question on a shut off valve

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Time to change it before it breaks off and causes trouble.
I didn't put it back so as not to add zinc debris.
Is there an adapter to connect this to a vacuum?
IMG20250120235409.jpg
 
If it weren’t for the exhaust manifold needing cooled, it wouldn’t matter if there was no flow with the thermostat closed.
But since it’s a jacketed manifold there needs to be a minimum flow at all times.
There’s a thermostat bypass circuit that passes a small amount of coolant through with the thermostat closed. Usually the bypass circuit will be sufficient cooling at low rpm’s if the thermostat gets stuck closed.
There is also a hose between the extension tank and the exhaust manifold. It should be the u shaped hose in the second photo. What's the purpose of this hose?

IMG_20250121_222717.jpg
IMG20250120231609.jpg
 
I think it helps the water flow around corners much like a train on tracks.
😲
Right! You are such an f-ing nuisance. Go away.
Yeah, it's from another thread, maybe a bit too harsh here, but somehow mildly appropriate.

The OP, nor anyone deserves this kind of response. How was that helpful?

What's the mantra? Be kind?
 
😲

Yeah, it's from another thread, maybe a bit too harsh here, but somehow mildly appropriate.

The OP, nor anyone deserves this kind of response. How was that helpful?

What's the mantra? Be kind?
I didn't have time to follow the trends.
All my questions are serious.
 
😲

Yeah, it's from another thread, maybe a bit too harsh here, but somehow mildly appropriate.

The OP, nor anyone deserves this kind of response. How was that helpful?

What's the mantra? Be kind?
@luna You have lost all sense of humour.
I am sure TT may ask why you quoted him.

@paulga If you were serious in asking that question, sorry for the misunderstanding.
 
There is also a hose between the extension tank and the exhaust manifold. It should be the u shaped hose in the second photo. What's the purpose of this hose?
I, too, am curious as to the function of this hose. Can anyone elucidate?
 
There is also a hose between the extension tank and the exhaust manifold. It should be the u shaped hose in the second photo. What's the purpose of this hose?

View attachment 161604View attachment 161605
I’m not sure how the water is routed on the FL manifolds, but if I had to guess at the function, I’d say it’s part of the bypass loop for when the thermostat is closed.
Its funny, looking at the drawing, it looks like all paths head into the manifold. That can’t be right.
If the hose connects at the high point in the manifold it also helps purge put air. The little bleed valve just gets that last little bubble that’s left over.
 
If the hose connects at the high point in the manifold it also helps purge put air. The little bleed valve just gets that last little bubble that’s left over.
The hose in question does not connect at the high point of the manifold. There is another, smaller, hose with metal braid which is at the high point. I don´t think that there is a bleed valve in this area.
 
Although I am no expert in how Lehman and Smith marinized the Ford diesel, I agree with Bmarler, this U shaped hose from the Expansion Tank to the Water Outlet Adapter is likely part of the coolant bypass path that sees coolant flow only when the T stat. is cold.

I can't imagine any designer would build in such a torturous path for full time coolant flow.
 
I don't mean to display all my ignorance in one shot but Paul's schematic drawing seems to indicate that the exhaust manifold is cooled by antifreeze. Not exactly related to his question, but if this is the case, this is great news! I looked at several boats powered by Perkins (I know this is FL) that used raw water to cool (and shorten the life) of exhaust manifolds. One in particular was in fact antifreeze cooled and the owner (of nearly 20 years) had no clue of what I was even talking about. Another owner had the original installation instructions which showed cooling the manifold as part of the antifreeze circuit but actually used raw water. Like most of them I saw.

Sorry for any drift, but Paul, and the rest of us who may not be gurus, need to understand the difference of the two circuits through various engine components starting with the heat exchangers. I think Paul is working very hard at understanding his boat and he is getting a lot of good help here. The circuits get confusing when valves, thermostats, bypasses, and bleeds for potential airlocks get involved. Carry on.
 
I don't mean to display all my ignorance in one shot but Paul's schematic drawing seems to indicate that the exhaust manifold is cooled by antifreeze. Not exactly related to his question, but if this is the case, this is great news! I looked at several boats powered by Perkins (I know this is FL) that used raw water to cool (and shorten the life) of exhaust manifolds. One in particular was in fact antifreeze cooled and the owner (of nearly 20 years) had no clue of what I was even talking about. Another owner had the original installation instructions which showed cooling the manifold as part of the antifreeze circuit but actually used raw water. Like most of them I saw.

Sorry for any drift, but Paul, and the rest of us who may not be gurus, need to understand the difference of the two circuits through various engine components starting with the heat exchangers. I think Paul is working very hard at understanding his boat and he is getting a lot of good help here. The circuits get confusing when valves, thermostats, bypasses, and bleeds for potential airlocks get involved. Carry on.
Thanks.
I didn't have the chance to look at other engines closely. thought the cooling system has common design across engines.
 
😲

Yeah, it's from another thread, maybe a bit too harsh here, but somehow mildly appropriate.

The OP, nor anyone deserves this kind of response. How was that helpful?

What's the mantra? Be kind?
I have to admit, this made me laugh.
 
