Ruined Engine

[kontok]

Hi everyone. I ran into an issue with my engines and it lead to a "You need a new engine" line from my Marina.
One of my Volvo Penta engines began overheating at high RPM (over 3000). I would turn the engine off and restart it and it would become cool again right away. it felt as if there wasn't enough water going through the cooling system at high RPM. So the marina told me that I need new manifolds and risers. The engine otherwise was ruining great. Today they put the boat in the water after replacing the manifolds and risers on that engine and started it up. It ran ok for a little but then started making a knocking sound. And now they are telling me i need to rebuild the engine.
Is it possible to figure out what really happened? Is it most likely a result of a bad job on the exhaust? or is it really just a coincidence? They are not volvo penta certified mechanics.

Any recommendations are greatly appreciated.

Thank you!

 

[Lou C]

Ahh there must be MORE to this story?!
Is that a cloud of white smoke behind the boat? Just how hot did the engines get?!
That sounds really bad, you might just need a new engine.

 

[alldodge]

Welcome
Which VP motor is it?
Happen to have a serial number?
Open or closed cooled?

That is a lot of white smoke coming out so first thing I would want to see is the motor and hose routing.

The knocking sounds real bad so need to know how hot did it get. Did it run fine after the over heat for any time after it cooled down and before the mans were replaced?

 

[matt167]

This is common in the Subaru boxers. Get them smoking hot and the tolerances tighten up severely and it wipes the bearings… not saying that is what happened but it’s possibly what happened

 

[kontok]

Welcome
Which VP motor is it?
Happen to have a serial number?
Open or closed cooled?

That is a lot of white smoke coming out so first thing I would want to see is the motor and hose routing.

The knocking sounds real bad so need to know how hot did it get. Did it run fine after the over heat for any time after it cooled down and before the mans were replaced?

This is the 57gce300r a199460. The motor ran fine after it cooled off at low RPM. The knocking sound started only after the mechanics replaced the manifolds and risers. it was running good for a few min but when they restarted it, it started making a noise. They told me the cylinder head cracked.

 

[Lou C]

That’s common on small block Chevrolets that are overheated
Happened to mine but I didn’t have the noise or white smoke no symptoms at all. I had water in the cyls but that was from blown head gaskets

 

[drewm3i]

That sounds terrible. Time to start taking the engine apart.

 

[alldodge]

This is the 57gce300r a199460. The motor ran fine after it cooled off at low RPM. The knocking sound started only after the mechanics replaced the manifolds and risers. it was running good for a few min but when they restarted it, it started making a noise. They told me the cylinder head cracked.

Not sure my self but don't see that, hey @muc what do you think?

 

[Lou C]

it doesn't exactly make sense does it?
I'm wondering if....someone....dropped a washer....or nut....or bolt...down the center of the exhaust passage in the manifold....while installing & didn't realize it....hard to imagine....but I guess anything's possible....

However, when my engine overheated....because the raw water hose popped off the P/S cooler and was pumping the bilge full of water....sea water....I didn't know that's what was wrong then, but in a panic decided to to try to beach the boat....didn't make it across the bay....engine was kinda sounding like that at the time....it died about half way across...then the water quit coming in and it all started to make sense.....
Then, got the boat out of water a couple days later and started it up expecting it to sound like that, and nothing, just the normal sound of an old Chevy small block....
Ran fine for 2 1/2 more seasons, then at the end of the third, got water in 2 cyls hard starting and missing, took it apart, and found the head gaskets had split on the edge of the fire ring near a water passage.
The machine shop found both heads were cracked as well.

 

[tpenfield]

Do the easy stuff first . . . People often get too much exercise by 'jumping' to conclusions.

The Easy stuff:

• Mechanics stethoscope of source of noise
• Compression test
• Cylinder leak test
• Remove valve covers to visually inspect rocker arms/lifter rods/cylinder heads
• Check oil for signs of water

Let the findings of the easy stuff guide the way.