5.7 Overheating

QBhoy

Fleet Admiral
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Mar 10, 2016
Messages
8,286
Just checked the ps cooler intake. Dry as a bone. Sigh. I guess I need to take the outdrive off again and make sure everything is right.
Yeah. For sure. Best of luck and let us know how you go.
 

QBhoy

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Mar 10, 2016
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8,286
Just checked the ps cooler intake. Dry as a bone. Sigh. I guess I need to take the outdrive off again and make sure everything is right.
Just before you do. Can you send a pic of the muffs on the drive, that you are using ?
 

Darcher99

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Sep 29, 2022
Messages
24
Here's a weird question...but the tube that connects to the impeller housing. Does it just slide in to the hole in the upper unit? Or is it supposed to be fixed there? It was a bear trying to get them both to line up when I was trying to put the lower unit back on, and have very little confidence that I actually did.
 

Bondo

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Apr 17, 2002
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70,468
Here's a weird question...but the tube that connects to the impeller housing. Does it just slide in to the hole in the upper unit? Or is it supposed to be fixed there? It was a bear trying to get them both to line up when I was trying to put the lower unit back on, and have very little confidence that I actually did.
Ayuh,..... You stuff the tube into the fittin' in the upper, then carefully slip the upper into place, makin' sure the drive shaft, water tube, 'n shift shafts are all perfectly aligned,....

The tube is held in the upper by o-ring resistance,.....
 

zellerj

Petty Officer 2nd Class
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Dec 13, 2017
Messages
135
The white tube you get in the impeller kit slides into a copper water tube coming down from the upper. Sometimes an overheat melts the plastic fitting the copper water tube slides into in the upper, and you have to replace this if melted. You can see if copper tube and the white plastic tube are aligned when putting the two halves together and inserting correctly by looking in the exhaust opening in the front of the outdrive. It is not difficult, but might take a couple of tries.
 

Darcher99

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Sep 29, 2022
Messages
24
Ayuh,..... You stuff the tube into the fittin' in the upper, then carefully slip the upper into place, makin' sure the drive shaft, water tube, 'n shift shafts are all perfectly aligned,....

The tube is held in the upper by o-ring resistance,.....
There’s an o ring in the upper? Because mine didn’t have an o ring. It just stuff in there. Considered using rubber cement to put it there.
 

Bondo

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There’s an o ring in the upper? Because mine didn’t have an o ring. It just stuff in there. Considered using rubber cement to put it there.
Ayuh,...... If there's a problem with that fitting, why not fix it properly,..??
 

Darcher99

Cadet
Joined
Sep 29, 2022
Messages
24
There’s an o ring in the upper? Because mine didn’t have an o ring. It just stuff in there. Considered using rubber cement to put it there.
I’m going to fine an o ring and do it right. I was just saying I considered putting something on it because it didn’t seem right.
 

Lou C

Supreme Mariner
Joined
Nov 10, 2002
Messages
11,802
That part of the cooling system must be 100% right by the book, your Alpha pump is at the bottom most point, any leak point will bleed off water pressure and remember that water has to travel UP about 18" to go through the transom mount and then, about 3.5' forward up to the engine.
My OMC Cobra has a plastic guide that goes into the the lower water tube grommet and this guides the tube into the grommet so it all fits correctly. I've had it apart a few times with no problems afterward. The Cobra pump is in the upper gear housing so any looseness in the fit of those gaskets can cause it to pull in air when the boat's up on plane.
The Bravo and Volvo engine mounted pump systems are even more sensitive to this because the pump must pull water all the way up to the engine, any air getting in can cause hot running or overheating.
 
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