Steam in the exhaust: Ford Lehman SP135

[GeneO]

About 6 months ago I serviced the heat exchanger on my Ford Lehman SP 135. Took the whole unit apart, had it cleaned by a radiator shop, replaced the chewed-up impeller. Ran the engine for about 50 hours, no problem. Now, about 100 hours later, I'm seeing steam coming out of the exhaust. I wonder if this has anything to do with the heat exchanger.
Any thoughts or suggestions will be appreciated.

 

[markpierce]

Sounds worrisome. This would be something I'd bring to my engine mechanic. But then, I would have had the mechanic work on the heat exchanger originally.

 

[Edelweiss]

You know I see that question asked a lot. Here in the PNW when the temperatures outside are cool, my engine exhaust will appear to steam a little too. . . it will come and go. Probably more to do with the air temperature and dew point than anything else.

But don't dismiss it totally. It could be an issue with the engine or exhaust system. The first thing I would look at is the water level and coolant in the freshwater side of your cooling system to eliminate a possible headgasket problem or internal heat exchanger leak. If you're not using water or blowing water out the overflow, then it's probably not that. Then check your exhaust manifold and elbow temp while running to make sure they are not running hot. And check your exhaust discharge to make sure you have a normal water flow. Was the heat exchanger pressure tested?

Also with the engine running, pinch all the rubber hoses from the raw water pump to the exhaust elbow injection. If any are rock hard or bulging there could be a restriction in the piping.

If the steam isn't excessive and everything turns out to be normal, it may end up being nothing at all.

 

[Daddyo]

Often the cleaning will open/weaken welds in the exchanger. Probably a good idea to go ahead and buy the replacement and have it on board ready to go after a cleaning as it probably is just a matter of time. Happened to me before. Don't know if that is your problem just intended as a FYI.

 

[markpierce]

I've only seen water and and heard engine-exhaust sounds coming out of the Coot's exhaust exit. If saw smoke or steam ... time to see an expert.

 

[Peter B]

About 6 months ago I serviced the heat exchanger on my Ford Lehman SP 135. Took the whole unit apart, had it cleaned by a radiator shop, replaced the chewed-up impeller. Ran the engine for about 50 hours, no problem. Now, about 100 hours later, I'm seeing steam coming out of the exhaust. I wonder if this has anything to do with the heat exchanger.
Any thoughts or suggestions will be appreciated.

Don't panic Gene, your engine, (same as mine), is water cooled via raw water coming in, passing through the two oil coolers then the engine heat exchanger, then it is injected into the exhaust knuckle, passes out through a water muffler to the open. Mine often appears to contain a bit of 'steam' also, especially if travelling fairly briskly, but to me that's just normal. You have warm water entering hot exhaust gases, (which helps cool them, so not too hot for a hose type exhaust, otherwise it would have to be all metal), so a bit of steam is not too surprising. If you had a leak in the reconditioned heat exchanger, you would not see it coming out the exhaust. What your oil temp/pressure and coolant temp is telling you is what matters here, and if they are where they usually are, I think you are good to go, but no doubt others more knowlwedgable will chime in soon. Check your coolant for appearances which might suggest contamination and/or loss/or gain even, however…just to be on the safe side. If the coolant stays clean green, and similar level to usual, again, that is reassuring.

 

[markpierce]

If you didn't have steam before but did after the repair, I'd be worried.

 

[AusCan]

I agree with Peter. It has nothing to do with the heat exchanger. Thats the good news.
The bad news is it could be a head gasket or liner leak, but hopefully not. Keep a close eye on your coolant level. Also look for any evidence of coolant/water in your oil.

Hopefully it is just the cooler ambient temperature making the exhaust look steamier.

 

[Peter B]

If you didn't have steam before but did after the repair, I'd be worried.

Can you enlighten us on why you say that mark? With a wet exhaust, the only things passing out of it are exhaust gases, and water. Why would a bit of steam, or condensed water anyway, be of concern? What else could it mean..? It's not likely coolant from a blown head gasket would add enough to be noticed over the volume or raw water going through, and his temp gauge would soon make that apparent. I think you are being a bit alarmist, but I'm listening...

 

[markpierce]

I'd be concerned with an apparent negative change in an engine's performance/sound/exhausts after it had been "messed" with. We're talking about a diesel rather than a steam engine, after all. I'm not an engine mechanic and know my limitations.

 

[RickB]

Any thoughts or suggestions will be appreciated.

It's the middle of November now ... maybe air temperatures are a bit cooler?

