Overheated 5.7 engine- what happens?

[piratedude]

My impeller went while wifey driving boat...overheated engine and stalled- Cranks slow and wheezes but I got it to restart and it ran really rough. 2006 5.7 gm engine w/ bravo2. Can anyone give input on what possible damage happens when inpeller goes out? Are the heads toast?

 

[BAproject]

Re: Overheated 5.7 engine- what happens?

What happened when the impeller failed...did a vane break off? If that happened then the rubber piece may have been sucked into the system. You have to pull the hoses and t-stat housing and see if you can find it. Since you have to replace the impeller, drop the lower unit and inspect and look for all pieces.

Also, when the impeller failed how long did you run after. Did you over heat the engine? If that happened then the exhaust flappers inside the large exhaust hoses may have melted and sealed of the exhaust passage...that might explain the wheezing

-BAproject

 

[zbnutcase]

Re: Overheated 5.7 engine- what happens?

A lot could happen as these late engines castings are extremely thin. Head or block deck could be warped, they could be cracked, or you might get lucky and just need a head gasket. Expect the worst, hope for the best!

 

[wire2]

Re: Overheated 5.7 engine- what happens?

A compression test will tell you if the heads are warped. They typically lift in the center, which allows the gasket to fail between 3-5 and 4-6

 

[squeak911]

Re: Overheated 5.7 engine- what happens?

I have read that the hot exhaust gases could melt somes seals in the outdrive. A Pressure check will let you know. My impeller went out on my alpha one. The Upper Unit Water Pocket Cover was melted on mine and needed replaced.

 

[Brentathon]

Re: Overheated 5.7 engine- what happens?

Overheating is the number one killer.
I overheated, and it first toasted my Alpha outdrive.....major mechanical failure, sounded like someone was rapping it with a hammer.
Not long after, my engine hydro-locked.......probably due to a head gasket, or head warping.
So.......I basically destroyed the drive and engine.......now I watch the gauge a lot!

 

[Bondo]

Re: Overheated 5.7 engine- what happens?

overheated engine and stalled- Cranks slow and wheezes but I got it to restart and it ran really rough.

Ayuh,.... When overheated, til it QUITS,... Alot can,+ does turn to Junk...

Just ask This guy....

My guess is, you're looking at a Long Block, at a very minimum....