SailNet Community banner

1 - 9 of 9 Posts

·
Registered
Joined
·
2 Posts
Discussion Starter #1
I have a clog in my seawater cooling system on a Universal 5411. The clog seems to be somewhere before the temperature sender (when I remove the sender no water comes out and this is the 1st access point after the water enters the block).

I know I need to de-scale the engine somehow (acid, vinegar, other stuff) but until I free up the clog I can't do anything except overheat the engine.

So, I would welcome suggestions for freeing up the clogged cooling system. The more specific the instructions the better.

One idea I have is to force some water into the system (hose hooked up to the sea water in), keeping the temp. sender port open until water flows through. Not sure if this is a good idea so I really need help.

Thanks
 

·
Registered
Joined
·
847 Posts
Are you sure that you are actually getting water from the seacock to the engine? That would be the first thing I would check, apologies if you have already done so.
 

·
Registered
Joined
·
1,600 Posts
Follow your hoses. As FSMike said, make sure your seacock is open. If it is, probably the next stop is a sea strainer. Close the seacock and open the strainer to make sure it is not clogged up.
If the seacock is open and the strainer is clear, make sure there are no kinks in any of the hoses.

If the strainer looks good, slightly open the seacock to see if seawater comes thru. Depending on water coming in or not coming in, will tell you if the blockage is before the strainer or after.

What kind of boat do you have? Any chance that the bottom is so dirty that the water intake is clogged?
Is this a new problem for an old boat that you have owned for a while or did you just get the boat?
 

·
Registered
Joined
·
846 Posts
You should check and control your sea water passage from the block. The temperature sender cannot be at the enterance of water but should be very near to exit (Exhaust) otherwise it will not measure the "heated" water.
 

·
Registered
Joined
·
421 Posts
Don't force water through, you can blow the head gasket end up with water in the crankcase.
I would remove the alternator bracket / water manifold (where the temp sensor is) and see if water comes out there. If no water there then it's got to be the inlet behind and under the water pump. Could be just the temp sender hole is plugged you can see that once the manifold is off.
Have you ever had an impeller lose vanes? Could be one stuck in the engine block inlet valve.
 

·
Registered
Joined
·
2 Posts
Discussion Starter #7
My original post was a bit confusing sorry. Water flow through the pump is good, so i know water is getting to the engine (though when I noticed the problem the sea strainer was full of ick, some of it rust colored - probably where clogging material came from), it's just not making it to the exhaust or even recirculating (no water is making it to the temp. Sender on the front of the engine).

The boat is relatively new to me (2 years) but has been owned by a friend and good mechanic before that, before him it sat for a while. Engine has been pretty flawless for the past couple of years though.

Hull and water intake are clean.

Keep ideas coming please.
 

·
Registered
Joined
·
421 Posts
Check the inlet to the block, there's a drain valve in it which might trend to get clogged. If you're getting water out of the pump that would be the next place it could clog. I don't think there are any passages inside the engine that could completely shut off the water flow, so I'd bet on the inlet fitting and valve. Like I said before if the pump ever lost a vane that could be plugging it up. Could have been in the hose for some time and just now stopping the flow. How's the current impeller look?
 

·
Registered
Joined
·
2,869 Posts
are you sure the pump is pumping or is the water just flowing through because it is below the waterline. if the vanes are broken off the water will flow but with no pressure.
 
1 - 9 of 9 Posts
Top