 

[Captain K]

Had steam coming from my port FL 120 once big time! It was on a chilly December morning en route from Apalachicola, FL to Clearwater, FL. Water temp appeared normal!! No steam from stb engine. Turned out to be the impeller. It had shed about half its blades. I'd just replaced the impeller less than 25 hours before using one I found in the spares bin on the boat. I now realize that impeller may have been years old and brittle from age, as it was aboard with lots of other spares when I bought the boat. Installed recently purchased new impeller. Steam vanished. She's been running A-OK for 200+ hours since. Good luck.

 

[psneeld]

Agree that it's nothing to do with the heat exchanger....unless you think you INCREASED blockage someplace or the water out the exhaust is decreased.

Could be environmental like Rick suggested...often takes a combination of environmentals to make the steam seem much more prominent.

It could be coolant/head gasket...are you noticing a decrease in coolant...even slight?

 

[eseyoung]

Does the steam go away (or decrease) once warm?

either way i'd guess it is a matter of dumping raw sea water into a stream of hot exhaust.

If it were my boat i'd try to convince the admiral to allow me to immediately relocate it to a place with warmer sea temps. because, hey the boat needs it right?

I hear the Keys are nice this time of year.

 

[GeneO]

Great comments, all. Thanks for taking the time to "chime in."
I intend to check the impeller today, since that seems to be the easiest fix. As for the other indicators: temp is normal, around 160, according to the gauge; regarding the environmental aspect, I neglected to mention that the engine in question is the port side, and the starboard side (which I didn't "mess with") has no steam; the head gasket is the most worrisome of all, however, there is no water in the oil, judging from the clear appearance, and the coolant level has remained the same since performing the work on the exchanger. BTW, the reason I serviced the port side HE to begin with: the engine overheated, alarm sounded at 185 degrees, and I shut it down. There was hard growth build-up in the raw water intake, inside the screen and the through-hull fitting, allowing only a trickle of water through. The impeller had disintegrated, presumably from friction, having no water flow. I took the HE apart looking for remains of the impeller- all clear. Since I had it apart, I figured it couldn't hurt to have it flushed. A local radiator shop soaked it in a chemical bath for a few days, and it looked clean when I re-assembled it.

Another thing that I would enjoy hearing some opinions about: the starboard engine emits water through the exhaust in periodic bursts, about 5 second intervals, while the port engine has a constant flow which, by the way, appears to be adequate.
I have to admit that I had never observed the exhausts closely, prior to the incident with the port engine. I don't know whether they were both emitting water in periodic bursts before.
Thanks again to all.

 

[RickB]

I neglected to mention that the engine in question is the port side, and the starboard side (which I didn't "mess with") has no steam;

Ahhh, the rest of the story ...

Another thing that I would enjoy hearing some opinions about: the starboard engine emits water through the exhaust in periodic bursts, about 5 second intervals, while the port engine has a constant flow which, by the way, appears to be adequate.

Since it appears you have water lift mufflers and the starboard one seems to be getting enough water to fill it before backpressure rises enough to blow the slug of water out ... which cools the exhaust quite nicely as well but the port side only gets enough to cover the dip tube, I would venture a guess that the bits of rubber you didn't find in the heat exchanger might have found a home in the spray ring.

Next time you run the boat, feel the tubing just below the spray ring or injection elbow or whatever you have and see if the port is just a bit warmer than the starboard. If you don't want to do that, pull the exhaust hose at that point and see if the spray holes are partially blocked.

See if the starboard has hot spots on the upper side of the rubber tubing at the spray ring.

 

[Captain K]

Have you checked the oil cooler for bits of impeller? That's also quick and easy to do. Since it's upstream from the engine HE, and immediately downstream from the raw water pump, seems logical it would catch any debris before the big guy would.

 

[AusCan]

the starboard engine emits water through the exhaust in periodic bursts, about 5 second intervals, while the port engine has a constant flow which, by the way, appears to be adequate.
Thanks again to all.

You could be on to something there. Are both water lift mufflers at the same height? Was the port muffler or exhaust hose disconnected or moved slightly when you pulled the Hex?

 

[C lectric]

Another thing about broken impeller vanes is they can apparently travel upstream from the pump. We all look at downstream but some of those cheeky little beggars hide upstream and then when YOU think all is well and you restart the engine they come out of hiding to plug the coolers and heat exchangers again, Sometime shredding the new impeller.

 

[GeneO]

I didn't have time to replace the impeller today, but made some further investigations, based on all the great input I received.

