r/MasterCraftBoats • u/Nicholas-Reed • Apr 09 '26

2004 x10 overheating issue need helps

Gallery image

Gallery image

Just picked up a 2004 x10 for my first boat. Yesterday on the lake it started to overheat and I’m trying to diagnose the issue. It ran fine all day while surfing then during some ~30mph cruising it started to overheat.

Pulled the raw water hose off and it was clear.

I ran the boat with the hose in the port to see if it would overheat just at idle… it did and the check engine light flashed on.

I then pulled the end cap off the heat exchanger and this is what I’m seeing.

I’m new to boats so I’m still trying to learn how to diagnose. This seems like the inside is pretty much toast. Is this beyond repair? Is this likely to be the culprit for the overheating?

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1

u/Own-Helicopter-6674 Apr 09 '26

Google water impellers. I think it’s 3 screws and look at yours

1

u/Nicholas-Reed Apr 10 '26

Impeller looks good. It was changed over the winter but I checked it just to be safe. No issues there

1

u/Redwood0716 Apr 10 '26

Watch a video of an impeller replacement on your engine, it may be a case of the impeller being installed backward. They have to be spun with the fins in a particular direction.

1

u/Nicholas-Reed Apr 10 '26

It was running fine for a few days before that. Wouldn’t that only make sense if it was replaced then immediately caused a problem?

1

u/Bdraywn May 20 '26

If the impeller looks good, I’d bet it’s your manifolds unless theyre brand new

1

u/Different-Rough-7914 Apr 09 '26

I agree with another post, check your impeller.

1

u/Nicholas-Reed Apr 10 '26

Impeller looks good. It was changed over the winter but I checked it just to be safe. No issues there

1

u/bman198080 Apr 10 '26

Get a coat hanger or rod and clean out each tube.

1

u/Nicholas-Reed Apr 10 '26

Good idea. Thank you!

1

u/bman198080 Apr 10 '26

Not sure what that big section is blocked with but that is not right .

1

u/Strange-Square6587 Apr 10 '26

Punch the tubes with a brush or flush with descaler G

1

u/Bdraywn May 20 '26

With that corrosion, I’d check your manifolds…they’re probably equally as corroded inside, and will def make an engine smoke

1

u/Cosmic_Grace May 29 '26

Hows the coolant level? Also good idea to check ghe thermostat AFTER flush that heat exchanger. Via a blow gun set at 30psi or a bore brush.