M-18 Overheating!

[Elrod]

Hi All, First Post and looking for help.
1984 Ericson 30+, Universal M-18 original engine. This Spring put new heat exchanger, new hoses, Alternator bracket factory recommended replacement ( circa1991), Removed exhaust manifold and elbow and had both boiled clean, new gaskets, etc.
Today, after many summer sails and moderate engine use, the engine overheated and generated a large volume of steam. By the time I noticed, the temp gauge was nailed high. Shut down engine. Sailed home.
At mooring with engine cooled off, re-filled with coolant and there is a drip from one of the bolt holes where the long threaded stud goes through the manifold. I believe that the hole is drilled through solid cast iron within the manifold and there should not be any water coming out the bolt hole. clearly the washer and nut are not intended to keep water in.
Is my exhaust manifold cracked or corroded internally allowing coolant into the hole? Was planning to leave tomorrow on a one week sailabout, guess it will be without engine.Thoughts (and prayers) appreciated. Did anyone notice it is Friday the 13th?
Thanks in advance, Elrod

 

[Dave G.]

My first thought is one of the new gaskets has failed or never fully sealed and a slow leak drained your coolant out over time. After refilling I would run the engine and look for the leak to pinpoint it. Is there a gasket in the manifold of the through bolt you said was leaking ? Just some input as I am not familiar with the M18 as mine is a 5416. What hull # is your boat ?

 

[Kenneth K]

My first thought was the same as Dave's--gaskets. But then, remembering back to my manifold removal, the only gasketed surfaces in that area are the "dry" exhausts ports. The "wet" exhaust flange gasket is off the rear of the manifold, not near the manifold studs.


(M-25)

The manifold itself (at least, on the M25) is "sealed" except for the inlet and outlet hose fittings, pressure cap, exhaust flange, and drain plug.

However, if you had a boil-over, it's likely that antifreeze got into some cracks and crevices of the external engine parts-- the manifold studs included. I'd try running the engine at the dock and carefully observing the manifold area. You may just need to dry off the engine from the previous boilover.

Then, determine the cause of the overheat.

 

[Elrod]

Dave and Kenneth,
Thank you both for your thoughtful responses. Took off the alternator and cooland is coming out of the forward lower stud hole where it comes out through the new alternator support bracket. I hope that you, Kenneth, are correct that it is just residual coolant from the boilover event finding its way out. Taking off the manifold and exhaust elbow was fun enough at home, not something I wanna try on my mooring. Timing was not great. The day before our 10 day costal cruise! Trying an engine free cruise with fully charged batteries and a new 50 watt solar panel to be installed en route. One does get spoiled with the engine available.
Will probably struggle through the season, pull the boat early and attack it then. Disappointing as I was so proud of my spring projects. I love my boat, I love my boat, I love……
Thanks, Elrod

 

[amazon43]

If your coolant level didn't drop, the problem is more likely associated with the amount of raw water moving through your heat exchanger, exhaust elbow, muffler, and exhaust hoses. Several things come to my mind: 1) total water flow from raw water pump -- if deficient, then blockages/restrictions between thru hull and pump could be a problem. A vacuum/pressure gauge T'ed into the system on each side of the pump will show you if the intake side has a restriction. I had a piece of bark enter my thru hull, pass through the seacock and hit a 90˚ el fitting upstream of the strainer. It lodged there and called an overheat. 90˚ fittings and T-fittings really should be avoided if possible. Looking at back pressure on the output side of the pump will let you know if there is a restriction. Hoses are made up of layers. The inner layer can debond and cause an inner blister restricting flow. Vinyl tubing is to be avoided for use below the waterline. It kinks so easily plus it gets brittle with age. Find a way to tap the pressure gauge into the exhaust at the elbow. The engine manufacturer has a maximum allowable exhaust back pressure. Many strange things can cause a high back pressure. Happy to help you brainstorm ideas if you find a high pressure. Exhaust hose inner blisters are common and can greatly reduce flow. They typically blister when you lose adequate cooling water and raw exhaust contacts the exhaust hose. The outside may appear fairly normal but the inside may be toast (toasted). 2) if raw water flow from the pump appears to be below normal but other things look okay, the pump itself could be the cause. If the impeller is slipping on the center metal bushing, it can look okay but not produce much flow. If the pump housing is worn front to back, water passes beside the vanes. If the pump cam is worn, there may not be enough lift to force out much water. Pulleys and belts could be an issue -- just straight forward deficiencies you can see or check easily. 2) If all of this checks out okay, there could be a problem with the engine coolant circulation pump. I have seen cavitation and or corrosion wear the vanes down to nubbers so they hardly circulate the coolant. Good grade, fresh coolant protects against corrosion and cavitation as well as freezing. It should be changed at least every two years. 3) the age old thermostat could be an issue. I have seen the strap over the pellet break loose, I have seen the wax ooze out of the pellet so the thermostat can't open. If in doubt, take it out, suspend it in a pan of water and slowly increase the water temp as you measure it with a candy thermometer or some such. Note the temp when it starts to open and when it is fully open. There will be published spec for both plus a dimension for how far it should open.