I’m not sure how the water is routed on the FL manifolds, but if I had to guess at the function, I’d say it’s part of the bypass loop for when the thermostat is closed.
Its funny, looking at the drawing, it looks like all paths head into the manifold. That can’t be right.
If the hose connects at the high point in the manifold it also helps purge put air. The little bleed valve just gets that last little bubble that’s left over.

the u hose is tapped to the fresh water pump inlet. it seems like the coolant flows from both the expansion tank and the exhaust manifold through the pump to the engine, then through the t stat housing and bypass to the heat exchanger.

IMG20250120231909.JPG
 
I don't mean to display all my ignorance in one shot but Paul's schematic drawing seems to indicate that the exhaust manifold is cooled by antifreeze. Not exactly related to his question, but if this is the case, this is great news! I looked at several boats powered by Perkins (I know this is FL) that used raw water to cool (and shorten the life) of exhaust manifolds. One in particular was in fact antifreeze cooled and the owner (of nearly 20 years) had no clue of what I was even talking about. Another owner had the original installation instructions which showed cooling the manifold as part of the antifreeze circuit but actually used raw water. Like most of them I saw.

Sorry for any drift, but Paul, and the rest of us who may not be gurus, need to understand the difference of the two circuits through various engine components starting with the heat exchangers. I think Paul is working very hard at understanding his boat and he is getting a lot of good help here. The circuits get confusing when valves, thermostats, bypasses, and bleeds for potential airlocks get involved. Carry on.
It’s very common for the exhaust manifold to be antifreeze cooled. The raw water is introduced after the manifold at the riser.
It would be a shame to use raw water for the whole thing, it would have a short replacement interval.
 
the u hose is tapped to the fresh water pump inlet. it seems like the coolant flows from both the expansion tank and the exhaust manifold through the pump to the engine, then through the t stat housing and bypass to the heat exchanger.

View attachment 161629
It makes sense that the exhaust manifold would be in the bypass loop. It could overheat pretty quickly if there was no flow. The engine itself can have no flow for quite some time before it becomes a problem.
 
Re your post #29. YES, it is time to change that fitting. That crustiness is SALT left by the seawater evaporation. THere should NOT be any of that crustiness.
Use a thread sealer , a good one such as Rectorseal #5 , or similar. There are other good ones.

Allowing damage to the fitting also allows damage to the threaded port that the fitting resides in.

Replace that fitting.
 
I know little of the particulars of the routing of the input/outputs of the coolant pump on a Lehman, (that's 4 "of's," a modern day TF record!) but from what I see, the output of (now 5!) the pump is split.

First, to me the only input to the coolant pump appears to occur through the bulge in the block that is directly connected to the expansion tank at the 12 O'clock position in your latest picture of the pump. What else would this expansion tank connection be used for?

The pump's outputs, of which there appears to be two, occur at 2:00 O'clock where this assumed bypass is connected and at 5 O'clock where no hose seems to be connected and leads to who knows where?

Maybe I'm wrong as I have never studied a Lehman before.

Where are the Lehman guys?
 
That zinc is going to break as already suggested and it WILL CAUSE TROUBLE for you to remove it if it breaks.

Zincs of this nature need a dedicated schedule for changeouts before they corrode to badly.

Start with monthly. If still good then go to two months. If still good then three months. If the zinc is corroded at substantially at any point that should tell you to change that zinc at that interval.

DO NOT JUST GUESS about the interval.

For example I have two zincs in my heat exchangers. One little one in my gear cooler which get changed about every two months.
THe other several times the size of the above one needs a change at about the three to 4 month intervals.

But I learned those intervals by doing the above. Yours are likely different.
 
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That zinc is going to break as already suggested and it WILL CAUSE TROUBLE for you to remove it if it breaks.

Zincs of this nature need a dedicated schedule for changeouts before they corrode to badly.

Start with monthly. If still good then go to two months. If still good then three months. If the zinc is corroded at substantially at any point that should tell you to change that zinc at that interval.

DO NOT JUST GUESS about the interval.

For example I have two zincs in my heat exchangers. One little one in my gear cooler which get changed about every two months.
THe other several times the size of the above one needs a change at about the three to 4 month intervals.

But I learned those intervals by doing the above. Yours are likely different.
Thanks.
the zincs on the engine and genny are over a year now. I'll buy some spares.
 
This is a simplified plot of the fresh water circuit on page A21 of the manual. The t stat should be where the yellow cross is. When the water temp is low and the t stat is closed, how does the fresh water complete the loop?

View attachment 161510

This is a simplified plot of the fresh water circuit on page A21 of the manual. The t stat should be where the yellow cross is. When the water temp is low and the t stat is closed, how does the fresh water complete the loop?

View attachment 161510
Back to the coolant circuit discussion:
Paulga - are you sure that the thermostat is located where you marked the yellow X?
Could you take a photo like the one in Post 27 but more to the right (starboard)? Also a photo looking at the stbd front side of the engine/header tank.
 
