Inboard performance

[Randall Schmidt]

I have tried that very procedure with no luck. That was before I replaced the HX that did not look bad really. I had a marina mechanic with me this last time as we bled the system by briefing opening the thermostat petcock and frequently checking to ensure the coolant level was maintained.

 

[Richard19068]

I have tried that very procedure with no luck. That was before I replaced the HX that did not look bad really. I had a marina mechanic with me this last time as we bled the system by briefing opening the thermostat petcock and frequently checking to ensure the coolant level was maintained.

I don't know what else to say other than I've had some very frustrating times burping the system, sometimes taking half a dozen tries or more to get it purged.

Good luck.

 

[Randall Schmidt]

I'll try the idea from that thread with the ball valve and hose on top of the tstat housing. I wonder if he leaves the hose in place and coils it up or just removes it and keeps it on-hand after purging the air.

 

[Panta Rei]

Wow, just read over this thread. I feel for you. I recall somewhere back in the thread that you have a water heater. If that is correct, I hope you have taken it out of the system. It only adds to the complexity of the problem. It should be plumbed in such a way that only a portion of the coolant is running trough it.
Maybe you covered this earlier, Sorry if I missed it in the thread.

 

[Randall Schmidt]

I've replaced the hoses to the water heater, the water heater itself I'm told is not functioning since I purchased the boat last April. I've not tried to use it nor have I turned it on on the switch panel. I intend to replace it but was trying to put that off for another time. What is your recommendation on the heater?

 

[Randall Schmidt]

I replaced the lower thermostat housing that had a crack in it. I open the engine block drain valve and nothing came out. I then removed the plug and poke a tiny screw driver in the hole to get things flowing, Next I poured water into the thermostat housing (while the thermostat was out) and caught most of the drainage in a container, it had tiny metal shavings and other depris in it. I flushed a few gallons thru it and it got cleaner. I ran her on water for 5 minutes w/o a thermostat in place then opened the drain valve and not much comes thru. I may remove the plug again, the day is over, I'll be back at it again tomorrow.

 

[Randall Schmidt]

I am going to install a raw water strainer, surprising to me she does not have one and I could use it to make winterizing easier. I recently replaced the raw water intake hose. It is a 5/8 ID hose. The water strainer/filter comes in 1/2 or 3/4 I'll find an adaptor but West Marine does not have one, WM guy told me to ditch the 5/8 and change over to 1/2 or 3/4 hoses all around as 5/8 is rare and hardly used anymore. Too bad I just spent a lot of effort replacing with new 5/8 hoses. that chore will be put off but I thought I'd share his advice.

 

[Davidasailor26]

I've replaced the hoses to the water heater, the water heater itself I'm told is not functioning since I purchased the boat last April. I've not tried to use it nor have I turned it on on the switch panel. I intend to replace it but was trying to put that off for another time. What is your recommendation on the heater?

I believe it should be possible to remove the coolant hoses from the water heater and connect that part of the circuit in a loop without the heater, which may help troubleshoot.

 

[Panta Rei]

Yes, by all means get the water heater out of the equation. There is a drawing on the second page of this thread. Follow that.
Don't reinstall the thermostat. it too just adds complexity to the trouble shooting. Don't put anti freeze in the coolant loop until you figure this out. Run the engine open the engine block drain valve and keep adding water. wait for it to over heat.

 

[Panta Rei]

I quickly scanned the thread but found no mention of flushing the coolant system. There are products at auto parts stores for this.
So to summarize:
Start with the engine cooled down a bit. With the thermostat out, water heater out of the circuit. Coolant cap off. Run the engine. Can you look into the coolant reservoir? (the box like thing with the coolant cap) I would think that you should see the water moving. put your finger in there. It should slowly get warm as the engine runs. Be careful, the hoses, engine, and reservoir should all be heating up at the same time. Check to see water coming out of the exhaust. Put the cap on and wait for it to overheat. When it does, is everything HOT? Are the hoses to the heat exchanger Hot as well? Is the heat exchanger very hot?


If the water in the reservoir heats up and is flowing, The coolant hoses to the heat exchanger warm up as the engine warms, the only thing I could think of is to flush out the coolant system. Follow the directions on the package.

 

[Randall Schmidt]

Here is the latest in my saga. Recall. I already replaced the HX, the fresh water pump and the raw water impeller and all the hoses - even those that go to my non-functioning water heater. I removed the engine coolant drain plug as the valve when opened was clogged. I took off the thermostat top and poured in water, I watch it drain out the plug with lots of crud. I replaced the tstat housing w/o the thermostat and ran her with toilet bowl cleaner for 15 mins or so. Let it sit for 30 mins. Drained it, then refilled with baking soda/water mix, ran it and drained it. Took off tstat housing and poured gallons of water thru the system till the drain water came out clean. Then I filled her with antifreeze/water mix. following the advice of a link on this site, I replaced the petcock on top of the thermostat with a valve I can open into a clear hose clamped on and pointing up vertically. I filled the hose with coolant. With the thermostat in place, I ran the motor till the tstat opened at 180 then opened the valve and watched air bubbles come out and coolant get sucked in to replace the air. Motor got up to close to 200 each time (under load as it was in geat but tied down at my slip) so I killed the motor and watched the bubbles escape before restarting, refilling the hose and testing again. I did this about 5 - 7 times over about a 4+ hour period. She ran slightly cooler each time but each time I got into a too hot zone 190 - 200 and saw bubbles escaping. Finally had to stop the day's work as a storm came rolling in, it got dark, rainy and very cold. I may be just one more iteration of burping to clear the system of air. I HOPE SO! I'm hoping this will solve my problem. If it does not I'll rig a loop to take the heater out of the equation as suggested. My diesel mechanic buddy says I should try leaving the toilet bowl cleaner in the system for 24 - 36 hours to eat away more crud but at the moment he thinks finishing the air purging process will solve the hot motor issue.

