1992 5.7 engine leaking water into cylinder

[lutzinmn]

I have a 1992 5.7 engine. I was replacing plugs and noticed #3 and #1 cylinders had water in it. I had the head taken off and checked. No issues with the head or its gasket. I a not seeing any visible cracks on the exhaust manifold. Anyone have ideas how the water is getting in?

 

[alldodge]

Hows the intake?

How was the boat running before plugs changed?
What was the last thing done with the boat before plugs?

 

[lutzinmn]

Boat ran fine when I put it away for winter. I brought it home from storage a couple of weeks ago. Hooked a hose to it and it started right up and ran fine it seemed. Decided to replace plugs because its been a few years. Thats when I noticed a couple of plugs were wet. I haven't done anything to it except change lube in lower unit and change the oil. Also, there is no water in the oil.

 

[alldodge]

In that case I would look closer at the exhaust

 

[tpenfield]

I hate it when 1992 5.7 engines leak water into cylinders.

Exhaust manifold gasket could be leaking, which would allow water to get into the exhaust and to the exhaust valves and finally into the cylinders. Usually you get water in the middle 2 cylinders (#3, #5 for example), but seeing what the exhaust ports look like is a starting point.

 

[lutzinmn]

If the exhaust manifold gasket leaks, wouldn't it just leak exhaust. Is there a way to pressure test the manifold?

 

[tpenfield]

If the exhaust manifold gasket leaks, wouldn't it just leak exhaust. Is there a way to pressure test the manifold?

there is a water jacket surrounding the exhaust. The gasket keeps the water and the exhaust separate . . . until it fails. Then water leaks from the water jacket into the exhaust.

See cut-away diagram of the exhaust manifold . . .

 

[lutzinmn]

I tested the exhaust manifold using the steps from the sticky posts. The manifold showed no leaks. I guess that leaves the exhaust manifold gasket or intake manifold.

 

[alldodge]

Look also behind the valves on the head

 

[Lou C]

Make sure the sealing surfaces of the manifolds and elbows are not eroded, this can cause the gasket to not seal. The same is true of the intake gasket where the water ports for the cyl heads are. If these leak it can put water into the intake. #1 and #3 are both on the same side....

 

[Bondo]

Look also behind the valves on the head

Ayuh,..... That's My guess,..... Cracked head,..... Been there, seen that, replaced the heads,....

 

[Lou C]

They can also rot through there...on mine I wound up replacing both heads with re-man heads.....