Coolant recovery

I have a cat 3208 n.a..

*Some previous owner had crimped off the little tube that comes out the side of the expansion tank neck*just under the radiator cap. I was able to un crimp the tube and I have attached a hose that I have run to a gallon jug.
*The question is. Will a gallon be enough?
Not sure how much coolant it will put out once it gets warm.

SD

The coolant level in your expansion tank is probably down a little when cold and expands to brim full when at operating temp. I would expect little or no coolant to appear in your gallon jug as the engine warms up. A quart container should be adequate as a permanent catch-bottle. Fill your expansion tank to the brim, put a little coolant in the bottle, and check that the end of the hose dips below the surface of the coolant.

Gotcha. I'll Do it.

SD

SD, Actually your FW tank should be about a 1/2 inch from full. You should then loose very little coolant, if at all unless the engine runs hot. We put in the FW recovery kit from American Diesel so it operates like any other engine now. Chuck

Shoalwaters wrote:

The coolant level in your expansion tank is probably down a little when cold and expands to brim full when at operating temp. I would expect little or no coolant to appear in your gallon jug as the engine warms up. A quart container should be adequate as a permanent catch-bottle. Fill your expansion tank to the brim, put a little coolant in the bottle, and check that the end of the hose dips below the surface of the coolant.

Click to expand...

If you do this, and like in your car, you want the excess pushed out to be sucked back in from the overflow bottle when cool, you would need to change the cap to one of the correct pressure relief with the right sort of valve in it so it will suck it back.

*

There is a difference in radiator caps , the ones that let coolant return are different.

IT is very worthwhile to change EVERY coolant system to the recovery style.

The system will eventually purge all the air in the coolant , making the cooling system about 25% more efficient.

That's why there in cars , 25% smaller radiator to provide.

In the case of the FL120 it's not only the cap that needs to be changed to convert the system to an automotive-type recovery system. The neck in the filler of the header tank also needs to be changed. American Diesel sells a kit to do all this which includes instructions on how to (carefully) cut out the original neck insert and install the new one.

Good point about the special cap Peter B.

My Phasor genset was originally installed without a catch-bottle - just a little stub of pipe below the header tank cap. There were no drips, but I wanted to install an catch-bottle anyway. I contacted Phasor who said "Fit tube and bottle and away you go". I did so, but I don't see any activity in the catch-bottle. How can I tell if the cap is the right type?

Marin's observation about the length of the Lehman 120's filler neck has got me thinking. Is a special cap the only thing I need, or is the length of the filler neck critical too? If not, why not?

Mike,
A recovery system will have a radiator cap that has a small center brass "checkvalve". Whenthe system is under pressure it pushes against this round brass center valve. When the system cools down it will actually create a vacuum and draw coolant from the reservoir. It is important that the 2 sealing areas in the neck are clean. The same goes for the two ares of the cap that seal

I different cap, no matter what type you try to use, will not recapture water as both Marin and myself have said, the filler neck needs to be changed on the Ford Lehman. America Diesel sells the kit including a new cap since the old cap will not fit on the replacement neck. Chuck

Shoalwaters wrote:Marin's observation about the length of the Lehman 120's filler neck has got me thinking. Is a special cap the only thing I need, or is the length of the filler neck critical too? If not, why not?

Click to expand...

it's not the length of the neck on the FL120 that needs to be changed.* It's the insert that's inside it that needs to be changed.* The stock insert does not allow coolant to be pulled back into the tank.* So both the neck insert and the cap need to be changed to allow coolant to be drawn back into the tank as the coolant cools down.* The overall neck length remains the same.

*

Marin, correct me if I'm wrong, but I seem to remember you saying once you got this kit for both, but have not yet got round, 10 yrs later, to fitting same. If so I can understand it, as like someone else said before, if you don't overfill the header tank, the same gap between the coolant surface and the cap seems to stay pretty constant, and I find I add a smidgeon of coolant about once a season. I would not bother with the conversion myself as a result, and I can confirm when the boat was re-painted recently and the duckboard was off, we found behind it the hull stamp reading CHB 1 - 1975 plus several numbers and letters I didn't understand what they meant. The point being it's 'just worked', for 35 yrs, so why fix it?.

Here's an explanation of HINs and how to interpret them:
http://www.boatsafe.com/nauticalknowhow/hin.html

Peter B wrote:

If so I can understand it, as like someone else said before, if you don't overfill the header tank, the same gap between the coolant surface and the cap seems to stay pretty constan

Click to expand...

The danger in an FL120 is if the coolant level in the tank gets low enough to allow an air pocket to form in the top-front of the exhaust manifold.* If that happens the heat will soar in that one spot and the manifold will be ruined in short order.* Given that these Lehman manifolds are almost impossible to get these days, I believe it's smart to make sure an air pockket doesn't form there.

