how to identify leak in exhaust manifold?

[akintosyali]

My Port side chrysler 426 gas engine is having a major issue:
Cylinder #7, (SB side of the P engine, furthest one back, which sits lowest) has water squirting out when I run or crank or run the engine.
I don't see few drops, it is more like 3-5 table spoons each time the piston goes up.
I see three possibilities:
a-risers: inner wall of one of the elbows of the riser is cracked or the seal between the parts have gone bad
b-exhaust manifold: there is a crack in the exhaust manifold.
c-the engine block is cracked.

I shut off the seacock and did a compression test, all cylinders on this side of the engine has 120-130 lb compression. Not great, but not too shabby either. I hope it is not a cracked block!

How can I test the exhaust manifold or the risers to see if there is a crack in the inner pipe or if one of the joints have a bad seal?

I am assuming the there is a systematic way to test things and isolate it, I just don't know where to start.

Thanks,
Akin

 

[akintosyali]

My initial thought is to take the manifold off the block (with raisers attached),
run the engine without the exhaust manifold to see if there is a crack in the engine. If the block is good, continue:

test the manifold by filling the water jacket with water and see if there is a leak
then fill the raisers with water to see if there is a leak

thoughts?

 

[rustybucket]

Is your exhaust manifold and/or raw water cooled? If so, how old is it? If more than 5 or 6 years old, it's past due for replacement. Go ahead and do both engines if so.

If one, or both are raw water cooled and more than 6yrs old it's past due for replacement.

 

[akintosyali]

Both engines are raw water-cooled. (no heat exchanger, no antifreeze running through my engines)
The boat is in freshwater. I had the boat for 13 years, didn't replace any riser nor the exhaust manifold while I owned the boat.

My issue is, if the engine block is cracked, there is no reason to replace the risers as I doubt I can find a rebuilt 426 Chrysler engine and would have to repower.

 

[rustybucket]

Both engines are raw water-cooled. (no heat exchanger, no antifreeze running through my engines)
The boat is in freshwater. I had the boat for 13 years, didn't replace any riser nor the exhaust manifold while I owned the boat.

My issue is, if the engine block is cracked, there is no reason to replace the risers as I doubt I can find a rebuilt 426 Chrysler engine and would have to repower.

I'd pull the manifolds off with intentions of replacing. They do last longer in freshwater but 13+ years is asking a LOT. At least that would give you a good look at the block.

There is no way for you to get a video camera (phone) or a borescope cam back in there to determine where the water is coming from? My guess is the joint/mating surface between the manifold and riser. The cast iron is probably just one flake away from REALLY leaking.

 

[bigbill]

that sounds like a pretty big leak, i'll bet you can see where it is coming from with a mirror or cell phone camera. i f you pull the manifold the and it is bad i'm sure you will be able to see it. like i said, that is a pretty bad leak

 

[akintosyali]

i have been thinking about it, and I have an additional idea:

on the exhaust manifold, unhook the hoses, place some clear hoses, fill it with water. See if the water level is going down.

On the risers, remove the lower hose, place a clear hose and fill it up. Water level should level off at the top point of the upper elbow and stay there. If there is a crack, the water in the clear hose will eventually drop to the level of the crack.

I am just noting here in case someone runs into a similar problem.

 

[akintosyali]

The issue has been identified without taking any manifold pieces apart:
1-I blocked the engine water intake with a plug, removed the thermostat, filled it with water, and water stayed level.
2-I removed the hose on the lower exhaust elbow, filled it with water, and the water stayed level.
3-I plugged the discharge outlet of the exhaust manifold, and used a clear hose to add water to it. I could see that the water level started to go down, about 1/8 every 2-3 seconds. When I blew into the hose, the discharge rate increased.

Now that I identified the issue, I will replace the right part. Again, posting this process so that if anyone else is in the situation, my experience and process will help them identify the actual cause.

 

[rustybucket]

The issue has been identified without taking any manifold pieces apart:
1-I blocked the engine water intake with a plug, removed the thermostat, filled it with water, and water stayed level.
2-I removed the hose on the lower exhaust elbow, filled it with water, and the water stayed level.
3-I plugged the discharge outlet of the exhaust manifold, and used a clear hose to add water to it. I could see that the water level started to go down, about 1/8 every 2-3 seconds. When I blew into the hose, the discharge rate increased.

Now that I identified the issue, I will replace the right part. Again, posting this process so that if anyone else is in the situation, my experience and process will help them identify the actual cause.

So I'm a little confused, which part do you think is faulty? Be cautious pouring water in there, if an internal crack exists you could potentially fill a cylinder up with water.

 

[dsharp]

It sounds like the elbow is cracked. Barr still makes replacement manifolds and elbows. If you replace the manifold don’t forget that there is a copper tube in the manifold that takes water from the back of the manifold to the front of the manifold

 

[akintosyali]

It sounds like the elbow is cracked. Barr still makes replacement manifolds and elbows. If you replace the manifold don’t forget that there is a copper tube in the manifold that takes water from the back of the manifold to the front of the manifold

I pulled the manifold off. There is no copper tube inside the manifold? I have water coming in to the manifold from the aft side of the manifold, lower end hose connection and then it comes out of the fore end of the manifold, top side hose connection, which leads to the upper exhaust elbow.

 

[Dustcutter88]

Remove and take to radiator shop. They can plug all ports and pressure test under water to look for leaks.

Ron