Coolant running out of Exhaust - Yanmar

[Seawayva]

This summer I had my turbo rebuilt on a Yanmar 4lha - STP. After we got it back in the boat ran fine with no problems. Temperature was right and the performance was up a little. Probably put about 15 hours on the boat since.

Cut to yesterday when I took the boat out to fish. It was very foggy so I was going about 7 knots (14-1500 rpm) for about 4 minutes when the temperature gauge went from about 140 to about 200 very quickly. Cut the engine back to idle and opened the engine box and saw no obvious problems. The gauge then fell back to about 160. Turned around and idled back to the dock. On that 5 to 7 minute trip the gauge went to 180 and stopped.

Upon checking the coolant in the engine I discovered it was low. By two gallons. Filled it back up and today started the engine. Coolant is coming out of the exhaust at high idle at the dock.

Trying to isolate the cause.

Bad seal in the turbo? That is my hope (unless something less labor intensive and wallet intensive is the case) as it is the only thing that has been altered and the rebuild is under warranty.

Other thoughts?

A mechanic is going to pressure test the cooling system to verify. I assume when this is done if the turbo is bad coolant will pool or pour from it on the exhaust side?

Thanks for any help.

Matt

 

[Eslang]

This summer I had my turbo rebuilt on a Yanmar 4lha - STP. After we got it back in the boat ran fine with no problems. Temperature was right and the performance was up a little. Probably put about 15 hours on the boat since.

Cut to yesterday when I took the boat out to fish. It was very foggy so I was going about 7 knots (14-1500 rpm) for about 4 minutes when the temperature gauge went from about 140 to about 200 very quickly. Cut the engine back to idle and opened the engine box and saw no obvious problems. The gauge then fell back to about 160. Turned around and idled back to the dock. On that 5 to 7 minute trip the gauge went to 180 and stopped.

Upon checking the coolant in the engine I discovered it was low. By two gallons. Filled it back up and today started the engine. Coolant is coming out of the exhaust at high idle at the dock.

Trying to isolate the cause.

Bad seal in the turbo? That is my hope (unless something less labor intensive and wallet intensive is the case) as it is the only thing that has been altered and the rebuild is under warranty.

Other thoughts?

A mechanic is going to pressure test the cooling system to verify. I assume when this is done if the turbo is bad coolant will pool or pour from it on the exhaust side?

Thanks for any help.

Matt

head gasket?

 

[reelsportfishing]

Sounds like the turbo housing. Will have to verify with pressure test.

 

[Seawayva]

What would be the symptoms of a head gasket failure (aside from coolant from the exhaust?)? There is no water or coolant in the oil, or oil in the coolant that was in the expansion tank.

 

[Seawayva]

Sounds like the turbo housing. Will have to verify with pressure test.

So what or where is the failure? Is the turbo housing the actual "turbo" not something internal? If that even makes sense. Please excuse my ignorance, I am in the learning stage here...

 

[reelsportfishing]

The turbo charger sits inside the turbo charger housing which is cooled by antifreeze. Your wet elbow is also attatched to your turbo charger housing.

 

[Seawayva]

Okay thanks, just trying to get the terminology straight. I am hoping the mechanic can get down to the boat tomorrow to pressure test the turbo. Thanks for your help.

 

[reelsportfishing]

You have exactly the same symptons that I had. You could put a pressure test on it at the dock and it would hold. Take it for a ride, and you would loose it. The mechanic actually put dye in the coolant. We did not find it until we actually pulled the turbo out of the housing and pressure tested it. That was after a $1200 wet elbow he thought was bad. Good luck. Thankfully you caught it before it became a problem. I always carry 6 to 8 gallons of water in old antifreeze jugs just in case.

 

[captainlarry84]

Go to where man last touched. Therefore I would hone in on the turbo seals. It could also be the heat exchanger which could push the coolant out the exhaust but that is rare on Yanmars unless you did not keep your zincs up to grade. Also went heat exchangers go because the raw water pump has more pressure that the fresh water system salt water would be in your cooling system & that does not seem to be the case because your coolant was low. Exhaust elbow failures are also not uncommon on you motor and that elbow is right after the turbo.

 

[Seawayva]

I just changed the engine zincs. Boat is in fresh water and the old ones looked new, just a bit discolored.

I am thankful I keep an eye on the temp gauge. Otherwise it could have been a much worse day.

 

[samhop]

blowing things up

head gasket, heat exchanger, maybe cracked turbo housing or cracked wet exhaust manifold. im dont know yanmar but have never seen a coolant seal inside a turbo, oil seal yes.

 

[captjohn]

Could be something as simple as a heat exchanger leak. I like to start with the least expensive thing first. When you replaced the zincs, did you put the right length zincs in? On some coolers, if there too long, you can punch through the bundle, causing a leak. Worth a look.

 

[pugsley]

I just changed the engine zincs. Boat is in fresh water and the old ones looked new, just a bit discolored.

I am thankful I keep an eye on the temp gauge. Otherwise it could have been a much worse day.

if you are in fresh water that has a lot of tannic acid in it, the zincs will do no good, and the acid will eat up any metal. (a lesson learned from crabbing in fresh-ish water)

but i would lean towards having the turbo checked,

 

[Seawayva]

Could be something as simple as a heat exchanger leak. I like to start with the least expensive thing first. When you replaced the zincs, did you put the right length zincs in? On some coolers, if there too long, you can punch through the bundle, causing a leak. Worth a look.

They were the exact same as what came out. I bought a "kit" specifically for the engine.

 

[Seawayva]

if you are in fresh water that has a lot of tannic acid in it, the zincs will do no good, and the acid will eat up any metal. (a lesson learned from crabbing in fresh-ish water)

but i would lean towards having the turbo checked,

I have no idea, truthfully. I boat on the Potomac River, up by DC. After a rain there are a good amount of rubbers floating around, but I never considered tannic acid.

 

[Seawayva]

Just got back from the boat. I took the endcap off the heat exchanger and it is full of antifreeze. The mechanic happened to be there and he confirmed it. I guess the question now is whether I should get the Yanmar part at $1600 or the SeaKamp knock-off at about $800. I am inclined to spend the money for the Yanmar part. Any thought on that? Anyone had any luck with the aftermarket brand? I think it is SeaKamp.

I appreciate everyone's help.

Matt

 

[traditions]

Could it just be a O ring in the heat exchanger?Some where there is a seal to keep the coolant from the raw water.I would think it would be un likely that the core is corroded out in fresh water.

 

[Seawayva]

I am not sure as I haven't taken it off yet to closely inspect it. What I know is the end opposite the seawater pump was pink with antifreeze. The engine began its life in salt water for about 5 years and has now been in fresh for about 4.

I can't find a good diagram of what the heat exchanger looks like other than it has a bundle of tubes.

 

[samhop]

you should be able to get jest the bundle. can be id the manufacture by dimension. Yanmar is not making there own heat exchanger. pull the bundle look in the yellow paper com fish, or nati fish, you will find several manufacturers call um with bundle in hand.
your burning daylight boy.

 

[Seawayva]

Well, I have now discovered that the bundle in the heat exchanger is not removable, the heat exchanger is one piece. This, of course, means that I will need to replace the entire package. It was suggested that I could simply identify which tube(s) is bad and plug it, as long as it was not more than one or two tubes. I am not going to do that since it seems to be begging for trouble down the road.

Now I guess I need to determine if I should buy the Yanmar part (which I would imagine is not manufactured by Yanmar) or if I should get a SeaKamp aftermarket exchanger. I can get a new one for $725. The Yanmar part is $1600.

Any thoughts?