Coolant shut off location

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Nva

Hi All,
We seem to have the dreaded water heater coolant leak on our 2011 R27 with the Yanmar 4by2 engine. Have read other posts on this topic the is a coolant shut off valve on the port side of the engine near the oil dipstick.
We found what looks like a plastic knob with a cross cut on it that looks somewhat like a large plastic phillips head screw.
Could this be the coolant shutoff valve? Not clear in the engine manual. I have a photo and can attempt to post it in a follow up post.
Thanks, Nita
 
I also have the 2011. I was not aware of a shut off valve. I believe what you are refering to is a "screw vent" according to the parts manual. You could remove to hoses at the connecting points on the port side and then attach a small piece of the same size hose to the connections with a plugged end. Before you do that, did you check and tighten the connections at the rear of the heater? This is accessed through the access door under the head sink floor. You have to do this by feel. Also check the cabin heater under the helm step. Those clamps tend to losen as well.
 
I have that entire area of my 2010 R-25 in a zillion pieces looking for a coolant leak.

There is no shut off valve! If you were to install such a valve, you must put on on both the feed and return lines directly above the alternator on the port side of the engine.

Such a valve would shut off water to both your domestic hot water heater and your "bus" heater located under the helm.

There is a much easier and less expensive solution.

Remove the heater, it slides out a small distance easily,.

Remove the two hoses and join them together with an "elbow" suitable for 5/8" ID tubing. You can reuse the original clamps.

Home Depot sells the necessary elbow as a 3/4" PEX fitting. PEX is measured in outside diameter of the hose - so the 3/4" fitting is really a 5/8" tubing fitting.

Job takes just a minute and is easy to reverse.
 
From the information given by Knotflying and Capstu there isn't a pair of shut offs used. My opinion would be to install a pair of ball valve shut offs. I would install the valves in a easy access location one at the closest to engine "out" (upstream location of hot water heater and cabin heater) ,one at closest to the engine "return" ( down stream location of hot water heater and cabin heater. The valves help in isolating coolant leaks, flushing coolant system, and can be used as a emergency shut off in the event of a Heater core failure, hot water exchanger failure or hose failure when on the water. The 2 valves were installed by either Volvo or Cutwater on our boat.
 
Thanks for the replies. Stuart, I read your posts and really feel for you.
Before I posted this, we did pull the heater under the helm out, connections were tight. Also was able to get under the head sink to check those, tight as well. We originally saw small amounts of coolant in the starboard lazarette near the water heater. When we took the boat out, our engine temp went up but we didn’t see a collection of coolant. Later we discovered it had been absorbed by the lines we had on the bottom of the lazarette.
The cap and hose clamp on the coolant recovery tank are tight as well.

The ball valves sound like a great idea. Thanks for the suggestions, Nita
 
Nva, is the coolant level in the exchanger low? How much did you add?

Have you found a way to move the domestic hot water forward or back to gain access to the hose connections?


Stuart Bell
Ranger 25: Shearwater
(561) 352-1796
 
Yes, the coolant level in the heat exchanger was low, added about 3/4 gallon. We have not attempted to move the domestic water heater. We are currently about 20 miles from our slip and plan to return slowly this morning.
 
Just want to be clear about the installation. The Yanmar never had shut off valves for the coolant. This was only done on the Volvo and part of their installation. The cabin heater needs to be inspected which is a matter of unscrewing the four screws on the face and pulling it out. The hot water heater hoses can be accessed and inspected without removing anything other than the panel in the floor in the head. I use a flashlight and stick my head underneath that area to get a visual on it. The hoses can also be tightened from that location.

Hope it is something simple!
 
Nva,

If the coolant level is low and you added coolant, you may have "solved" your problem.

I would try running her "normally" for an hour or so and rechecking the coolant level.

If it is still low, re-add coolant and remove the two hoses on the port side forward on the engine, just above the alternator while protecting the alternator with a plastic bag and rag.

The two parts connected to the fixed engine hoses are called "restrictors" in the Yanmar manual so you can see what you are looking at.

Take both of them off - both ends. The engine end is 3/4" and the heater end is 5/8".

Remove both restrictors from the assembly by removing one from the small hose (about 3/8" hose) and the other from the 5/8" end.

Now connect the two restrictors to the 3/8" hose.

Reconnect the restrictors to the engine - this takes both the domestic hot water heater and the cabin heater and about 15' of hose out of the engine coolant loop while not changing the flow pattern in the engine.

If the coolant no longer disappears, you have a leak in either your domestic hot water heater (or connections), or your cabin heater (or connections).

To find this leak, at home, Home Depot has a PEX fitting labeled 3/4" "L:" for about $3 that connects to the two loose ends of the hot water heater/cabin heater loop. Use a piece of 3/8" hose on this PEX part and connect it to an ordinary tire inflater available free from the Tire Kingdom" trash pile. Pump the heater loop up to pressure and listen for a leak.

When I did this while searching for my engine loss of coolant problem, I found loose or defective hose clamps were causing a fluid leak. I tightened them - the cabin heater was easy, the domestic hot water heater was very, very difficult for me but I'm over 70 and not very flexible. My present plan is to cut a second 5" access opening under the head sink to improve access to the domestic heater.

Anyway, I can send you photos of the pressure insertion tool (the tire valve) if that helps.

I can also photograph the are where you must cap off the heater hoses and send you a photo of the "restrictor" adapter (Yanmar part number 120650-49830 HOSE,RESTRICTOR) if that helps.

Good luck - if you find your engine leak, maybe I can find mine?
 
-Related coolant question when the low coolant alarm goes off.

do you guys wait for complete engine cool down before opening the coolant fill cap?
I was under the impression that the system is under pressure when hot and shouldnt be opened? (even when engine is off)

This situation makes it challenging to add coolant when out for the day. (I just had the coolant changed and i guarantee I will be burping some air bubbles out of the system for a couple of months which will require top ups.)

what do you guys do?
 
You can open the coolant cap part way and vent the steam if necessary.

Under normal operating conditions, the sea water in the heat exchanger cools the coolant to about 190 degrees f in a few minutes of idle running after completing the docking. Look at your coolant temperature - if it is in the 180 to 190 range it is safe to open the cap slowly.
 
We made back to Anacortes today. We ran then engine at about 1700 rpms and the temp stayed at 192 degrees. As we neared the marina, we bumped it up to 2000 rpms and the temp only went up to 194.
After we tied up I pulled the helm area heater out and even tho I had tightened the hose clamps, one had leaked a small amount of fluid, so I tightened it again. I checked the hot water heater coolant hose connections under the head sink. Connections were tight but there was coolant in the area under the shower sump again after I had mopped it dry the other day.
When the engine cooled, we checked the coolant level and needed to add about 8 ounces to bring the level back to where it was when we left this morning.
So, I think the helm heater connection will be ok now, (will monitor it) but still think somehow the water heater or connection is leaking somewhere. I think we must have been a little low on coolant before we left.
Plan to have the boat hauled and water heater investigated.

Thanks for all the helpful suggestions. Stuart, I will post again after we get it checked out. Good luck solving your issue!
Nita
 
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