Perkins 4108 Coolant Prop Movement Pump

[SV Someday Came]

Hello

I have some question about my Perkins 4108 in my Willard sailboat.

1. I am loosing coolant. I have watched the overflow tank for the past two weeks and without the engine running, the level continually drops. When I run the engine, the level can drop a 1/3 of the container quickly. I have checked the hoses. There is no coolant leak. Where else is it possible to loose coolant on this engine?

2. The Perkins 4108 is attached to a V Drive transmission. When the engine is in neutral, the prop continues to turn albeit at a very slow rate. You can see the shaft slowly turning in the engine compartment. Is this normal?

3. The rear of the engine (actually I guess it is the front since the engine is in backwards) is somewhat wet with water. I have heard that this is where the water pump">raw water pump is located. The manual suggest rebuilding this pump if it is leaking. Does anyone know of a good source of Perkins parts where they won't mind a question or two... or 5!

Thanks

Michael

[Alan Wheeler]

I will answer question 2 first. Yes. The shaft turning can be quite normal. However, I suggest you check the oil level, and most importantly, that the correct fluid is being used. If you have not changed the oil in some time, I suggest you do so. Apart from that, the friction of the oil internaly sometimes makes the shaft slowly turn around. There is no driving force on the prop however, so the boat will not move forward.

Are you sure problem 1 is not related to problem 3?? Otherwise a common place to lose coolant is the heatexchanger. Check carefully as it may have an internal leak.

[Maddog]

Originally Posted by MV

Hello

I have some question about my Perkins 4108 in my Willard sailboat.

1. I am loosing coolant. I have watched the overflow tank for the past two weeks and without the engine running, the level continually drops. When I run the engine, the level can drop a 1/3 of the container quickly. I have checked the hoses. There is no coolant leak. Where else is it possible to loose coolant on this engine?

You could be losing it through the heat exchanger and out with the raw water exhaust. Check your exhaust. See if its green.

2. The Perkins 4108 is attached to a V Drive transmission. When the engine is in neutral, the prop continues to turn albeit at a very slow rate. You can see the shaft slowly turning in the engine compartment. Is this normal?

What Wheels said.

3. The rear of the engine (actually I guess it is the front since the engine is in backwards) is somewhat wet with water. I have heard that this is where the raw water pump is located. The manual suggest rebuilding this pump if it is leaking. Does anyone know of a good source of Perkins parts where they won't mind a question or two... or 5!

On the top and bottom of the raw water pump there are weep holes behind the pulley. If it is weeping water or oil, the seals are shot. But a new one. The best source I have found is Trans Atlantic Diesel. Look them up on the web

Thanks

Michael

My answers are in italics above.

[donradcliffe]

The raw water pump is not a perkins part--it is probably Jabsco--get part numbers off the front and see what you can find for new seals and bearings...they are expensive pumps, but not that hard to rebuild.

The freshwater loss does sound like a heat exchanger problem--in addition to the engine cooling hx, do you have the engine plumbed to a boat hot water heater?? In any case, you will probably want to isolate the hx and see if it holds water. There are several models for the 4108 hx.

[CSY Man]

Coolant could also be lost in the head from a blown head-gasket...?

No reason to have a "wet" engine: If you go after every little leak and weep, the 'ol Perkins can be dry as a bone...

Also, if you keep the coolant tank too full, it will spit out the excess when it warms up, then you will think you lost fluid and top it of again, then loose it, etc.. (Not that I have never done that. )

The fluid level should be at least an inch below the cap.

Even under normal ops, it will occasionally spit out some now and then from the "overflow" vent on the cap flange.
I got tired of the green stains below the engine so I installed a plastic hose leading to a plastic bottle secured in the a corner below the engine. Now the blanket stays clean, and I can recycle the few ounces of coolant that finds it way to the bottle: Maybe half a cup per month or so.

BTW, a Perkins cap cost $30.00, a cap with the same pressure rating from the autopart store is $7.00.

[Fasttimes]

Be care ful here because if seals go on fresh water ie engine recirculating pump ,the water goes directly into your oil sump

[SV Someday Came]

really wonderful information, thank you folks so much. I always thought in preparation for my sail to the world that I would be spending tons of money and time on sail training. I never dreamed I would be working and spending so much on the diesel, the electrical, the woodwork, the plumbing, and the brightwork. Maybe I am doing all this backwards.

[Chief Engineer]

Get a radiator pressure tester/or borrow one.
With the engine off pump it up to the value of you radiator cap...let it sit and observe if there is any decrease in pressure.

Start the engine and see if the pressure rises...this may tell you if you have a blown headgasket.

Also hot water heaters can be a source of loss of coolant...I have seen some pretty ratty hose used in hooking up hot water heaters

[jscott]

Blown head gaskets usually result in exhaust gases (or inlet gases) going into the coolant when operating the enigne these gas appear in the coolant reservior and are vented there, so check for bubbles in the coolant reservior or gases coming out of the reservoir.

Really sounds like the pump seals are shot.

[SV Someday Came]

Originally Posted by MV

Hello

1. I am loosing coolant. I have watched the overflow tank for the past two weeks and without the engine running, the level continually drops. When I run the engine, the level can drop a 1/3 of the container quickly. I have checked the hoses. There is no coolant leak. Where else is it possible to loose coolant on this engine?

I feel silly answering my own question a year later, but I have finally tracked down the leak. The leak over the past year had gotten worse. I was loosing about the amount in the overflow tank (the plastic tank off to the side). That is a lot ofcoolant!! But then, I so rarely took the boat out since one thing after another would break!

On our last trip out where I posted the Wind and Wing question, the engine made a very bad sound off and on. We got back and I finally figured the sound was from the impeller. I removed and had the impeller replaced and the pump rebuilt. But while I was back there in that god-awful restricted tiny ass spot I noticed that the entire pump looked pretty well rusted. I could see little stalactites on the bottom of the access plate to the heat exchanger. I figured the gasket was the culprit and I removed the plate.

Took it to Captains Locker to get a new gasket and the guy there said "here is your problem" and proceeded to stick his pen knife through the plate!!

Why Perkins would have made that plate out of aluminum, I do not know. I suppose it did hold up these 45 years...

Anyways, my point is that the coolant was simply passing through the actual metal and raining out onto the impeller! This ability of liquid to pass through metal is amazing.

I took the plate to Nacho and he made a new plate out of stainless steel for me.

It took a while to track down that leak, but I am telling you, it never left my mind that somewhere I was loosing coolant during the past year!


Michael

[Chief Engineer]

I am serious....don't you get kind of a warm fuzzy feeling when you track down a problem like that?

Well maybe not warm/fuzzy...but surely satisfying.

[SV Someday Came]

Oh, it felt warm and fuzzy and satisfying and PERFECT to know I solved it and fixed it! And I am getting that feeling more and more as these days go by. I have noticed though each time I get that feeling I have less money. I am not sure to what extend, but there is a correlation between that feeling and money.