RT D3 Volvo using cooling fluid

[Les Blackwell]

I have a 2018 Ranger Tug 25SC with a D3 Volvo 150 motor. I am not a motor person having been a sailor most of my life. I am getting use to this big motor however....I seem to need to fill up the cooling fluid tank before i go out each time. I remove the upper outlet fitting, then reach under to get the main tank opening. With a good light I peer in and most of the time it is empty. So I have a tall funnel and I fill the filling tank up. I have gone through six gallons of antifreeze or cooling fluid

I have had a volvo dealer check out my engine and there are no leaks. I do not see anything coming out with the outflow water from the engine and there is no fluid in the bilge. We've check the hot water header and the Webasto heater for leaks.

First, do any you RT have the same problem or concern? Is this normal? Where could the cooling fluid be going?

My next thought is to have the Volvo dealer do what is called a pressure check on the engine.

Any thoughts to help me? Thank you.

 

[BB marine]

It is not normal, You should not have to add coolant of that amount. Initially you may add a small amount because of air in the system. It is a closed system. Area's to look for coolant leakage would be around hot water heater inspect hose clamps and coolant hose for coolant, next follow the coolant hose to the "bus heater" in cabin inspect hose , clamps and heater core for visual leaks. Check coolant reservoir for cracks or leaks at hose fittings. The coolant is used to cool the block, exhaust manifold, engine oil cooler, and is cooled when passing through the heat exchanger. The coolant can leak externally or internally from each component. External leaks can be found by visual inspection, looking for puddling, or drips. Some times using a paper towel or absorbent towel will aid in finding a hidden external leak. Internal leaks can be harder to find and your suggestion of having the closed cool system pressure checked would be advisable if no external leaks can be found. Six gallons is a lot of coolant. It should be visually seen if external. The D3 coolant capacity is just over 3 gallons so adding 6 gallons is a significant coolant leak. A leak of this magnitude should have alerted the Volvo dealer to have checked more thoroughly. ( my opinion ) Adding a little coolant is not unusual because of a clamp or fitting leaking. Adding 6 gallons is an issue.

 

[TomFin]

I agree with Brian. In 2 years of boating our D3 has had maybe 1 or 2 quarts of coolant added total which i think may be a small leak at the hot water heater.

 

[Cutwater28GG]

also check the heater connection in the cabin.

its worth testing every single hose clamp on every single coolant pipe. when these engines are run up at speed the pressures increase and by the time you check later its all dried up. its hard to see the color residue.

 

[Automaticman865]

I dont know if the D3 has the same setup as the D4. It has two shutoffs on the engine which will bypass the hot water and if so it will help diagnose the leak.

Stuart

 

[Chimo]

We have a 2017 version of the same boat/engine. When we first bought it we had a “burp” that dropped the coolant level and caused a warning from the Volvo electronics. It’s very hard to see the actual level in the expansion tank so I topped it up and then let the relief cap lose the excess as the engine ran. I tried checking level later but, as I said, it’s not easy to see. After 320 hours of running I’ve never added coolant. I do carry a gallon onboard just in case. Have you had a low coolant warning? Are you sure that you’re not simply losing the expansion fluid that is then pumped overboard from the bilge?

Just a thought.

 

[Newf]

I had a much smaller leak on my D1-30 VP and traced it down to the two connection on the cabin heater. Would recommend tracing and snugging up the hose clamps on all of your connections. I had some that easily took a full turn and the screw.