We do have a recovery system in our boat, it's just not an efficient one.* I extended the overflow tubes from the header tanks so they dump into small bottles down in the engine drip pans.* I periodically dump this fluid from the bottles back into the header tanks.

I make it a practice to check the coolant level in the tank before every start---- as you say there can be an air gap between the level and the bottom of the neck and as long as this level does not drop it will be sufficient to prevent the formation of an air pocket in the exhaust manifold.* I also crack the bleed valve at the front of the manifold before most starts to ensure that no air has gathered there.

What you say you do sounds fine to me as long as the coolant level in the tank is not allowed to drop to the point where an air pocket can form in the exhaust manifold.* I* prefer to minimize the chances of this happening by using my "poor man's" recovery system until the day comes I get around to installing the proper ones.

*

Keith,
That is a great link. Turns out we are hull 65 for Present Yachts. PYZ000650683.
Didn't you post a link once that let you use the Documentation nber to be able to tell who the owner is? Sorry to hijack the thread.

http://www.st.nmfs.noaa.gov/st1/CoastGuard/index.html

You can search by name or number.

Got it. Thanks!

So, do I need a retro fit cap*for the cat 3208?
*
SD

Hi SD,

If you want to go with a coolant recovery bottle you will need to get a cap specifically for COOLANT RECOVERY SYSTEMS. If you don't, the existing cap will allow coolant to spit out to the bottle upon heatup, but upon cooldown it will not pull the coolant back.

Cat should have a RECOVERY type cap. If not then go to the nearest auto/truck parts supply house , take the existing cap with you and go through the catalogues. Stant or Gates should have a match that is suitable.

This is worth doing.

I don't have a coolant recovery system. My exhaust manifold dos'nt have the heat exchanger in it as it's on the bulkhead so the exhaust manifold has nothing in the upper half (or more) so it's nearly full of coolant. I run it about 1 1/4" below the cap so there's plenty of air space for expansion and the extra volume of coolant. I have a "Murphy Switch" on the side of the manifold so long before the coolant level gets low enough to cause overheating the alarm sounds. I really like this setup.

"I run it about 1 1/4" below the cap so there's plenty of air space for expansion ."

A header tank or the coolant recovery setup would give 25% better cooling for about $20.

The usual reason extra cooling is needed is the aging of coolant.

The modern diesels with exposed to the coolant cylinders (instead of pressed into the cast block, or as in a throwaway 3208 ) require anti freez to control cylinder erosion from cavitation.

The knocking sound diesels make frequently comes from the cylinder it self ringing like a bell.

The coolant in contact does not stay in contact with the cylinder and cavitation pitting and erosion results.

The anti freez folks solution is an addative that coats the cylinder walls , so the "green slyme" gets eaten by cavitation , not the cylinder wall.

Thats one of the differences between diesel antifreez and car stuff like Prestone.

Unfortuniatly the green slyme builds up on the entire cooling system inside the engine , and heat exchanger.

The MFG suggests a 2 part cleaning and rinse every 2 years ,
Not doing it can compromise the system enough so extra cooling ability is useful.

Good insurance for only $20. and a half hour of install, time.

"A header tank or the coolant recovery setup would give 25% better cooling for about $20."

I don't see how and you give no reason whatsoever. In my case the exhaust manifold is the "header tank". Like old cars w a large header tank on the top of the radiator. The advantage of the coolant recovery system as I recall is to limit oxygen in the coolant system and thereby reduce corrosion.


Marin,
If your Lehman cooling system is close to sucking air and causing "air pocket" problems when operated normally as Peter B describes you need to correct the bad design. A Murphy Switch and/or a coolant recovery system would be a high priority on such an engine. You check it every time you start??? Sounds like you're quite concerned. And when you install the recovery tank make sure it's above the cooling system (radiator) cap. Many of those things have trouble "sucking" coolant back UP to the header cap. So basically the higher the better.

nomadwilly wrote:"And when you install the recovery tank make sure it's above the cooling system (radiator) cap. Many of those things have trouble "sucking" coolant back UP to the header cap. So basically the higher the better."

Click to expand...

Good advice although I know you can't accomplish this on all boats.
My boat was designed and built with this thought in mind and my coolant recovery
tank resides under the salon settee. Overflow rises to the recovery tank and gravity
feeds back through the cap as the engine cools. The last time, in the past 4 years,
that I added coolant to the systrem was about 2.5 years ago when I replaced it.
When the engine is cold, the coolant recovery bottle has about 2 inches of coolant
in it.