 

[Randall Schmidt]

As I think about it, I may have done the air purging cycle activity about 10 times in a row. It takes about 15 0-20 minutes for each round it seems. Watching the bubbles dissipate is time consuming

 

[Stu Jackson]

I may be just one more iteration of burping to clear the system of air. I HOPE SO!

Why not stop hoping and use some engineering, you know, like the guys who built your engine.

Your engine may be similar:

Engine Overheating 101 - How to Burp Your Engine (Reply #6) http://c34.org/bbs/index.php/topic,4518.msg26462.html#msg26462

 

[Randall Schmidt]

thanks Stu. I read that reference and there are many stories there. I believe you meant the description of pulling the 3/8" hose off the thermostat and pouring coolant into those till it comes out the thermostat nipple. Sounds like a great idea. I'll try that next time I'm a the boat after one more (probably) final round of burb

ing via the technique I also found on this forum. I've attached a picture of the approach I used yesterday.

 

[Stu Jackson]

1. and there are many stories there.

2. I believe you meant the description of pulling the 3/8" hose off the thermostat and pouring coolant into those till it comes out the thermostat nipple.

1. Yes, but my link sent you to a specific post on that entire topic, the one with the picture.

2. Yup.

Sometimes it's hard to get air out of a SYSTEM by just filling from the top. Think about it. Maine Sail's idea of an air vent is that it lets the air OUT at the top. You're filling from the top. Where is the air going to go? How will it get out? It can't. By using the linked method, you are pouring water into one side while forcing the air out the other.

Good luck.

 

[Randall Schmidt]

One other thought a couple friends mentioned to me tonight, if I keep getting air in it as I burp the system maybe there is a way that new air is entering the system as I purge old air from it. Something like a cracked block perhaps. I'll do a compression test to see if that could be the issue. Any thoughts on that? I'll also try Stu's method of pouring coolant into the hose at the bottom on the thermostat. Does anyone have a tip on where to get a new motor in case I end up going that route?

 

[Davidasailor26]

I would think any cracks or splits would be more likely to let the pressurized coolant out than air in.

 

[Panta Rei]

I'll leave the burping process to you guys. Air woks itself to the reservoir in my engine. I hope burbing solves the problem for you.

BUT, should it not, I think you need to focus more on trouble shooting and less on repairing/replacing. Have you just started the engine up cold and felt each component as it warmed up? Examples, The hose running to the water heater does it get hot? How about the hose returning from the water heater? Same for the hose from the engine to the heat exchanger, Is that getting hot? Is the hose returning from the heat exchanger slightly cooler than the hose running to it? Is the hose from the heat exchanger to exhaust elbow warm? Look in the reservoir and check if the coolant is flowing. The people on this forum are very solid mechanically but they are not on your boat.
I keep thinking about that water heater. There should be no need to turn it on at the electrical panel. The heater heats water in two ways. One with a electrical element, the other from the engine coolant. It should be making hot water unless there is a blockage or maybe a valve installed in line. I have a set-up that allows me to control how much of the coolant flow is sent to the heater. The balance goes to the heat exchanger. How is your heater hooked up? A few photos or a sketch may be helpful. A previous owner may have hooked it up wrong.

 

[Randall Schmidt]

thanks for these additional ideas. I will try them out when I make the trip back to the boat next. As for the water heater, the seller said it was non functional. I plan to replace it at some point. I will feel the heat flow as you suggest and rig a way to bypass the heater at least as a troubleshooting step. It seems logical though to still get the air out which I'll continue to pursue via the tstat valve/hose fill approach and the pour fluid into the bottom hose that enters the tstat housing.

 

[Panta Rei]

Keep in mind the engine, heat exchanger, plumbing system was designed to not trap air. It would have a service notice and precise instructions on how to burp it had the engine been released with such a design flaw. Adding the loop to the water heater is what causes air to be trapped, certainly if it is done wrong. You will not need to rig anything to restore the system to it's original design. Simply follow the drawings posted earlier on this thread. You should have enough hose. Here is in excerpt from Betamarine's website. "If you are going to fit a hot water heater and let the coolant from the closed circuit of the engine heat the water for you, It is essential to get the plumbing correct so that you don’t have an overheat problem with your engine. Keep the supply and return lines between the engine and hot water heater as short as possible and avoid any big loops or dips in the hose." since your water heater is not working, it's likely not plumbed correctly. It's as simple as the heat exchanger. Not much to go wrong once it is installed correctly.

good luck!!!