2013 R25 Coolant Leak

[GigPilot]

So I have been trying to troubleshoot a coolant leak. We keep the boat in the water year around. Over the winter I would go down and run the engine every couple of weeks. One of the days I got the low coolant alarm. After reading about the Volvo D3, I just thought the sensor was being sensitive and added a little coolant.

After I had a diesel mechanic change the timing belt, he noticed the coolant expansion tank bolt on top was pretty rusted. It was suggested that the tank might be cracked and should be replaced. I ordered a new tank and other parts. When I was replacing the tank, the top bolt was so stripped out and rusted (along with really hard to get at), it could not be removed. I kept the parts for a future job. Since I had to drain the coolant (and not sure when it was done last), I replaced with new coolant. The engine ran great and was two degrees cooler than before.

We took the boat out a few times on day trips with no issues. A couple of weeks ago, we took a 3-day trip. On the pre-departure check, all the fluids looked good. The first leg was about 4 hrs. On the day 2 pre-inspection, I noticed some drops of coolant by the port aft engine mount. I added some more coolant. I looked at the lines and did not see anything that would indicate a leak. When looking in the expansion tank, the fluid looked good. But when we went to start, the low coolant alarm went off.

We continued with the trip, adding about 12 more hrs and did not notice anything unusual. Yesterday when I was looking through the starboard aft locker, I noticed what looked like coolant. I cleaned it up wondering where it came from and later recalled that the coolant goes to the water heater and cabin heater. I was suspecting a line leak. Today I checked and there was still some coolant by the water heater, even after the cleanup the day before.

So today I ran the engine up to temp and warmed up the water and heater via the engine. No visible leaks in the lines or by the water heater. So the question I have, has the water heater failed and is now leaking somehow? I poured some hot water into a cup and did a smell test. I did not smell any coolant in the hot water, but then again, my sniffer is old! Any thoughts?

Thanks,

 

[Chimo]

Check on the port side of the engine. There are two ball valves. I believe (can someone confirm please) these will shut off the cooing circuit that goes to the heater and water heater. If correct closing them will allow you to isolate that part of the circuit. If you still have a leak with them closed it’s not from that segment.

Hope this helps.

 

[GigPilot]

I did see the two ball valves and was not sure if those were for maintenance only?

 

[Chimo]

I confirmed with the dealer that I was correct. You can run the boat with the valves closed without problem. Good luck with the trouble shooting.

 

[GigPilot]

I confirmed with the dealer that I was correct. You can run the boat with the valves closed without problem. Good luck with the trouble shooting.

Thanks for the update. I’ll give that it a try and see if I can isolate the problem.

 

[dclagett]

I had a similar problem with my 2014 RT25SC. Turned out to be loose hose clamps on the coolant lines in the front of the water heater. Very hard to get at. Used a small ratchet with appropriate socket reaching the clamps through the head cabinet. Make sure you have on a long sleeve shirt to minimize scratches and cuts form fiberglass.

I would suggest you purchase a endoscope/borescope for looking into areas such as this. They have been very helpful for me in the maintenance of my boat. Very reasonable cost from $30 up depending on screen size and fidelity.

Good luck!

 

[2islanders]

My 2012 RT25sc had the same leak on the hot water tank. I also purchased a Mityvac MV 4560 cooling system pressure tester off Amazon so I could actually see if the leaking was resolved, easy to use and you can look around while it’s all cool and quiet.


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[Texas Tuggernaut]

After finding coolant under the water heater in our 2013 R27 I replaced the water heater. It was 10 years old and I figured the coolant loop was leaking. New heater works fine with no more coolant losses.


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[2islanders]

Yes, I had the same thing, pink liquid (antifreeze) leaking out from under the heater. I was just about to buy a new one, took it out and decided to have one last look with the pressure tester. The hot water tank tested fine and finally figured out the leaking hose in the back fitting saturated the insulation and was the culprit. Dried it out and put it back in with new clamps and still good with no more problems.


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[GigPilot]

I was able to get in there today and tighten the 4 clamps. I’ll see how it goes. If it is still leaking, I’ll try the pressure test and then just replace the water heater. It is 11 yrs old, so that might be the issue.

 

[GigPilot]

After a couple hour run, the leak came back. Today I was able to replace the water heater. I ended up following the guidance on the site (Thanks everyone!)

I was concerned about taking off the coolant lines and having coolant everywhere! That was not an issue. The hardest part was getting the new tank in. I had to remove the water pump and battery charger. The old one came out with no clearance to spare. The new one was the same size, but would not go in. So I took the cover off and it popped right in. I used a fishing camera to help with the install of the coolant lines. That helped a lot to see that the lines were all the way on and the clamps were in the right place. All in all, not too bad of a DIY job. Took about 3 hrs and would have been less if I would have just dove in. Also I should have worn a long sleeve shirt, but it was hot today so I have some cuts.

When I got home, I took the old tank apart. The insulation on the bottom was soaked in coolant. So it was time for a new one.

Now to get back to cruising!

Cheers