I know this can be tedious but that is what troubleshooting is. Except for a warped mind like mine. I love the puzzle and finally finding out the professor did it in the study with the pipe wrench.

One more little thing, ABYC P-1.7.1.4 standard says : An indicator shall be provided at all helm positions to indicate loss of exhaust system cooling water supply.

We know most builder totally ignore this standard. You can take a hose off the top of the engine raw water anti-siphon loop and route it up where you can see it flow. I saw one teed into a cockpit drain right by the wheel. You could hear and see the water flow. Ignore the puff of smoke that comes out of the cockpit drain when you start the engine.

I love boats.

 

[Elrod]

Amazon43,
Thanks much for your lengthly, detailed and helpful response! Gives me a good road map of a logical approach. Admit I felt a bit overwhelmed and hopeless. Your response has given me some hope that my 37 year old diesel may not be “toast”. New heat exchanger and Groco strainer this year. New exchanger has opening ports at each end. Old one had no opening at zinc end so I cut end off after removal and was amazed at the zinc bits accumulated there. 50% blocked I would guess. That is the end which should have been removable. Anyway, pump working properly and raw water side is not the problem. Will move down your helpful list.
Had to laugh at your “Clue” reference, been a long time, but you are right. Just need to get my head jn the right place and plow through the clues.
Thanks again, Elrod

 

[amazon43]

Elrod, best of luck to you! Enjoy your vacation. I am leaving Friday for a 2 week charter in the Puget Sound.
My email is alison@almsurvey.com is you need a quick response at any time

 

[Saullincer]

ok so I have been an auto mechanic for 40+ years and I have an Ericsson 30+ also. It sounds like you covered all the bases with your cooling system maintenance/repair. When refilling the system you must bleed all of the air out of the coolant side on the system. I had this problem on my boat and many cars that are difficult to get the air out. I've installed a bleeder valve in my "heater hoses" to the water heater to facilitate the process. sometimes you can remove the hose at the highest point as you fill coolant. I have had this problem more times than I like to admit, but you must bleed the air out if it has any way to get trapped in the closed system. Hope that helps.

 

[Saullincer]

Also if you have coolant weeping or leaking from a bolt or stud, sometimes they are drilled through to the cooling system and will require some pipe thread sealant or tape to seal them up.

 

[amazon43]

ok so I have been an auto mechanic for 40+ years and I have an Ericsson 30+ also. It sounds like you covered all the bases with your cooling system maintenance/repair. When refilling the system you must bleed all of the air out of the coolant side on the system. I had this problem on my boat and many cars that are difficult to get the air out. I've installed a bleeder valve in my "heater hoses" to the water heater to facilitate the process. sometimes you can remove the hose at the highest point as you fill coolant. I have had this problem more times than I like to admit, but you must bleed the air out if it has any way to get trapped in the closed system. Hope that helps.

So true! I forgot to mention that. One of the very basics. Steam from the exhaust had me going down the raw water path.

 

[G Kiba]

Did you recently replace your raw water impeller? I just had a brand new one fail on my M18. The impeller hub sheared and rotates without the vanes. It worked fine for a few weeks and then suddenly failed. Pull the cover off and have someone hit the starter to see if the impeller vanes spin.

