universal diesel model 5411 overheats!

[Mel Torres]

I just bought a 1980 Catalina 30, hull #1987. It has a universal diesel model #5411 11 hp. It's been running a little hot 165-180 degrees. The manuel calls for an operating temp of between 135-155 degrees.I've replaced the thermistat and water pump assemably. I've even gone as far as removeing the exhaust manifold to check for salt and carbon build-up (checked out ok). But the exhaust pipe leading from the manifold to the aqua lift muffler was totaly loaded with salt and carbon deposits! A quick trip to the plumbing shop took care of that problem. I reassembled everything and to my dismay it still is over heating! What gives? I've been told to flush the engine block with a solution of 50/50 muriatic acid and water. Any comments on the acid treatment? Is there any thing I'm missing? Any help would be very helpful. Thanks in advancemelOne more thing. there does'nt seem to be very much water coming from the engine exhuast port on the transom. I've been told that this is typical of the 5411 universal diesel. Any comments? Thanks AgainMel

 

[James]

Model 5411 Cooling

Mel,Here's a couple of thoughts;1. Water pump - you may need to replace yours. Inspect it and make sure it's not showing wear. Also, check your impeller. If your pump is a Sherwood, after overheating the impellers deform and won't deliver proper flow.2. Thermostat - the 5411 thermostat closes when it reaches operating temperature. This is opposite of a typical thermostat, which opens at operating temperature. Make sure your thermostat is for a 5411, not another universal model.3. Raw water intake - is your intake free flowing? If your thermostat is correct for the 5411, the most suspect place to look is the raw water pump. After overheating, the pump will continue to circulate water, but at a reduced rate. You will continue to overheat. Hope this was some help.James in Dana PointS/V Tesori

 

[Steve Franklin]

Acid

Check out Dick Dickens "Tech Talk" manual. Has some good info on engines. Be VERY careful if you use the acid flush on the heat exchanger. Some folks have said that it is easy to destroy the exchanger by leaving it soaking for too long. I have #1444 with a 5411, but have had no problems. Good luck!!

 

[Mel Torres]

universal 5411 over heat problem solved!

Thanks,Steve and James for your response. I knew I could count on CO and it's readers for help. According to the local chandlery there is only one thermastat that fits the 5411so I bought one and a new water pump assembly also. I even replaced the pipe assembaly leading from the exhaust manifold flange to the aqua lift muffler(the later done due to serious corrosion inside and out of the pipe which might of coused exhaust flow restriction). Like I said in my previous post I still had the over heat problem.So I did what I should of done from the get go, I disconnected every hose one at a time starting at the thru-hull to check for water flow. I finaly found the cause. It was a small valve in a 90 degree hose fitting at the lower right (starboard, for the salty dogs out there. Ha ha!)side of the engine that had corroded and just about totaly blocked water flow except for a fine mist. Hardly enough to cool a masquito on a hot summer night let alone fire breathing engine! Turns out that some folks put a valve in to adjust water flow for those chilly mornings when the engine has trouble comming to life. I think thats fine but you got to check it and all of your vessals systems periodicly. Also If you decide to intall one of thses niffty valves, make sure you do so down streem of the water pump so as not to restrict water flow to the impeller, other wise you'll damage it. also don't use the seacock valve that supplies the water pump for this purpose or the same damage will occure to the impeller.I hope that my bout with and resulting solution to my over heating problem will help some one in the future with the same problem. Better yet I hope no one has this problem ever.Thanks again catalinaowners.com, Steve and James.Happy Sailing, SincerelyMel Torres, Long Beach, CA.

 

[David]

Universal 5411 over heat problem

Mel I have a 79 model with 5411 and had the same problem. In changing the thermostat I noticed a washer in the bottom of the thermostat bowl where the water goes back through a mixing tee at the thru hull. Took it out and no water would come out the transom. I then installed a valve in the line from the thermostat to the mixing tee and left the washer in place. The washer kept enough water from going to the mixing tee to push water out the transom. Now I open the valve in winter to circulate warm water back to the engine to warm it up and close the valve in the summer which makes the engine run cooler. worked for me.