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Uneven cooling in a 5.0

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qslim

New member
Hello all,

I just purchased a 2005 Monterey with a 5.0 & Alpha outdrive. It ran like a champ when I purchased it, though as a preventative measure I went ahead and replaced the risers, spacers, manifolds, and thermostat as well as other maintenance items like the fluids, separator, etc.. Now that everything is back together I'm noticing that the risers are cooling unevenly. Typically the left riser will be cool to the touch while the right riser is too hot to touch. What I have noticed is that when I pinch the feed hose to the cool left riser, the right riser will then cool down and vice versa. Both will be cool for a few minutes and then one will heat up. It looks to me like water is fed from the thermostat housing via a t-valve with two check balls (one going to each riser). The check balls inside the t-valve move freely.

Any ideas where I can look next?
 
uneven temps is normal........as much as twenty + degrees is not uncommon........nature of the beast...

The check balls may not be opening equally due to one opening and allowing the water to flow so the other does not open as much restricting some of the flow. Path of least resistance....

Newer designs don't use the poppet balls they use fixed orifices (specific diameter holes)
 
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kghost said:
uneven temps is normal........as much as twenty + degrees is not uncommon........nature of the beast...

The check balls may not be opening equally due to one opening and allowing the water to flow so the other does not open as much restricting some of the flow. Path of least resistance....

Newer designs don't use the poppet balls they use fixed orifices (specific diameter holes)
Click to expand...

Thanks for the reply Jack. I was wondering about that poppet valve. It may have been like this before I replaced everything, of course I wouldn't know because I wasn't paying attention to any of it. However I would suspect that the differential is more than twenty degrees... One side is literally cool to the touch while the other side is too hot to lay a hand on for more than a second. I have a laser thermometer but I didn't have it with me in the water when I was checking it. I got to thinking that maybe there isn't enough pressure to supply that tee manifold for both poppets to fully extend? I ordered the belt-driven water pump, I doubt it's ever been changed. Maybe I'll run it on the water and see what the actual temp differential is with a laser?
 
Well look close at the balls

they spin and wear so if they are not completely round or have a ton of build up on them take them apart and clean them or if worn out a bit take it apart and spin the balls around to get a new round surface.........Maybe that will help..

other wise the springs are worn and I am not sure you can get new ones.....I assure you under power at 2000 rpms or so there is plenty of water flowing thru both elbows.

Other than that the only thing left is the impeller...if it is worn or has taken a shape then loss of flow would be the result.
 
kghost said:
Well look close at the balls

they spin and wear so if they are not completely round or have a ton of build up on them take them apart and clean them or if worn out a bit take it apart and spin the balls around to get a new round surface.........Maybe that will help..

other wise the springs are worn and I am not sure you can get new ones.....I assure you under power at 2000 rpms or so there is plenty of water flowing thru both elbows.

Other than that the only thing left is the impeller...if it is worn or has taken a shape then loss of flow would be the result.
Click to expand...

I'll check it out Jack, thanks.
 
Post the Serial Number and a picture of your engine. There are a few different water systems for your engine. You may or may not have check balls.
 
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If everything is in place as it should be, I would be looking for air in the water stream coming from the drive. Some clear hose in line from the drive will do it.
 
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qslim said:
Hello all,

I just purchased a 2005 Monterey with a 5.0 & Alpha outdrive. It ran like a champ when I purchased it, though as a preventative measure I went ahead and replaced the risers, spacers, manifolds, and thermostat as well as other maintenance items like the fluids, separator, etc..
Unless your boat sits low, and with a water line that is high, your engine may not be equipped with Risers.
I'm thinking that you'd have manifolds and elbows only.
If you do have risers/spacers, make sure that the seawater transfer ports are clear of any gasket blockage.
Likewise if only mans/elbows!

What I have noticed is that when I pinch the feed hose to the cool left riser, the right riser will then cool down and vice versa. Both will be cool for a few minutes and then one will heat up. It looks to me like water is fed from the thermostat housing via a t-valve with two check balls (one going to each riser). The check balls inside the t-valve move freely. Any ideas where I can look next?
One side running cooler/other side running warmer, is somewhat normal..........., but it doesn't mean that it's acceptible!

Not sure what Left/Right means.... but nonetheless:
Rather than to restrict the cooler side, find out what's blocking or restricting the side that runs warmer.
Perhaps find a way to open up the warmer side passages/fittings a bit.
Look at all fittings, look at the seawater outlet of the T-stat housing (for the side that is running warm), and even look at the interior of the seawater supply hose.
Click to expand...
 
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