that I thought was some slight oozing oil but now I believe to be coolant. It is a pretty good flow and will leave about a dinner-plate sized puddle in about 5 minutes after I turn the car off. There is one thing that I did do last week that I just recalled. I briefly turned the heater on and cycled the heater controls just to see if everything was working. Before that there was no leak. After turning it off, I later found the coolant pooling under the car. It is still doing that a week later, but only after it is run. There is no leaking around the heater or hoses, nor any wetness in the carpeting inside the cockpit. Perhaps it does have something do do with the heater control valve, although there is no leaking that I could see at the front of the engine. As for freeze plugs, I thought they were low on the block and would not leave coolant just below the distributor Thanks for all of the info and ideas. I think it is time for greater minds and abilities than mine to take a look, It will take a trip to a local restoration/repair shop as soon as they have room.

 

[TJShea]

We had the engine running without the air cleaner and used a strong light to spot wet areas. The key was seeing coolant on the bell housing knowing that there was no coolant located in that area of the engine. We first thought heater core but looking under the car we could tell it was not from there. Good luck. I hope you find the problem.

The heater control valve sure looks like a possibility. Changing that control valve sure would be preferable than the intake manifold gaskets. It is a stumper for me, but again I am nowhere as skilled as I see many of the folks here are when it comes to these vehicles. I am going to get it into a local restoration/repair shop and they can take a crack at this, I have a couple more things that need a bit of professional work above my skill set, so just another thing to add to the list, and further drain the wallet. But that is kinda the things one gets when having the fun associated with these fine older cars. and the great folks at the car shows, Even the occasional frustrations are worth it.

 

[jimntempe]

The heater control valve sure looks like a possibility. Changing that control valve sure would be preferable than the intake manifold gaskets. It is a stumper for me, but again I am nowhere as skilled as I see many of the folks here are when it comes to these vehicles. I am going to get it into a local restoration/repair shop and they can take a crack at this, I have a couple more things that need a bit of professional work above my skill set, so just another thing to add to the list, and further drain the wallet. But that is kinda the things one gets when having the fun associated with these fine older cars. and the great folks at the car shows, Even the occasional frustrations are worth it.

I had a very similar leak on an 86 caprice. The heater water flow control valve on the engine would leak when the car was shut off but you mostly saw the drain off and not the leak at the valve. Probably leaked while running but the heat made the water evaporate quickly. I think you're on the right track with the idea of replacing that valve, esp since your problem started with the use of the heater controls.

 

[Ward 57]

A simple pressure test on the cooling system should help you find the leak when it is cold. The system is still under pressure after shut down forcing the coolant out. When cold you can root around without burning yourself. A simple pump that replaces the radiator cap would do the trick if you want to investigate it further yourself But your shop should be able to find it pretty quickly.
A leaking intake gasket would not suck coolant into the engine just leak over the top.

 

[sylvurhfox]

A simple pressure test on the cooling system should help you find the leak when it is cold. The system is still under pressure after shut down forcing the coolant out. When cold you can root around without burning yourself. A simple pump that replaces the radiator cap would do the trick if you want to investigate it further yourself But your shop should be able to find it pretty quickly.
A leaking intake gasket would not suck coolant into the engine just leak over the top.

I recently had a similar incident. I found the thermostat housing was leaking around where it attaches to the manifold. The coolant would drip onto the valley cover and run to the rear of the eng and go over the lip of the valley cover. Check the thermostat housing for pin holes also, they rust over time if there was just water in the eng.

 

[TJShea]

I recently had a similar incident. I found the thermostat housing was leaking around where it attaches to the manifold. The coolant would drip onto the valley cover and run to the rear of the eng and go over the lip of the valley cover. Check the thermostat housing for pin holes also, they rust over time if there was just water in the eng.

Thank you. I'll have that checked too. Great info on this site.

 

[knuckle47]

Good Luck TJ…. When you get this solved, report back on what you had to do to fix it.

 

[TJShea]

A little update. And again thank you all. CtCarGuy you may have hit the nail on the head. I was able to get the car out in bright sunlight and let it idle and warm up etc. I soaked up all the coolant/wetness I could see at the rear of the valley plate, and some puddled just above the right side of the bell housing below the distributor. I then started at the front of the engine and immediately saw a flow of coolant coming out of the threads of the heater control valve, and running down to the front of the valley plate. I had to look hard to see it, as it was just a slightly different color from the engine color plus I found a loose hose clamp on a small hose just below the valve.
I could see a small amount of puddling starting under the car at the below the bell housing. I wrapped a bundle of paper towels around the base of the valve ( I also tried to tighten it with a wrench but it was "tight"}. I soaked up any coolant I could see at the rear of the engine at or below the valley plate. I let the car idle for another 15 minutes. No coolant dripped, nothing puddled at the rear of the engine, and the paper towels were pretty soaked, enough that the heavy bundle could be wrung out. I have ordered a new valve, and will install it with plumbers thread seal/tape and see what I get. Hopefully you all diagnosed the problem and no expensive trip to the restorers shop (at least for now 😀). After I change the valve it will get a road test by taking it to the AACA show this coming weekend. Freeway speeds should increase the coolant pressure in the system and I'll see what happens. If lucky, you all fixed my issue. Hopefully the next one will be this easy. This is a great forum and information resource!

 

[Ken Carr]

A little update. And again thank you all. CtCarGuy you may have hit the nail on the head. I was able to get the car out in bright sunlight and let it idle and warm up etc. I soaked up all the coolant/wetness I could see at the rear of the valley plate, and some puddled just above the right side of the bell housing below the distributor. I then started at the front of the engine and immediately saw a flow of coolant coming out of the threads of the heater control valve, and running down to the front of the valley plate. I had to look hard to see it, as it was just a slightly different color from the engine color plus I found a loose hose clamp on a small hose just below the valve.
I could see a small amount of puddling starting under the car at the below the bell housing. I wrapped a bundle of paper towels around the base of the valve ( I also tried to tighten it with a wrench but it was "tight"}. I soaked up any coolant I could see at the rear of the engine at or below the valley plate. I let the car idle for another 15 minutes. No coolant dripped, nothing puddled at the rear of the engine, and the paper towels were pretty soaked, enough that the heavy bundle could be wrung out. I have ordered a new valve, and will install it with plumbers thread seal/tape and see what I get. Hopefully you all diagnosed the problem and no expensive trip to the restorers shop (at least for now 😀). After I change the valve it will get a road test by taking it to the AACA show this coming weekend. Freeway speeds should increase the coolant pressure in the system and I'll see what happens. If lucky, you all fixed my issue. Hopefully the next one will be this easy. This is a great forum and information resource!

Congratulations...way to go...Loved your last sentence!