2006 ZR6 Overheating

[NicksNautique's]

Hey guys, just had a great day on the water when my ZR6 flashed an engine too hot warning.
I have a closed cooling system fitted, i topped up the coolant reservoir and check for any leaks and couldnt find any.
In idle the boat will overheat but remains cool when running above 1000rpm.
I havent checked the impeller yet.
Immediately after running i checked the coolant reservoir and when i removed the lid the coolant seemed to have lost of air bubbles in it.

Any thoughts??

2006 210 Team

[NautiqueJeff]

Very likely it is the impeller. Even though you have closed cooling, the raw water cools the heat exchanger. If the impeller is damaged, this cooling water will be restricted.

[HS]

Fresh Water Flush?

FWIW: If it has Fresh Water Flush, check for a loose cap -- This has not happened to me but somebody once mentioned to me that if the cap is not tight it could cause an overheat...

[wskiboy]

check your o ring on your sea strainer . i was missing mine,and my boat kept overheating .

[NicksNautique's]

Thanks guys i will get a chance to check it all out on Wednesday, then i will check back in and let you know.

[NicksNautique's]

Fixed??

OK got impeller changed out, also checked the strainer backet elbows and found they were very loose. taped them up and reattached them. Also checked all the hoses for air leaks etc. Had a little water on manifolds so i nipped them down a bit tighter. Other than that its a water test later to see what happens next!!!


Thanks for all advice so far!!

[ers906]

Just to clarify for my own knowledge, there is a raw water intake in a closed cooling system?

[j2nh]

Just to clarify for my own knowledge, there is a raw water intake in a closed cooling system?

Yes there is. Raw water is taken in through the same place it would be taken in if a boat did not have closed cooling. Raw water is required to:
Exchange heat with the closed loop (antifreeze) cooling system
and
add water to the exhaust manifolds to cool the exhaust system of the boat.

If you did not have this open water system the engine would overheat because of no energy transfer away from the antifreeze and your exhaust system would melt. Not sure which would happen first.

NicksNautique's, that impeller doesn't look that bad and shouldn't have given you an overheat alarm. I think you may have found the problem with the elbows. Any air leak on the suction side will mess things up.

[NicksNautique's]

Ok i'm hoping the water test goes to plan.

Thanks

Nick

[teamseal]

Dont be afraid to change the impeller once a year on a ZR-6 motor as it is a PITA to get all the rubber parts and re-burp/purg the system once the coolant has been blown out especially on the cat motors.
Make sure the gasket is in place on your water filter, I recieved a call over the weekend of a guy that threw his gasket overboard when he cleaned the cup and strainer screen and he did not notice it gone when he reassembled it.. Overheated right now!!!

[j2nh]

Spot on from TeamSeal.
Impeller is cheap, lost day on the water is priceless. Change it every year and keep a spare in the boat. Same for that stupid gasket on the strainer. I know of two people who have lost theirs cleaning the cup and dumping the gasket in the lake. Get a spare, keep it in the boat.

[NicksNautique's]

Seems to be going good!!

Ok guys running temp 159-168 on average for 2 hours tonight. Everything seems stable.
Thanks for all your input so far. I do think i have a loss of coolant, though only on a small scale. Any suggestions of where to start the faultfind??

Thanks!

[NicksNautique's]

Guy's i'm on a roll found that too and got it fixed up!!!
Boat is back to normal.....

Love it...

[wskiboy]

i am glad you fixed your problems . i have been told and have noticed that everytime i top up the resevoir and next time i check it the level down about one inch then i would fill it back up down one inch i dont know where it goes . now i dont fill it right to the top and have had no level change all season . ski-on