Losing coolant 4.3L V6 volvo penta

MRWood

MRWood

Well-Known Member
I've been losing coolant from my 4.3L V6 motor. I'm not sure where it is going. There is no sign of it in the bilge and oil looks clean and normal level.
Could it be a heat exchanger issue? Could coolant leak into the raw water and discharge through the risers. It's the only thing I can think of. How would one test for that?
FYI...I am drawing up plans in my head for a pod project on my boat but need to get through the season without too much expense. Almost there lol.
 
Most of the time when heat exchangers leak its the hot that leaks into the cold side. This is because of the expansion and pressure the hot side gets when the engine is at temp. You can have the heat exchanger tested. If your on the mainland I can recommend a place. They are in port moody. Think they are called Port Moody Auto & Air.
 
ship happens said:
Most of the time when heat exchangers leak its the hot that leaks into the cold side. This is because of the expansion and pressure the hot side gets when the engine is at temp. You can have the heat exchanger tested. If your on the mainland I can recommend a place. They are in port moody. Think they are called Port Moody Auto & Air.
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Thanks SH. I’m in Nanoose on the Island.
So what I explained sounds like it’s likely a heat exchanger issue to you?
The heat exchanger is old, likely as old as the boat, 1992 😊.
1724354492736.jpeg
 
i had that problem on an inboard before and was solved with a new rad cap which is by far the best possible solution.
 
I have the same engine as you and had the same problem 2 years ago. I got the heat exchanger pressure tested and it was full of pinholes and some of the tubes had already been soldered shut. Ended up getting a new one from Seakamp in washington. it was basically the exact same one it was simple plug and play.
 
MRWood said:
Was there coolant leaking out of the rad cap?
I don’t see any evidence of that on mine.
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no evidence of leak at the cap, i topped it up every use for a year or so then put a new cap on the exchanger and my coolant lose ended. like i said best case scenario but worth a cap
 
MRWood said:
Thanks SH. I’m in Nanoose on the Island.
So what I explained sounds like it’s likely a heat exchanger issue to you?
The heat exchanger is old, likely as old as the boat, 1992 😊.
View attachment 109695
Click to expand...


It is very common on old equipment. Usually it will be one or a few tubes that leak. that pipe plug on the top there is a zinc. maintianing that zinc helps, however heat exchangers do fail over time. if you take the end caps off you will see how its built. the tubes are pressed in. Some tubes get holes in them but most of the time they leak at the seams where the tubes are pressed in. The only repair is to solder the tube closed, deleting the tube entirely. In which case will not effect performace. Your allowed to delete a few tubes.

Most likely its the heat exhchanger if your not finding coolant in the bilge. Only other thing it could be is the head gasket. In which case normally you would have other engine symptoms. Its easy to have the heat exchanger tested
 
ship happens said:
It is very common on old equipment. Usually it will be one or a few tubes that leak. that pipe plug on the top there is a zinc. maintianing that zinc helps, however heat exchangers do fail over time. if you take the end caps off you will see how its built. the tubes are pressed in. Some tubes get holes in them but most of the time they leak at the seams where the tubes are pressed in. The only repair is to solder the tube closed, deleting the tube entirely. In which case will not effect performace. Your allowed to delete a few tubes.
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All noted with thanks.
Can you add some of that rad leak solution that plugs holes in a rad?
 
MRWood said:
All noted with thanks.
Can you add some of that rad leak solution that plugs holes in a rad?
Click to expand...
Negative. The only way to repair a heat exchanger is to figure out which tube is leaking and delete it. The tubes are basically inserted into the plates and then flared and that creates the seal. There are probly shops that can replace tubes, but I dont know of any.
 
Mine did the same when I had the inboard. I ended up replacing exchanger.

Mine was internal and no shop wanted to fix it. Even rad repair guys weren't interested. They just said get a new one.

Seakamp was crazy expensive.....I was lucky one of the rad shops had a used exchanger.
 
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SpringVelocity said:
Mine did the same when I had the inboard. I ended up replacing exchanger.

Mine was internal and no shop wanted to fix it. Even rad repair guys weren't interested. They just said get a new one.

Seakamp was crazy expensive.....I was lucky one of the rad shops had a used exchanger.
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And hence the….. “I am drawing up plans in my head for a pod project on my boat but need to get through the season without too much expense. Almost there lol.”
It’s time for new risers as well as it’s been 5 years. Probably close to 2 grand for them. heat exchanger another fifteen hundred or so. It adds up and that dough could go towards the pod and new motors.
 
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Yep never had a regret.

Yeah that exchanger was a ***** for me. Stupid thing broke middle of nowhere in Port Hardy. We had to use waterbottles to keep filling the exchanger to get home.

Oh and there was also time stuck also middle of nowhere in Barkley Sound. Dead in water because of one grounding cable. The stories were endless!

Another beaut was when the starter bolt broke and had to yard out engine to fix. When that thing left it was good riddance honestly.

The only happy people were the mechanics as I was spending big money just to keep running each season. I fixed a lot of it myself but some things I needed them for.

Just yard that thing out and be done with it.
 
Try JB Radiators in Campbell River, I would call them and ask if they will do it. Jordan 250-287-7003
Have used them for Marine work in the past for tube and nest repairs
 
MRWood said:
And hence the….. “I am drawing up plans in my head for a pod project on my boat but need to get through the season without too much expense. Almost there lol.”
It’s time for new risers as well as it’s been 5 years. Probably close to 2 grand for them. heat exchanger another fifteen hundred or so. It adds up and that dough could go towards the pod and new motors.
Click to expand...
If you need help with boat math we are there for you during this difficult time. You probably have a perfectly good leg to sell. Couple used 200hp Suzukis sitting in port alberni for months, not sure what you would repower w but an offer might be accepted.
 
kaelc said:
If you need help with boat math we are there for you during this difficult time. You probably have a perfectly good leg to sell. Couple used 200hp Suzukis sitting in port alberni for months, not sure what you would repower w but an offer might be accepted.
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Thanks Kael. I likely do need some boat math help from someone more on top of things than I am.
I would repower with either a single 200 or 225hp and matching kicker on a pod. I was looking at the Mercs at APM and I liked 200 and 225. They are identical motors except for the extra 25hp and the extra $5,000 for the 225. Not sure why $5K extra for a tweek to the brain of the motor.
 
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