Norther Lights cooling system problem

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grahamdouglass

Senior Member
Joined
Nov 29, 2012
Messages
413
Location
Canada
Vessel Name
Summer Wind 1
Vessel Make
Marine Trader 41
I have a Northern Lights 5kw M643 Generator, bought last year used. 800+ hours. Runs good, does not over heat.

The problem. When I went to drain the coolant out of the engine last fall, nothing came out. I marked it down as something to be investigated latter.
This spring I checked out the generator and it has lots of coolant. So there is probably a blockage somewhere. I fired it up, it runs well. The sea water cooling side shoots out plenty of water from the exhaust.

What would be the best way to trouble shoot a blockage in the cooling system of a Nothern Lights M643 Genset? I haven't contacted Northern Lights yet, but I will ask them a similar question as well as cooling system diagrams for the M643. This genset is in a confined space (My lazerette on a MT41).

I haven't done any real trouble shooting yet. Would a plugged heat exchanger prevent water from draining?

Has anyone had a similar problem?
 
I’d call Northern lights Tech support @ 1-800-762-0165 or 1-206-789-3880

I just talked with them yesterday about annual maintenance and they were detailed and helpful.
 
First, check the impeller, it sounds like it is working but I am concerned that it has lost a fin or two which have migrated to a small passageway inside the engine. You need to find it and remove it before it migrates again to a more critical spot.

You may be lucky, it may actually be right behind the petcock which you opened to drain the block, remove it and dig around.

Can't imagine why you would want to drain the coolant though.

pete
 
I cant imagine that everything would be fine but the cooling system is blocked. What did you open to drain it? Did you open the coolant reservoir cap so it would drain faster? If you were draining from the heat exchanger there might be two drain cocks, for for the fresh water and one for the raw water.
 
The drains commonly clog. Unscrew whole drain valve and clean out the crud from the hole in the block.

Also snug the clamps on the two boots on the exhaust manifold/heat exchanger. A leak on the outer most clamps will allow salt water to mix with coolant and that will cause more crud in the water jackets.
 
The impeller has nothing to do with the coolant.

If you don’t change it at regular intervals you should test its effectiveness with test strips and put in an additive package or replace it.
 
It's the block drain that is not draining. In a closer reading of the service manual its recommended a flushing of the coolant, via the block drain be preformed yearly. It also recommends cleaning the heat exchanger. So I imagine a good cleaning on both the fresh and salt water side is inorder. I don't know if a pipe cleaner will fit up the drain hole in the block drain but I will clean away to see if the simplest of solutions will solve the problem.

I think the fresh water pump has a metal impeller so it is probably crud built up in the block and or passage from which the water drains.

The biggest problem is access.

Thanks for help
 
The drains commonly clog. Unscrew whole drain valve and clean out the crud from the hole in the block.

I would for sure try this first. Notice it says to remove the drain cock and clean. I don't think you can run anything thru the drain cock. Also, it will drain faster if you loosen or removed the coolant cap.
 
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