6v92 sweet smelling exhaust

[Jim saco]

The last time I used my 41c I smelled coolant coming from the star. side exhaust. I thought I had smelled it earlier in the season but my coolant level was never low. On the last 2 runs I lost about 1 gallon. My mech. came and advised on not using the boat. After waiting 2 weeks for him to get time to pull it apart I got impatient and pulled my exhaust manifolds off. I found the tell tail sign of water " white and clean" coming from my outboard rear cylinder exhaust port on the head. How much work is it to pull the head off? I called my mech. and he tells me that's the next step he also told that he can put it back together if I can't. He's saying all it takes is time and money. If I take this head off what can I expect? This is my first time doing anything major on a diesel.

[saltshaker]

Are you positive it is from the head and not the exhaust pipe? If the riser leaks it will run down to that same spot. I had the exact same problem on a 6V92. I also figured it was from the head but it turned out to be a pin hole in the exhaust riser.

[dsharp]

If it's burning antifreeze it has to be leaking in the system before it gets to the riser. It is usually better to pressure test the manifold before you start taking the engine apart. You can usually rig something up with pvc fittings and a gauge and schraeder (tire) valve. As far as difficulty, it's not really hard it just takes bigger tools and a couple of people to lift the head off. Be very careful with the head, they have have machined edges that can damage your hands pretty badly if it gets away from you.

[rsmith]

A good radiator shop should be able to press test your manifolds. I was losing water in my 12'/71's and pressurised the system cold and found the injector tubes were leaking. If you get one of the slant testers you pressurise the system your self.

[saltshaker]

If it's burning antifreeze it has to be leaking in the system before it gets to the riser. It is usually better to pressure test the manifold before you start taking the engine apart. You can usually rig something up with pvc fittings and a gauge and schraeder (tire) valve. As far as difficulty, it's not really hard it just takes bigger tools and a couple of people to lift the head off. Be very careful with the head, they have have machined edges that can damage your hands pretty badly if it gets away from you.

Not in my case. The leak was in the exhaust riser. The coolant was burning off when it hit the hot exhaust. Visible white smoke and the sweet smell of antifreeze. You might get small amounts into the cylinder that will be burned off while the engine is hot. The problem arises when the coolant leaks into the cylinder when at rest. He may have a leak that is only evident while the engine is hot and running. Mine closed up when the engine cooled down making it extremely difficult to find.

Jim I wouldn't pull the head unless you are certain that is where the leak is. Any overheating or high running temps? How many hours on them?

[Jim saco]

The manifolds look ok that's not to say that it's not the problem however they are lower than the heads. It seems that the manifolds would have to fill up for it to get into the cylinder. At least when the motor was at rest. The coolant is evident in the exhaust as soon as it fires there's not much of any smoke just a light steam and that sweet smell. The motor never ran over temp atleast it never has since I've owned it. The motors have 300 hours after an inframe was supposedly done. I've owned her for about a year now. The po had enough receipts to make me and my mech believe it had been done. I feel confident I can remove the head without damaging it However I don't want to remove it if it doesnt have to come off. If the leak was in the exhaust down stream from the head and the motor was burning it off why would I have evidence of water on the exhaust port without the motor hydro locking? I never had any sign of it laboring during start up.

[saltshaker]

My entire engine still looked new including the exhaust components. I had less than 1000 hours SMOH. Mine leaked from the riser that comes off the back of the manifold up to the turbo. I assume you have wet turbos on an '89 boat. The coolant may not be getting into the cylinder. You may be dumping it out the exhaust. It might get in the cylinder while running and it is being burned off. the danger is if it does leak down into the cylinder while at rest you could end up with hydro lock. Take off the turbo and look down the exhaust with a scope. See if you can find a point of origin or trail from a leak. The pin hole in mine wasn't visible but the trail was. Everyone thought mine was from the head gasket or a cracked head as no other signs of a leak were found. My entire exhaust was removed , reassembled in a shop and pressurized. No leaks found. The head was fine. Mine only leaked while engine was hot. No sign of a leak while running at cruise or at low temps. After the engine was stripped to the block and rebuilt, the leak was still there. That's when they went back to the exhaust again and found the trace of coolant. The mechanic was able to patch the leak as a temporary fix. Ordered a new riser and no more leak.

[Will]

This thread covers some options on checking exhaust manifold without removing it from the engine.
"Need help - DD6-71 coolant issues"
Will

[Jim saco]

Jack Thanx for your replies. I'm going to try and Jimmy some fittings up and pressure test the outboard side with the head in place. I hope it's in the exhaust. That would be the easiest option at this point. I dropped of the manifold and riser that connects the manifold to the turbo collector. If it's in the exhaust it will be in those 2 items. The turbo on this model I believe to be dry. I could be wrong. I wouldn't know the difference. My turbo has oil lines running to it and is before the shower head. Can someone tell me what the difference would be between wet and dry turbo's?
Thanx

[saltshaker]

Jack Thanx for your replies. I'm going to try and Jimmy some fittings up and pressure test the outboard side with the head in place. I hope it's in the exhaust. That would be the easiest option at this point. I dropped of the manifold and riser that connects the manifold to the turbo collector. If it's in the exhaust it will be in those 2 items. The turbo on this model I believe to be dry. I could be wrong. I wouldn't know the difference. My turbo has oil lines running to it and is before the shower head. Can someone tell me what the difference would be between wet and dry turbo's?
Thanx

Do you have exhaust blankets? A wet turbo is cooled by the FW side of the engine. The exhaust riser would also be water jacketed. The wet turbos have a single large turbo.