I was having a conversation with a friend who owns a Beneteau about an engine problem. She showed me a video that showed steam coming from the exhaust. This is a persistent problem that is happening on a warm sunny day. What could cause this? That is all the info I have. I do not even know what type of engine it is except that it is a diesel.
Steam comming out of exhaust
- Thread starter markwbird
- Start date
This can happen when the engine overheats some--as in a lack of cooling water noted above. I've had the same thing happen on the Bavaria several times. I have sail drive where the water intake to the diesel (Yanmar) is not protected (i.e., not screened). Consequently, debris such as kelp and plastic bags can get sucked into the water intake. Two ways I've found to deal with it. If not too big of a clog--back flushing the intake upstream of the filter will blow out the debris. You can do this with a hose at the dock if you can fit the connection hose barbs, etc. If a plastic bag is stuck in the hose you might have to remove the hose at the seacock to pull it out. Also, should check the filter bowl to make sure it is not plugged full of kelp or other debris.
Clearing the hose by back-flushing when away from the dock requires some apparatus that you can use on the boat. Since the engine compartment access door is in the aft head and the seacock on that side of the engine, I use the pump on the head to back-flush. I just connect via hose barb the head intake with the hose to the seacock. Thus, I can suck up seawater with the head pump and discharge it though the seacock which clears the clog. Plenty of pressure. You do have to stop the engine, however, to do that.
Obviously, after this is fixed, advise your friend not to motor through any floating patches of kelp debris--even small ones.
Clearing the hose by back-flushing when away from the dock requires some apparatus that you can use on the boat. Since the engine compartment access door is in the aft head and the seacock on that side of the engine, I use the pump on the head to back-flush. I just connect via hose barb the head intake with the hose to the seacock. Thus, I can suck up seawater with the head pump and discharge it though the seacock which clears the clog. Plenty of pressure. You do have to stop the engine, however, to do that.
Obviously, after this is fixed, advise your friend not to motor through any floating patches of kelp debris--even small ones.
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Strainer could be clogged, raw water pump and/or impellor damaged, Hx clogged with broken impellor blades, tiny brass elbow on exhaust elbow clogged, etc.
It has a lot to do with ambient temperature and humidity.
If engine exhaust comes out warmer than the air temp, a warm sunny day may not be that warm if the exhaust is 100+ degrees.
I'd first check the gauge against a thermal gun and if they agree, then no worries about the gauge (180ish degrees F?).
How is the flow of water out the exhaust? If it is strong, though pulsating, that is OK and it's probably the weather. If not, their impeller should be changed whether it seems bad or not. If there IS a temp problem and it shows up on the gauge (over 180 degrees F) and the gun, several above have pointed to possible causes and I need not repeat them.
If engine exhaust comes out warmer than the air temp, a warm sunny day may not be that warm if the exhaust is 100+ degrees.
I'd first check the gauge against a thermal gun and if they agree, then no worries about the gauge (180ish degrees F?).
How is the flow of water out the exhaust? If it is strong, though pulsating, that is OK and it's probably the weather. If not, their impeller should be changed whether it seems bad or not. If there IS a temp problem and it shows up on the gauge (over 180 degrees F) and the gun, several above have pointed to possible causes and I need not repeat them.
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Boring info from me...
1) Exhaust quenching normally makes theses gases 100% Humidity at Muffler liquid Temperatures.
2) Visible "steam" from the 100% Humidity exhaust gases is caused by Relative Humidity of outside air.
3) Over heated Muffler water will make higher water, gas content or higher Humidity [not relative humidity]
So what?
You can only use the Steaming exhaust analysis when you know the TEMPERATURES of the exhaust liquid.
To detect a Water cooling quench problem you must measure the exhaust water at least 3 different engine RPM's.
[Idle, Mid, Max rpm would be best]. A large difference in those measurements would confirm a quench problem.
Jim...
PS: When I see steam from my breath on a Cold low relative humidity day, it says nothing about the operations of my internal heat engine cooling. Except the I am alive.
Most likely the engine is running hot. It may not be hot enough to trigger the temperature sensor but hotter than normal. It may point to obstruction building up inside the raw water hoses. Like Capta suggests verify the water flow by the strength of the discharge. Also Don indicates that for different make engines it could be normal. Find out more information.