Overheating Universal 5411

[JohnBassett]

Anyone with experience in raw water cooling systems on the Universal 5411 Diesel?
Mine overheated badly last trip out.
Strainer is not plugged as I am getting fresh, cool water to the water pump.
My assessment of the options for troubleshooting are water pump impeller, thermostat, or blockage in the cooling water lines or block. Any other ideas? Is there any possibility for air inleakage at the strainer not allowing enough water to be drawn from the strainer? Any ideas will be greatly appreciated as our sailing season in Northern Ontario is not long.
Thanks.

[ospe]

I had the waterpump, thermostst, and temp sensor all go bad within 4 months on my 5411. I would suggest replacing them all. The cost of a new water pump was about the same as having the old one rebuilt so I put on a new one. they are all very easy to replace and with the 5411 being raw water cooled they are probably due to be changed.

[JohnBassett]

Thanks ospe
Replaced impeller and have thermostat on order,but problem turned out to be blockage in the block itself. Flushed with garden hose(many times) and now have good flow coming out of exhaust. Thanks for the tips.

[HyperJoe]

Could you tell me how much water is supposed to come out of the exhaust? Also, does it take a few minutes for the water exhaust to appear? It takes my 5411 10 minutes before it begins showing water exhaust, and then its only a cup or so every 45 secs. The temp shows 150-160 at crusing speeds. I ran it over 5 hours full and nothing above 160. Does that sound right? Im new with the 5411 and any help is appreciatd. Thanks

[BarryHoy]

Folks,

Have 5411 in Pearson 32 (1979). 1241 hours on the engine. (Actual running time is somewhat less since the ET meter runs when the key switch is on.) Operate in the Chesapeake Bay. My engine operates well at about 140 to 145 degrees. People who owned the boat before me have about twelve years experience with the boat. He maintained the temp in that range and was very careful with maintenance.

Tnx,

Barry

[roywmoss]

My 5411 operating temperature seems very much a function of the seawater temperature. In warm water it seemed to run about 200 degrees or more (run at max rpm for hours on end) and it was exhausting the paltry amount described in one of previous posts. I was unaware there was a thermostat and I installed a manual ball valve in the recirculation hose to adjust/stop recirc. in warm weather. By eliminating the recirc., it exhausts twice the water, which I find reassuring. It may operate below optimum temperature (a supposed diesel no-no), especially in cold seawater, but perhaps this will reduce buildup in the cooling channels and explains its (27 years) longevity?

[jacksw]

Check the exhaust elbow...had that happen to me. I like the ball valve suggestion to stop recirculating water. We are in Mexico and that is a great suggestion to be able to adjust/stop recirculation. This engine is supposed to be run at 135-150 degrees. We do, but like the option. Another mod I did was plumb the sink to the engine with ball valves on each leg. Shut off sink thruhull, fill sink with fresh water, open valves to engine after closing engine saltwater intake. Run fresh water thru engine to flush it. I add radiator lube/anticorrision thru it also by adding it to sink water. Stored this way for 6 months of each year. Great little engine.

[mrkeith]

hi, any thoughts on this one? i have a kubota 22hp, which had been operating flawlessly for the last 6mths. suddenly its started the following traits- it will run great for about an hour at 2500rpm, engine pressure ok, temp ok, water out the exhaust ok, then for some reason, oil pressure drops, temp goes up, and the engine overheating alarm goes off. i shut the engine off for about 15minutes, then everything is fine again until the next occurence. any suggestions?
btw how do i put that radiator anti corrosion stuff in my engine? do i just add it directly to the radiator w/ some water?

sorry for asking what may be a dumb question. thank you

[BKEELER]

I have a 5411 in my 1980 Catalina 30. The exhaust water output is similar to other posts in this thread, but I have seen 5411's put out much more water. I maintain my engine temp after warmup at 140. It concerns me that I have my engine "innards" exposed to salt water all of the time. I am considering removing the thermostat so I can flush the cooling jackets with water starting with lower pressure garden hose and move up to using a pressure washer to throughly flush the cooling jackets and possibly even use a vinegar rinse--leaving the vinegar in the engine for 24 to 48 hours at a time before rinsing it out.
I would also like to do a mod where I have a 3-way ball valve (mounted in cabinet under sink) with 2 inputs (salt water and fresh water from water tank) output to engine. That way it would be easy to fill engine with fresh water each time you turn engine off

I would appreciate comments from people on both the flushing idea AND the modification.
Thanks

[JimsCAL]

For anyone running your 5411 in salt water, there is a good chance that the cooling passages are clogged with scale. Time for an acid flush. I have had to do that on my 25 year old 5411 several times. Oxalic acid from the hardware store circulated with a portable pump will safely and quickly dissolve the scale buildup. Vinegar isn't strong enough. Don't forget to remove the thermostat to permit free circulation and avoid possible damage to the thermostat.