 

[Elrod]

G. Kiba,
Thanks for your response. Last year had problems with the raw water pump and after replacing impeller and gasket and getting on again off again flow, finally gave up and rplaced it with new Oberdorfer pump. Works well now. Also all hoses replaced.
Saullincer
Thanks to you also. I admit I was probably a bit cavalier about getting any air out of the system after filling the coolant side, running engine to operating temp, snd all seemed good. Got cocky I guess and should have been more diligent in checking coolant level! I am pretty good at keeping an eye on water flow out of exhaust, but apparentlynot so good at watching the temp guage. An audible alarm for high temp would help.
Amazon63,
Thanks for your additional thoughts. I should have been more explicit: steam was not in fact coming from exhaust pipe. It was pouring out of engine compartment which is open to the port lazzarette on the Ericson 30+. (After the fact, I realize that it was a mistake to throw open the lazzarette cover, had it been a fire, woulda been a bad thing to do)

 

[Elrod]

Just a final thank you to all you knowledgeable people for sharing your wisdom with me…….very helpful. Day four of our cruise without engine. So far, so good. 50 watt solar panel, installed en route is keeping batteries more fully charged than normal morning engine run would have. Being conservative with consumption, but full charge at end of day 4! Work to do when back home, but enjoying for now. Thanks again, you folks are great!

 

[Elrod]

Soooo....... successful sail-about without engine for a week. Got back before the remnants fo Henri blew through. Interesting" sailing about without a working engine....did not venture offshore or into any tight anchorages. Did not want to get stuck "outside" without any wind.

Back to overheating M-18 Universal: Went to the boat (1984Ericson 30+) this morning. Dried off any residual moisture on the engine. tightened all hoses. Filled coolant. Bled all air I could through uppermost hose fitting. Topped up coolant. Engine started and ran at mooring. No visible sign of coolant leaking. Ran the engine at mooring to see if temp gauge and thermostat were functioning properly. Ran the engine for 25 minutes. Temp gauge barely moved: read 125 F at 25 minutes. (slightly above the low end of the scale, so believe reading is correct). Normally engine would have reached operating of 170-180 F temp after 10 - 15 minutes. Engine felt to the touch much hotter than 125 F.

Since the temp sending unit is in the thermostat housing the 125F reading could represent the actual temp of water there and not the actual internal temp of the engine if the internal fresh water pump is not working or the internals are clogged up some how. It seems to me that if the thermostat failed closed, the temp would be higher. And if the thermostat failed open, the engine would actually remain cool, not just register as cool on the temp gauge.

Seems to me, the right course is to just replace the pump and the thermostat and start fresh (37 year old components as far as I know. Questions: Is there any easy way to tell if the internal pump is functioning properly without special equipment or coolant splashing about? Would a non-contacting thermometer (point and click) be helpful in diagnosing problem? Can coolant get gooey and not circulate? Any and all thoughts would be helpful.

Thanks in advance, Elrod

 

[Alan Gomes]

I think you should get an inexpensive infrared thermometer. Using it, you could see what the temperature is at the thermostat housing and altimeter on the engine. I certainly would not trust the temperature gauge.

 

[Elrod]

Alan,
Infrared thermometer on order along with fresh water pump and thermostat. BTW for those that may not know: Universal M-18 is based on a Kubota Z-600 block and Kubota after-market pump set me back $34 at Kumarbrosusa.com vs. the $385 from the usual "marine discount" sources. Add another $18 and you get the thermostat too. Add another $25 and you get the Kubota Z-600 workshop manual so cross-referencing Universal to Kubota parts will be easier next time! Methinks the infrared thermometer is going to be very useful in diagnosing the cause, or at least the location of my overheating.
Thanks, Elrod

 

[Elrod]

Almost there?? Installed new fresh water pump, original actually looked OK. Installed new thermostat. Old thermostat was clogged with brown goo which methinks was root cause of overheating. After chasing down minor leaks by retightening bolts no leaks and engine running at 170 or so by engine gauge. Infrared gave various readings depending where on the engine I pointed it. Highest was 195 at top of block. Infrared thermometer is a fun tool for 20 bucks.

Thinking my work done, I poured remainder of 50/50 coolant mix into overflow tank and very disappointed to find. It leaking out under filler cap. Gave up for the day.

Searched this site for clues and hope that the cap is just not sealing properly and/or rubber gaskets not sitting right. my new expansion tank sits above the fill level and wondering if it should be lower? There is no leakage from the cap under now normal running conditions.

Feels like whack-a-mole!
Elrod