Impeller Veins Missing Inside Raw Water Cooled 5411

[dadster3]

Take off the raw water inlet end of the heat exchanger. Almost certainly you will find all or most of the pieces. Some pieces could be in the inlet hose, but, given my recent experience with the same issue, the end of the heat exchanger is probably where they are.

While you're at it, take off the other end and clean out any zinc particles.

[billgewater]

Had the same problem. Although the larger bits were stuck in the Jabsco pump outlet, I decided to keep looking until I could account for all the missing parts. Some were at the heat exchanger.

Does anyone use a gauze filter after the water pump">raw water pump? e.g. a transparent bodied plastic inline filter able to operate at the increased water pressure. Considering the potential problems of blocked heat exchangers, exhaust elbows etc. it may be worth considering. The presence of any debris in the filter would be the warning sign that all is not well with the pump.
Impeller pumps fail ultimately but "it all depends". Some will fail if left static for a short time i.e. not rotating. Some last for ages if used regularly. Regular replacement may sound OK but at $100 for an impeller it's a bit discouraging.
Some pumps have a transparent face allowing inspection but I have not seen these around lately. Are they too fragile? Even if you do have a clear face on the impeller, it won't catch any broken bits of a vane.
Comments?

[Sailmonkey]

Originally Posted by dadster3

Take off the raw water inlet end of the heat exchanger. Almost certainly you will find all or most of the pieces. Some pieces could be in the inlet hose, but, given my recent experience with the same issue, the end of the heat exchanger is probably where they are.

While you're at it, take off the other end and clean out any zinc particles.

Raw water cooled, no heat exchanger

[chasfgr]

Depends on if it's a raw water cooled engine or has an intercooler.
Raw water cooled it's probably gone into the muffler.
Fresh-water cooled it's probably stuck in the start of the intercooler.
Unless the engine is running hot, I'd let sleeping dogs lie and wait for the bits to come out in the exhaust.

[qwert]

[QUOTE=billgewater;3438220]Had the same problem. Although the larger bits were stuck in the Jabsco pump outlet, I decided to keep looking until I could account for all the missing parts. Some were at the heat exchanger.

Does anyone use a gauze filter after the raw water pump? e.g. a transparent bodied plastic inline filter able to operate at the increased water pressure. Considering the potential problems of blocked heat exchangers, exhaust elbows etc. it may be worth considering. The presence of any debris in the filter would be the warning sign that all is not well with the pump.

Yes did this several years ago. makes no difference to the flow and if a vane were to fall off it's a five minute job to remove it (on a volvo 11c)

[dbcreed]

I had a 5411 Universal in the Catalina 27 we had for 5 years. The impeller that came apart when I first bought her was never found. May be the only benefit of being raw water cooled!

[Searles]

Most definitely vanes ,get every piece ,dont risk cooking the motor,clean out the cooling passages while you are at it .⛵️⚓️👍

[fox9988]

I found several vane pieces in the water pump ports, both the inlet and outlet. I didn't find any pieces in the thermostat or thermostat housing. I back flushed the engine from the thermostat housing through the water pump (cover removed), with the full flow of a water hose, no noticeable resistance.
Now my engine will eventually overheat unless I pinch closed the recirculation hose, this forces the hot water to exit through the muffler instead of heated water recirculating endlessly. I've blown through the thermostat housing to muffler hose by mouth, no noticeable resistance. The thermostat is new and I've verified that it opens when warm and closes when cool. With the recirculation hose pinched closed, the engine never gets up to operating temperature (as if the thermostat isn't closing).

To recap- With the recirculation line open, the engine overheats. With the recirculation line closed, the engine never gets warm.

[fox9988]

http://downeasteryachts.com/wp-conte...nce-manual.pdf

5411 cooling system diagram on page 36.

[hpeer]

To recap- With the recirculation line open, the engine overheats. With the recirculation line closed, the engine never gets warm

Ignoring the thermostat that sounds correct.

With the water being directed through the recirculating line it just meeps going round and round and getting hotter and hotter.

With the recirculating line closed the water is then forced out of the engine and fresh (cool) water is brought in, which runs through the engine and removes heat.

The engine should start with the thermostat directing water to the recirculating system. As the engine warms up the thermostat then opens and sends water and heat out the muffler.

If your engine is over heating, but the thermostat operates then it may be that the thermostat is never getting warm enough to operate.

My MD7 operates differently. At low temperatures the water circulates through one route and some water runs through the gallery the T stat sits in. The cooling water bypasses part if the path. When the T stat gets hot it blocks off the bypass and opens the longer path. Until the T stat cools and closes. Here are some small holes that allow the cooling water to wash over the T stat so it can sense the temperature.

I am not quite seeing how that is happening in your system. I have to paste so I can read.

Look at Step 8 and read closely. I suspect that your problem may be in those unspecified details of how the small bit of water moves.

PS: REALLY NICE write up on engine.

[fox9988]

"If your engine is over heating, but the thermostat operates then it may be that the thermostat is never getting warm enough to operate."

I've removed the 143F thermostat when the engine was 180F, the thermostat was opened.
I'll study the thermostat housing a little closer and try to determine how step 8 is accomplished. The closed thermostat prevents the water from entering the exhaust, forcing it to recirculate. But an open thermostat doesn't prevent the water from recirculating, I think it can both enter the exhaust and/or recirculate.

Also, there is no water coming out of the exhaust until I pinch the recirc hose closed, none. When I pinch the recirc hose closed, lots of water comes out of the exhaust.

[hpeer]

Yes, the paths are operating as intended. Something odd is happening in the water steering.

I know you say you took the T stat out at 180. But not instantly, you had to shut the engine first.

PERHAPS the T stat is staying closed as long as water is circulating. But when you shut the engine there is enough residual heat to open the T stat?

Where is the T stat relative to the temp sensor? Perhaps that is a clue, the sensor is heating up but not the T stat.

[Captain Graham]

I recommend you setup a backflush for the engine.
Back flushing will push anything back the way it came in.
It is easy to do for the 5411
Have a bucket of distilled water (you can also add a little vinegar it your want)
Get a bulge pump and some hoses.
Remove the thermostat and with the engine off circulate the water thru the engine for 2-4 Hours. (it will take some time to dislodge some of the pieces)

Here is a video flushing a 5411 but I would recommend you reverse the flow and use a bucket to recirculate it for 2-4 hours

https://www.youtube.com/watch?v=muG4HofEYto

[fox9988]

Thanks for the ideas.

From the internet. He was having an Universal 5411 overheating issue, no mention of him trying to pinching off the recirc hose to force cooling:
Kerry, The problem is now resolved. The thermostat has 2 small holes in the flared seat. When installing the thermostat it must be seated so both holes are open on the seat. There is no indicator on the thermostat or the thermostat assembly to guide it. The thermostat just drops in place but there is only a small area in which the holes are open. The manual does not mention this and all the "experts" I consulted did not know this. This allows a small amount of water to pass through to the exhaust at all times. When the temperature rises to 143 degrees the thermostat opens and all the water passes through to the exhaust at the same time cutting off recirculation flow back to the throughhull input, thereby causing the water pump to pick up new cold water. This new cold water cools the engine, closes the thermostat and the process starts all over again. Thanks for your input. I hope you learned something about small universal diesels

Rodney

I've seen the two 1/8" holes in the thermostat flange. So I read, they let a constant small amount of cooling water enter the exhaust system to cool it. I didn't realize they needed to be oriented a certain way. And I don't know how their orientation prevents larger amounts of water from entering the exhaust when the thermostat opens. Interesting.

[hpeer]

Now that you mention it I believe my MD7 T stat has 2 small holes also.