Smelling coolant

[jclays]

Riding my friends boat. Twin Cumins turbo diesels. Idle speed to 1500rpm no issues.Starboard engine Above 1500 approaching 2000rpm smelling coolant.
elbow? Turbo?
Temperature stays steady.

 

[RT Firefly]

Greetings,
Mr. j. Start with the free, easy stuff: Hose and hose clamp integrity, pressure cap on expansion tank (if fitted), hose to HWT (if fitted), transmission/oil coolers, water pump etc. Perhaps put blue shop rags in and under suspect areas.

 

[DavidM]

On the Cummins, coolant is used in the main heat exchanger where it is exchanged against raw water; the block, head and exhaust manifold; the turbine housing and maybe the fuel cooler.

The only one that might start leaking under a load of 1,500+ rpm is the turbo. The coolant might be leaking into the air side of the turbo. The air suction pressure drops under higher rpm’s and it may be sucking antifreeze into it. It would then have to be burned in the engine and you finally smell it in the exhaust.

Well, that’s my wild ass theory, FWIW.

David

 

[Mainship Pilot]

On the Cummins, coolant is used in the main heat exchanger where it is exchanged against raw water; the block, head and exhaust manifold; the turbine housing and maybe the fuel cooler.

The only one that might start leaking under a load of 1,500+ rpm is the turbo. The coolant might be leaking into the air side of the turbo. The air suction pressure drops under higher rpm’s and it may be sucking antifreeze into it. It would then have to be burned in the engine and you finally smell it in the exhaust.

Well, that’s my wild ass theory, FWIW.

David

Makes perfect sense to me!

 

[fgarriso]

Before starting out fill the expansion tanks with coolant. Run both engines at 1500-2000 RPM for 30 minutes. Shut the engines down and check the coolant levels after the engines have cooled off. If one engine is lower than the other, then you know which engine is losing coolant. You can get dye packs to put in the coolant and then see if you have an external leek.

 

[rgano]

Pinholes in coolant surrounded exhaust manifolds have been know to be troublesome in some engines.

 

[PhilPB]

I had a very similar problem where I would have the odor of hot coolant but wasn't losing enough of it to see a visible leak. Had a pressure check done and found a pinhole leak in one of the coolant recirculation lines going to the hot water heater.

 

[High Wire]

Don’t overlook an extra jug of coolant leaking out somewhere.

 

[C lectric]

Have you gone around to EVERY hose connection clamp and tried snugging them up?
Hoses as they age shrink meaning the clamps may not be holding as well as they used to. Maybe not much but under operation it can be enough to allow small amounts of leakage.
You may not see any weepage as the amount is usually quite small and engine heat will often evaporate what does escape.