Coolant leak?

[Russ Calasant]

I have been hunting this coolant leak since I bought the boat. My starboard motor is leaking coolant and it's pooling under the center of the motor. It seems to be increasing, yesterday it was enough to soak four regular paper towels but I have yet to see the coolant level go down. I was first told by Cummins survey mechanic that it was the drain fittings on the turbos then by another Cummins mechanic that it was actually the gasket and the joint where the turbo meets the manifold. I got her home and a third mechanic has now told me that it's not either one and is still looking for the leak. He did find a loose hose clamp that was a contributor but not the source of the leak. Until yesterday the temp gauges were reading 160 under load and I noticed the port was running a little higher at about 162 and the starboard was at about 169 at 2300 rpm but would drop back down to 160 when throttled down and at idle. it is getting warmer out. Thoughts, ideas, suggestions?

 

[Morgan Jane]

Russ, I had a similar situation on one of my QSC's for the last 4 years. Took me that long to figure it out. My problem is technically probably different than yours but it might help you figure out yours. Mine was a slight crack on the back side of the heat exchanger. It would only leak when the system was at engine operating temperature and even then it was only a very small leak but just enough to let you know it existed. The reason for the crack was because the mounting bolts were not torqued down evenly at one point. I removed the heat exchangers and intercoolers at the end of last season to clean them out. And even then, I could only see the crack under a large magnifying glass at room temp. I only figured it out when I went to take off the heat exchanger and one of the bolts was torqued to the max and the other one was basically hand tight. Just a thought.

If you dry yours up at the end of the weekend, is there any leakage that next time you come back to the boat?

Bill

 

[JC3]

Russ, A couple of years ago i started seeing coolant. Could not find it. Finally
one day i was cleaning up and looked at the hoses going to the window defroster.
That is where i found a pin hole leak. JC

 

[Russ Calasant]

Russ, I had a similar situation on one of my QSC's for the last 4 years. Took me that long to figure it out. My problem is technically probably different than yours but it might help you figure out yours. Mine was a slight crack on the back side of the heat exchanger. It would only leak when the system was at engine operating temperature and even then it was only a very small leak but just enough to let you know it existed. The reason for the crack was because the mounting bolts were not torqued down evenly at one point. I removed the heat exchangers and intercoolers at the end of last season to clean them out. And even then, I could only see the crack under a large magnifying glass at room temp. I only figured it out
when I went to take off the heat exchanger and one of the bolts was torqued to the max and the other one was basically hand tight. Just a thought.

If you dry yours up at the end of the weekend, is there any leakage that next time you come back to the boat?

Bill

Bill, that's interesting. No there is no leakage when I come back to the boat or when I run her at the dock. I idle down the river for a half hour to get out and in, there is no leakage then either. I will check and see if I can get a better look at that heat exchanger.
There is probably half a cup maybe less in a puddle and I think it's hitting the prop shaft because I can see splatter spray coming out. Also I have been checking coolant level and it does not seem to be dropping. I cannot find any evidence

 

[Russ Calasant]

Russ, A couple of years ago i started seeing coolant. Could not find it. Finally
one day i was cleaning up and looked at the hoses going to the window defroster.
That is where i found a pin hole leak. JC

You have a window defroster? It uses coolant?

 

[JC3]

Yes & Yes! Or you could call it a cockpit heater. Any way the leak was found in the compartment beside the captains chair. The fluid was running down the hose
ending up in the engine room. Good luck, JC

 

[Russ Calasant]

Yes & Yes! Or you could call it a cockpit heater. Any way the leak was found in the compartment beside the captains chair. The fluid was running down the hose
ending up in the engine room. Good luck, JC

Ah, okay, I had one in my 370 but not the 460. Probably would not have thought of it if I had one though, good call. Thanks.

 

[Russ Calasant]

I did check the heat exchanger today and cannot find any leakage evidence. The saga continues. I think my best shot is to run her and climb in and look around while running hot.

 

[Russ Calasant]

Okay, I got the mechanic to come out for a ride and we found it! It is in fact leaking only when the turbo spools up at the flange! The second mechanic was right and now the third is convinced. I must disclose that the only reason my current mechanic was not convinced was because Cummins told him the odds were slim and none. I guess slim won. He is replacing the gasket next week, I will let you know how it works out.

 

[Alex F]

Hey Russ, I'm glad you finally found it cause. I guess Chuck deserves some credit if he was able to point this out without running her.

I wonder what lead to the leak, just the age of the gasket or is there something else?

 

[Russ Calasant]

Alex, yes he does and I told him. I'm not sure how he knew without running her. I think it was just gasket failure but I will know better next week.
Off to Block this weekend, what are you guys doing?

 

[Alex F]

We're cruising local grounds for now, but wishing to be at the Block and surrounding area. Is August here yet? I can't wait to burn substantial amount of fuel...LOL.

 

[Russ Calasant]

I know it I have already burned 700 gallons!