coolant loss in my crusader

[Beckytek]

A few weeks ago while cruising around the bay, my starboard engine overheated. I brought the boat back to the slip on one engine. The coolant level was very low and I added 2 1/2 gallons. I had the yard check to see where the leak was. They tested the heat exchanger and that was good. They found the gaskets on the manifold were mushy and they replaced them. I took it out for an hour and it leaked a gallon again.
The oil level is good and I can't see any obvious leaks anywhere. The engine runs great and gets up to full RPM's. Where else should we look? Any suggestions are welcome. Ron

 

[Boatsb]

If the manifolds and risers are 5 years or older replace them. If you dont you may do more damage and even hydrolock. If it overhea t ed there could also be a head or head gasket issue.

 

[Beckytek]

The risers were replaced this spring. The manifolds were replaced 6 years ago.

 

[Maynard Rupp]

It sure sounds like a corroded hole in the heat exchanger between the antifreeze side and the sea water side. You are very lucky so far. If it rotted from sea water to exhaust you would have destroyed that engine. I had an outfit on Long Island make new risers with elbows from copper nickel. This is the same stuff your heat exchangers are made of. I paid $3200 for all 4 of them. They work great and will last forever. PM me if you want the contact.

 

[Boatsb]

The risers were replaced this spring. The manifolds were replaced 6 years ago.

Manifolds go bad. I always replace both at the same time.

 

[Maynard Rupp]

Manifolds on Crusaders never go bad as they are not exposed to sea water...Alas, I was wrong in my last post about your risers and elbows.. While Crusader's manifolds see no sea water, The risers and elbows see no anti freeze, only sea water. The only place where both sea water and anti freeze are present is the heat exchangers. These are the 5" or so round tubes that lay across the engine just behind the intake manifold. Somehow the 2 liquids are getting together inside that one. The end caps are removable if that would help. I would disconnect all hoses, block off all but one opening on the seawater side, and blow with your mouth in the one remaining hole. If it is leaking internally you will lose pressure. Oh yes, don't forget to remove the radiator cap.

The only other possibility is a failed gasket between the manifold and the riser. This would allow antifreeze to flow from the manifold to the riser then out through the exhaust system. That is very possible.

 

[SeaEric]

The only other possibility is a failed gasket between the manifold and the riser. This would allow antifreeze to flow from the manifold to the riser then out through the exhaust system. That is very possible.

+1 on that.

 

[Beckytek]

I just talked to the mechanic at the yard. He said the problem was when they installed the new risers they used the wrong gasket between the riser and manifold on the starboard engine. The port engine is ok. How they did that I don't know. He said the manufacturers changed the gaskets and they didn't know about the new ones. Something about a metal plate. Gives me a lot of confidence, (not).

Maynard you are correct about the original manifolds. When they replaced the original manifolds the old ones were like new after 18 years of use. The only reason they were changed was because I couldn't buy the original risers for this engine (12"). They stopped making them. So they installed mercruiser manifolds and risers instead. I wish I knew about making new ones as you did. Ron

 

[Boatsb]

There has been 2 types of gaskets for years. Mercruser makes both fresh and saltwater .

 

[dsharp]

One style has the water passages cut out if the engine is raw water cooled and the other style has a stainless plate that blocks off the passages between the manifold and the riser since the manifold is fresh water cooled and the riser is raw water cooled. Pretty basic stuff, I would maybe look for a different mechanic.

 

[Maynard Rupp]

I just talked to the mechanic at the yard. He said the problem was when they installed the new risers they used the wrong gasket between the riser and manifold on the starboard engine. The port engine is ok. How they did that I don't know. He said the manufacturers changed the gaskets and they didn't know about the new ones. Something about a metal plate. Gives me a lot of confidence, (not).

Maynard you are correct about the original manifolds. When they replaced the original manifolds the old ones were like new after 18 years of use. The only reason they were changed was because I couldn't buy the original risers for this engine (12"). They stopped making them. So they installed mercruiser manifolds and risers instead. I wish I knew about making new ones as you did. Ron

I had the same 12"risers and yes, they are no longer available. I had my risers and elbows duplicated in copper nickel for $800 each. This is a permanent fix and I no longer need to be concerned about those miserable cast iron parts corroding through.

 

[workingonadream]

that's a lot of antifreeze for a bad gasket were you blowing more smoke out of that engine than the other, it should have been noticeable. also how did the yard check the exchanger, if they only used a pressure tester where the cap goes they likely checked the whole system. I just had the same problem with a friends crusader where it was his exchanger that went bad. all the symptoms you have, he had. the way we checked his exchanger was to take off both raw water hoses plug one of them and then we took off a fresh water hose. we then found a nozzle that fit snug into the raw water hose and shot water thru it, when we did ,we had water coming out of the fresh water side which should not have happened if the exchanger was good. it cost him approx. $900 for a new one and he was good to go. good luck

 

[roundIII]

Same result as workingonadream said. It was the HE leaking.

R

 

[Beckytek]

The risers were changed at the beginning of the season. I used the boat all summer without any problem until 3 weeks ago. It must have been a very slow leak until recently. The last time I took it out it leaked a gallon in one hour at planing speed. I asked the the yard boss how they could use the correct gaskets for one engine and not the other and he said, "I don't know". Ron

I didn't notice any smoke at the exhaust and I don't know how they checked the exchanger.

 

[workingonadream]

If there is no coolant in your oil or tranny cooler and you do not see any increase in steam coming from you exhaust as compared to the other engine, I would definitely test the exchanger the way I said in my earlier post. You should have a metal blocker gasket between your riser and manifold which is used to prevent the mixing of the raw water with the coolant, yours is new, and I have a hard time believing that is your problem. I would be suspect of the yard mechanic especially if you did the risers on both engines at the same time. One would think the parts all came from the same place at the same time. Remember to ask him how he pressurized the system. If he used a pressure tester where the cap goes, all that will tell him is that you are losing pressure somewhere in the system. it will not isolate where. good luck.

 

[Beckytek]

I'll check with him the next time at boat.