• Started both engines: no steam from either; it was a warm sunny day with low humidity- score one for proponents of the "environmental" theory.
• Both engines achieved normal operating temp: approx. 160 deg. Easily discernible light blue smoke from port engine, very thin vapor of light blue smoke from starboard.
• Revved both engines to 2000 rpm for several minutes: starboard engine temp rose to 175; port engine remained at 160. Smoke output decreased to barely visible vapor from both engines.
• Physically checked temp of both risers: starboard riser was too hot to keep my hand on for more than a few seconds, while the port riser remained only warm. Not sure if it matters, but the starboard riser is cast iron, while the port is a welded assembly, appears to be stainless. See pictures.
• With engines running at normal operating temp., squeezed the hose exiting the aft end of the HE; the port hose had no tension whatever, I collapsed it completely with little effort; the starboard hose had considerable internal pressure- I couldn't collapse it more than 1/4 inch (see picture); same for the hoses exiting the trans oil coolers (see picture of port side.)
• Checked water output at exhaust: starboard discharged at approx. 5 second intervals, while port side streamed constantly, approx. 2 gpm.
• Rick B: I would like to try the investigation that you suggested, "feel the tubing just below the spray ring or injection elbow", but I don't know what the spray ring or injection elbow is. I have attached pictures of my exhaust system, hoping that you would identify the components that I need to check and, perhaps, elaborate on your theory.
• Captain K: I did check the trans oil cooler when I had the HE disassembled- whistle clean.
• Finally, while investigating the HE's, I noticed that there is a steady drip coming from my starboard prop packing gland. I guess that will be the sequel to this thread.
• THANKS ALL FOR CONTRIBUTING TO MY ONGOING EDUCATION.

 

[Captain K]

I'll be very interested to hear what you find when you check that port engine impeller. My bet is that it is damaged and has a few blades missing. Your exhaust situation strongly suggests you've either got a blockage or that raw water pump just isn't hacking it. In case you don't have one already, I'd also suggest you invest in one of those remote temperature guns. You shoot it at whatever you want to measure and it shows temperature with high degree accuracy. I just picked one up at Lowe's for about $30 and wonder how I got along without it before! Think it would be very useful in tracking down your problem. Good luck.

 

[skipper2]

Steam in the exaust Lehmans

Ahoy GeneO, I think I have an idea why there is difference in th exhausts. The two elbows are quite different & the welded one will insert the water int5o the exhaust in a very different manner. The cast elbow has the water injection on the top, and there is a welded plate under the water inlet which spreads the water and mixes the water with the gasses. So the results downstream are necessarily different. If it were me, I would call Bob Smith & see if there are cast elbows available & get their advice. Personally I don't like the welded elbow. Gayle

 

[Larry M]

Ahoy GeneO, I think I have an idea why there is difference in th exhausts. The two elbows are quite different & the welded one will insert the water int5o the exhaust in a very different manner. The cast elbow has the water injection on the top, and there is a welded plate under the water inlet which spreads the water and mixes the water with the gasses. So the results downstream are necessarily different. If it were me, I would call Bob Smith & see if there are cast elbows available & get their advice. Personally I don't like the welded elbow. Gayle

I agree that the difference could be the two different exhaust elbows but don't rule out the SS one. Ours which is SS, came from American Diesel whch they sell. We also have a SS exhaust elbow on our Northern Lights generator. Both get inspected and have been on the engines for 6 plus years.

 

[Bensjoy]

Perhaps you could also check the intake thru-hull, seacock and strainer for possible blockage which would inhibit water flow to the raw water pump.

 

[Forkliftt]

I agree that the difference could be the two different exhaust elbows but don't rule out the SS one. Ours which is SS, came from American Diesel whch they sell. We also have a SS exhaust elbow on our Northern Lights generator. Both get inspected and have been on the engines for 6 plus years.

Larry, I love the red covers on the ends of your hose clamps. Compliments the Lehman red perfectly......... (I have them too )

 

[Larry M]

Larry, I love the red covers on the ends of your hose clamps. Compliments the Lehman red perfectly......... (I have them too )

Thanks. And as you know they also cut down on the amount of blood that gets shed that doesn't compliment the FL.

 

[GeneO]

Great comments, all.
I will check the impeller today.
Any ideas why the hoses on the port side have no pressure when the engine is running at normal temp?

 

[sunchaser]

Is the RW pump(S) in good working order? More to it than the impeller.

 

[Edelweiss]

Great comments, all.
I will check the impeller today.
Any ideas why the hoses on the port side have no pressure when the engine is running at normal temp?

I was wondering the same thing when I saw your pics?? You shouldn't be able to squeeze the hoses flat with the engine running that easy. As soon as you pinch close the hose, water pressure should build up on the pump side. I'm guessing there is either not very much pressure out of the raw water pump or the spray ring in the exhaust elbow is rusted out or nonexistent.

Is this the stainless side of the cast exhaust elbow?

I would start with the raw water pump. Even if the impeller looks good, the pump maybe worn or water inlet partially blocked!! That is the most suspicious to me!!

 

[captrigney]

I see you have the exhaust temp. alarm. I have them, too, as well as the Aqualarm flow alarms.