closed cooling Crusader 3.8 loosing coolant-gctid817000

[mergansergbyc]

Looooooooooong story. 4 yrs ago hired experienced marine mechanic to resolve my 1984 Crusader 3.8's loosing coolant in my 32' 3270. Experienced problem after I bought boat and he told me need to remove manifolds, hone the surfaces and install new gaskets etc. In the process did compression test and wound up rebuilding both engines (skipping details.) He did the honing of surfaces and new gaskets and other items required. Well, here we are and am STILL loosing coolant. Not in the oil pan nor in the bilge so has to be going out the exhaust. Had the heat exchangers cleaned and pressure tested. Small leak fixed. Both engines loosing coolant. Stbd engine about twice amount of port engine. Is it possible mechanic installed the "diverters" incorrectly?

Has anyone converted their closed cooling system to raw water? I can't go anywhere this way. After 2 hours stbd engine looses about a quart and port engine about half that. HELP please.

[heedrix]

HEat exchanger might have cracks in it.

[SuperiorDiver]

One of the engines on my boat was loosing coolant. When I removed the raw water hose to winterise, green water came out. I removed the heat exchanger, sealed the connections and filled the unit with water. Putting air into the coolant circuit showed bubbles in the raw water circuit. Replaced the heat exchanger and no issues since.

[Sportscar]

It would seem new heat exchangers and a new better mechanic might be the solution. Certainly changing the system to raw water cooling is not only not the answer but a bad idea.

[builderdude]

This sounds like it's a full closed cooling system incorporating the exhaust in the closed cooling loop. If the heat exchangers have been pressure tested and in fact have no issues I'd be looking at possible cracks in the exhaust components. Small hairline crack often don't open up until things warm up. I'd warm the engines then do a leak down of sorts on the cooling system, you might hear some leakage through the exhaust.

I'd also agree, do not convert to raw water cooling.

[mergansergbyc]

any body have any idea where one would get 2 pair of exhaust manifolds for Crusader 3.8's? Scary thought that that is what is required. Will do the pressure test. Can I put the tester on before starting the engine and observe as it warms up???

[hfxjack]

Take them to an automotive rad shop they can test and repair

[builderdude]

My thought on pressure testing would be more of a leak down test on the cooling system. Your loosing a lot of coolant, if there's no evidence of coolant in the engine oil then it's either spent out with the exhaust or is being burned up in the cylinders. With that kind of volume being introduced into the cylinders by either a faulty head gasket or cracks in the exhaust I'd think you'd have some hydro locking by now. You sure the exchangers are not the issue? I'd warm the engine(s) pull the plugs to look for signs of coolant then pressurize the closed cooling system and listen for where the pressure is being lost.

[mergansergbyc]

did the leak down test on system. When cold no loss of pressure. Ran engine for 10 minutes then redid the test. Lost pressure quite readily. OUCH! As the boat lives in the Great Lakes with no salt water, eliminating the closed cooling not as troublesome as salt water (my opinion). Don't know if feasible to go to raw water completely is any less costly than resolving current problem. Need to find the problem first. Any ideas???????

[builderdude]

You'll want to pinpoint where that coolant is being lost and repair it regardless weather you choose to eliminate your closed cooled system. You said the engines were rebuilt, were the head bolts ever re torqued after the first run?

[mmichellich]

External to the block what parts have antifreeze in them, ie the exhaust manifolds, the risers, heat exchangers, what others might have antifreeze in them. Now you have a stsrting list. Do you see any antifreeze in the bilge? Have you ruled out gaskets in those parts?

[mergansergbyc]

what started this whole fiasco 4 years ago was loosing coolant. Mechanic stated need to remove exhaust, true up the mating surfaces and put in new gaskets and other paraphenalia. When I bought the boat it was loosing coolant. After mechanic told me what was needed to stop loss I used Solder Seal in each system. "Solved" the problem for the next 9 years. Started again 4 years ago so decided time to bite the bullet and do the recommended resurfacing etc. That is why I am wondering if it is possible that the "diverters" are in incorrectly or some other part of that process. Can find no instructions on the reassembly of the exhaust manifolds after the planing of the mating surfaces and reassembly. I hope it is that simple and not requiring new manifolds, if they are even available. Does anyone have the assembly instructions?

[builderdude]

If your exhaust manifolds are included in the closed cooled loop there would be a block off plate between the exhaust manifold and the exhaust elbow. If the block off was not used and an open gasket was installed then that's where you'd loose tons of coolant.

Maybe you could post a pic of your engine, exhaust manifolds/elbows and related plumbing.

[mergansergbyc]

regarding the blockoff plate, is it possible it could be put in incorrectly such that only some of the coolant is lost? If it was completely left out there wouldnt be enough coolant in the system to run in the short term vs a couple of hours. There were so many pieces to the kit I got from Crusader for the manifolds it was a jigsaw puzzle. I was glad an experienced marine mechanic was doing the work. As both engines are loosing coolant thinking something was put in backward or upside down so only a small amount was being lost. Just thinking.

[ALASKAN_ADVENTURER]

If you convert to raw water system you will burn lake mi water in your motor instead of antifreeze

Ex manafolds, head gaskets ,intake gaskets, warped heads, cracked blocks, cracked heads