Fresh Water cooling water dirty brown

sailak · #1 07-23-2009

I took a peek at the coolant this weekend expecting to find the nice green of antifreeze, instead finding an ugly brown/rust colored water.

Normal?

Any tricks to draining the coolant, flushing and refilling?

Yanmar 3GM30F...where the heck is the heat exchanger?

pdqaltair · #2 07-23-2009

Quote:

Originally Posted by sailak

I took a peek at the coolant this weekend expecting to find the nice green of antifreeze, instead finding an ugly brown/rust colored water.

Normal?

Any tricks to draining the coolant, flushing and refilling?

Yanmar 3GM30F...where the heck is the heat exchanger?

Such as an air leak or a head gasket. Sometimes electrolisis from a bad ground. AF doesn't generally fail to that extent on its own....

But it could be that you are looking at orange AF (Dexcool or similar) or just plain neglect over a long time.

I would change it and then watch closely.

timebandit · #3 07-23-2009

So, how long since you last looked at it??

Changed it how long ago??

sailak · #4 07-24-2009

Quote:

Originally Posted by timebandit

So, how long since you last looked at it??

Changed it how long ago??

Just took possession of her on May 19th...unknown how long since it was changed. I've been watching the level of coolant in the overflow bottle, just decided to dig deeper as I go through systems to figure them out.

timebandit · #5 07-24-2009

It could be that perment antifreeze or it could be a problem.

I would change it out so I would know where I stand.

Talk to someone in your marina for what to use.

I'm in an area that we call that stuff "COOLANT".

sailak · #6 07-24-2009

I'm planning on changing the coolant out on Monday when I go back down to the boat.

Drain from the bottom or pump it out like the oil?

captbillc · #7 07-24-2009

if you have the engine manual it will show the drain plugs or valves. or you can drain all the low spots in the coolant side of the system. the engine block, heath exchanger ,oil cooler if it has one & transmission cooler unless that is sea water cooled. i would put water in & run it & drain it again to clear out the crud.

badsanta · #8 07-26-2009

There are several drain valves on this engine that you need to open. On mine it has a little clear 1/4 inch tube attached to each one. The heat exchanger is the part with the radiator cap. If the engine is cold it is safe to take it off for a look. You should have it loose for it to drain properly.There is no one drain valve like a car radiator. Your heat exchanger is the radiator. Also change the oil and filter. My 3GM30F calls for #30 diesel oil and the same for the transmission. I change both at the same time I do it at 100 hours or twice a year. Good luck

badsanta · #9 07-26-2009

Also the little pump with the small fan belt is your fresh water pump. The inside impeller has to be replaced. Most people do it every wear. The easiest way to do this is to remove the whole thing because the plate you take off is inboard to the engine. It is impossible for me to replace the impeller with out removing the pump. But that's me. Lots of info on this engine. Keep searching.

sailak · #10 07-29-2009

Flushing the coolant went well but is rather time consuming with the repeated draining, bringing up to temp, draining, etc.

As for changing out the impeller...since I started up with the engine with the through-hull closed -- (hmmm, that's odd...I don't hear that splashing sound...OH CRAP) -- I thought it wise to change the impeller even though it did put out a good flow of water after I opened the through hull.

I did as others have posted and removed the pump. The pics below are of the impeller I removed. To me it appears to be in good condition. I have no idea how long it's been in service.

Where do you guys buy your Yanmar parts? I went to the local "Yanmar dealer" and was underwhelmed by the response I got. They don't stock impellers, seemed indifferent to ordering parts for me. Any online options?

Thanks for the help.