Thermostat replacement on closed cooled motor

[sstexan]

Guys,

I am having issues with my boat temps creeping up while I am getting on it pretty hard. I was part of the defective impellers a few years back from White Lake (They sent me new ones very quickly!) . My impeller was completely destroyed. That being said, I am trying to determine where the blockage is down stream.

Correct me if I am wrong, but the thermostat in a closed cooled boat is on the coolant side of things. There should be no way a torn up impeller reaches the thermostat? I was pulling the thermostat yesterday and coolant begin to drip out of the thermostat area. Am I missing something here?

Should I dismantle the exchanger and clean that out? It seems to be the most logical place for debris to get stuck?

BTW- My motor is a 2007 ZR6.

Thanks,

SSTEXAN

[sstexan]

Nobody here? I am really trying to pinpoint my overheating problem. I think its on the raw water side downstream from the impeller. My assumption would be to dismantle the transmission coolant hoses and v-drive hoses and flush those out and then make my way to the exchanger. I was going to go ahead and flush the anti-freeze as well since I am taking the exchanger apart. Am I missing anything? I just don't see how the thermostat could have impeller fragments on my closed cooling system. Appreciate any and all comments. Thanks,

SSTEXAN

[Paxdad]

Raw water impeller parts should not be able to enter the closed loop unless there is breach and therefore the antifreeze would be fully. Diluted. I would work your way backwards if flushing the raw water side. Ie flush back toward the pick up under the boat where lake water enters and determine if you have obstruction. I would also pull impeller and inspect first. Even the good batch of impellers from white lake are inferior Chinese junk.


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[vvfdfirefighter]

I didn't respond earlier because I was confused with your question. You threw me off when you had questions about coolant being visible at the thermostat. You will always have visible coolant visible at the thermostat.

I do agree with Paxdad, you need to flush the system first. Pull the drain on the heat exchanger. see if anything comes out of it. If you don't have a filter on your raw water intake things can get stuck in the exchanger. Disconnect the hoses on the ENDS of the heat exchanger and flush it out if needed. Connect hoses back and then move to the impeller. Buy a quality impeller. saving $5 is not worth it with a lot of these things. Never start the boat without water flowing to the raw water pump. This will only advance the possibility of impeller failure.

If those options don't work, check your coolant reservoir, make sure it has the specified amount of fluid in it. Should the engine still overheat, change out the thermostat. Id say change it out anyway. its already 10 years old.

[sstexan]

Thanks for all the responses. Sorry to confuse anyone on the question. Reading through the forums, everyone always says to check your thermostat if you burn up an impeller. My questions are:

1.With a closed cooling system, is there a way for impeller parts to get stuck in the thermostat?
2. Where is the first place I should check for debris on the raw water (sea water) on my closed cooled boat for debris?
3. I was going to start at the pickup and work my way back. Per the diagram, that would be:

Pickup under boat, canister for flush winterize, impeller housing, strainer, exchanger, v drive. I was going to reverse flush all these areas. Hopefully this solves my problem.

Thanks,

[d_nodixon]

Maybe get out what you can before you reverse flush to avoid getting debris stuck somewhere between what you can now see. Not sure if you can get enough flow and pressure to effectively blow everything out any way. Pieces shouldn't reach the thermostat unless you have a more serious issue.

I shredded my impeller in my 06 because I forgot to open the inlet. Took apart all the seawater lines and got out everything I could see, which included dismantling the heat exchanger so I went ahead and changed out the coolant and thermostat while I was at it. The exchanger did have several peices of the impeller in it which I was able to get out.

Given the age of your boat, if your cooling system has not been flushed and changed recently its probably a good time to go through all of it.

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[Paxdad]

1. No unless there is a breach in the coolant side system and would most likely be in the exchanger.

2. Check the intake on bottom of boat then the strainer.

I believe where you are getting confused is in reference to checking for debris in the thermostat housing. This true on an open or sea water cooled system and not on a closed cooling system that you have.



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[sstexan]

Well, I started the process and got as far as the right side of the exchanger. Take a look at this pic. I put a new one next to the old one just to use as a reference. Do you think I should keep going? It looks to be a pretty healthy project to take the exchanger completely out of the boat. On the side of the exchanger there are 4 different ports. All of these pieces were lodged in one of the ports. No doubt this contributed to my overheating at higher speeds. Once again, I really appreciate all the input from everyone.

SSTEXAN

[d_nodixon]

Wow, that looks like it would be the most of it for sure...mine only had small peices, no lArge chunks like that

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[d_nodixon]

At least take the end caps off and shine a light through the exchanger tubes

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[ohiowake2]

I have a 01 SAN and had overheated twice. First time it took me forever to find where to look for debris. Everything you read talks about a clear water strainer. On my boat I have a clear looking strainer on the starboard side at the front of the engine compartment but about half way down the engine. This does not come apart to look at for debris. If you can locate that and follow the black hose down toward the rear of the engine compartment and all most down to the floor you will see a metal connector and this hose goes there and another on the other side and then your oil line connect on the top because this is where the oil gets cooled at. If you take the hose off the front you can feel around and check for debris there. You have to do this out of water otherwise water will come in through the hoses just by force. I have not tried on the water and don't want to be the first to try. Let me know if that helps. I will have my boat home next week I can take a pic if you like.