Back to the coolant circuit discussion:
Paulga - are you sure that the thermostat is located where you marked the yellow X?
Could you take a photo like the one in Post 27 but more to the right (starboard)? Also a photo looking at the stbd front side of the engine/header tank.
earlier I was told that the thermostat is underneath the coolant reservoir and is accessed by removing the tank

1737652128153.jpeg


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Have you contacted Brian at American Diesel ? He is a wealth of FACTS because his father was the Designer of the Marinized Ford Lehman engines.
As far as an "adaptor" for a vacuum to suck out any debris in the Heat exchanger ? You have to have some common sense............Sorry
 
earlier I was told that the thermostat is underneath the coolant reservoir and is accessed by removing the tank



View attachment 161636
Re the thermostat location, I agree - it is almost certainly in the bulge off the front off the cylinder head. Bulge clearly visible just above the water pump pulley in your lower photo.

As for how the circuit works during warmup, I continue to be puzzled. I have made a sketch of how the circuit appears to be (omitting the air bleed line which is not relevant to the cooling function).

It would seem that all flow stops when the thermostat is closed - weird! However, in practice, many thermostats have a bleed hole so that some coolant always flows.

The purpose of the "U-hose" is unclear. Is it possible that there is a flow passage internal to the header tank that directs flow from underneath the thermostat to the U-hose port? Some thermostats are actually "diverter" valves that do not simply shut off a the flow. I wonder if you have a thermostat like this.
IMG_0387.jpg
 
I know little of the particulars of the routing of the input/outputs of the coolant pump on a Lehman, (that's 4 "of's," a modern day TF record!) but from what I see, the output of (now 5!) the pump is split.

First, to me the only input to the coolant pump appears to occur through the bulge in the block that is directly connected to the expansion tank at the 12 O'clock position in your latest picture of the pump. What else would this expansion tank connection be used for?

The pump's outputs, of which there appears to be two, occur at 2:00 O'clock where this assumed bypass is connected and at 5 O'clock where no hose seems to be connected and leads to who knows where?

Maybe I'm wrong as I have never studied a Lehman before.

Where are the Lehman guys?

This is a simplified plot.
the pump pumps water from the exhaust manifold into the engine block, then into the header tank via the t stat in the bulge. it says the block is the output side of the pump, and the manifold is the input.

1737688396955.png
 
Re the thermostat location, I agree - it is almost certainly in the bulge off the front off the cylinder head. Bulge clearly visible just above the water pump pulley in your lower photo.

As for how the circuit works during warmup, I continue to be puzzled. I have made a sketch of how the circuit appears to be (omitting the air bleed line which is not relevant to the cooling function).

It would seem that all flow stops when the thermostat is closed - weird! However, in practice, many thermostats have a bleed hole so that some coolant always flows.

The purpose of the "U-hose" is unclear. Is it possible that there is a flow passage internal to the header tank that directs flow from underneath the thermostat to the U-hose port? Some thermostats are actually "diverter" valves that do not simply shut off a the flow. I wonder if you have a thermostat like this.View attachment 161640
Thanks for the drawing.
It looks like only the factory has the insight to how the U hose works.
I will reach out to the manufacturer next time.

IMG20250120231704.jpg
 
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This is a Lehman 120 video, same location for thermostat.
If you look at the photo of the front, look at the coolant pump, it has a hose nipple going downwards with no hose. From there on the 120 it went to where your 'U' hose starts at manifold end. The 135 did an elimination of that hose because it went around the fan belt and had to be removed. In the video you can see the mod made was to cut the hose, insert a nipple to join the two parts so the top half can be taken off .

Can you update on the leaking heat exchanger, you were going to test where the leak was coming from. Also this thread started with a radiator valve facing up on the manifold, is that replaced?
 
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This is a Lehman 120 video, same location for thermostat.
If you look at the photo of the front, look at the coolant pump, it has a hose nippl going downwards with no hose. From there on the 120 it went to where your 'U' hose starts at manifold end. The 135 did an elimination of that hose because iy went around the fan belt and had to be removed. In the video you can see the mod made was to cut the hose, insert a nipple to join the two parts so the top half can be taken off .

Can you update on the leaking heat exchanger, you were going to test where the leak was coming from. Also this thread started with a radiator valve facing up on the manifold, is that replaced?
Thanks for the video.
cheerful music, beautiful life.
on the leaking westerbeke heat exchanger, it was not yet conclusive. see post #58. I'll inspect it this tomorrow.
 
This is a petcock on the t stat housing on a Westerbeke genny -- BCD6.0KW. it looks like a pipe plug installed on a bushing with some thread sealant.
Does this valve open and close like a ball value that usually is quarter turn? for comparison, I have attached a picture of a needle valve on a compression fitting

View attachment 161196



View attachment 161199
a distributor has confirmed the petcock part number is 11471. But the hex base in the photo of 11471 appears to have a sealed end, instead of a through passage. This is confusing.

View attachment 161198
It actually works like a globe valve (if that's any help) but this is not very relevant to it's use. The center portion (with the wing handle) is left hand threaded. Turning it CCW will open the valve to atmosphere. This is to vent air out of the cooling system. You can see the flat portion of the stem at the very bottom of the valve body. As you turn CCW that flat part (globe) moves away from the valve body and opens the valve.
 
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