The first photo shows a small hatch along side the salon settee.
The second photo shows the hatch closed
The third photo shows the hatch open, right above the coolant tank fill. (I know, I
know...anal as hell)




*

nomadwilly wrote:

Marin,
If your Lehman cooling system is close to sucking air and causing "air pocket" problems when operated normally as Peter B describes you need to correct the bad design. .....And when you install the recovery tank make sure it's above the cooling system (radiator) cap. Many of those things have trouble "sucking" coolant back UP to the header cap. So basically the higher the better.

Click to expand...

No, I think it's a long way from sucking air.* The header tank blows out a small amount of coolant when it's full and then it doesn't blow out any more after that.* I just like to keep things topped off is all.

Interestingly enough, Brian and Bob Smith at American Diesel have told me that they recommend that the recovery bottle be mounted very low in the engine room, considerably below the level of the header tank.* I don't believe this idea is the best and when I get around to mounting our tanks I'm going to mount them the same way they have been in every vehicle I have owned---- at the same height as the coolant tank so that the nomal "full" level in the tank is even with the 1/3 full level of the recovery bottle.

*

"I don't see how and you give no reason whatsoever."

Air is an insulator, removing the air and the system gets about 25% more efficient.

The modern recovery system does work.

FF,I don't think there's air in the system unless the coolant level is quite low. Air rises and should be at the top of the headed tank. If the flow through the header tank became strong enough of course air would be mixed in but I can't imagine engineers designing a system that would pump itself up w 25% air???


Marin,
Those American Diesel guys are (as you suspect) dead wrong. You need to get out more *....find some better sources of information. I recomend Harbor Marine in Everett or Gallery Marine in Seattle. Also the shop on Nickerson (where Norm Dibble used to work) I think is good. Nix on Stewarts in Ballard. Obviously level w the top of the header tank works fine as thats where it is on cars and there's lots of cars. But higher does work even better. In theory lower should work fine too but in practice it does not.


Walt,
All I can see of the salon settee is the cushions. Sounds like a good place though. As long as there's not much horizontal run of the tube.

nomadwilly wrote:


Marin,
Those American Diesel guys are (as you suspect) dead wrong. You need to get out more *....find some better sources of information...


*

Click to expand...

Eric--- The Smiths at American Diesel know a lot of stuff about Lehmans, which is logical since Bob Smith did much of the original marinization work on the Ford of England base engine when he worked at Lehman Bros.* But they have some "practices" that I don't adhere to or believe are the best practices.* Their coolant recovery bottle placement recommendation is one of them.

I tend to use my own logic, the experience I've had with other kinds of engines over the years, and advice from our diesel shop and people I know in the marine engine manufacturing business in addition to advice from Bob Smith.* There is also a lot of first-hand experience information about these engines on the Grand Banks owners forum as most of the older GBs have Lehman engines in them.* So as you say, there's a lot of information out there and I agree that taking advantage of as much of it as possible is a good idea.

In our boat the tops of the header tanks on the engines are right under the main cabin sole.* So it's not possible to mount the bottles higher than the header tanks.* But it is possible to mount them even with them.* I see that as a much better position than somewhere down low as AD recommends.

*

I'm missing something in the placement of the coolant recovery bottle debate.* I thought the coolant was pulled back into the header tank by the vacuum caused by the contraction of the liquid as it cooled.* So it would not matter at all where the recovery bottle was located.

What?

BaltimoreLurker wrote:

I thought the coolant was pulled back into the header tank by the vacuum caused by the contraction of the liquid as it cooled.* So it would not matter at all where the recovery bottle was located.

Click to expand...

In theory you are correct.* However, from what I've been told the easier you make it for the coolant to flow back into the system the better because the power of the vacuum pulling the fluid back can vary due to factors like cap seal, hose to tank seals, etc.

If the bottle is mounted above or even with the header tank, you actually don't need any vacuum at all to return the coolant to the tank.* In some of my vehicles, for example, there is no conventional radiator cap.* When changing the coolant there is a small plug that you remove from the top of the radiator and then you fill the system through the expansion tank.* Coolant flows by gravity into the radiator until the "full" mark is reached on the expansion tank at which point there is the correct level of coolant in the radiator.

So while American Diesel's recommendation to mount the recovery bottle low in the engine room is okay in theory, I don't believe it takes into account what may be reality if a cap or hose seal becomes a bit "iffy."

*

Marin wrote:In theory you are correct.* However, from what I've been told the easier you make it for the coolant to flow back into the system the better because the power of the vacuum pulling the fluid back can vary due to factors like cap seal, hose to tank seals, etc.

Click to expand...

That sounds reasonable.* Redundancy - if the vacuum fails, maybe gravity will work.

I have the same issue as you though, the tank us right up against the underside of the access hatch.

*