After cooler condensate drain

[BrisHamish]

Good morning from Brisbane, Australia!

It was a cool-ish winter morning here, few rain squalls early on, but it calmed by 8am and I took my GB46 out for a sea trial with the prop guy. Ran at WOT, doesn’t quite make full rpm, need to take some pitch out. All good.

Upon my return to dock however I noticed some water at the bottom of the starboard aftercooler condensate drain. Port had a little as well, but it is harder to access. I have never seen any there before, but then I haven’t always looked either. I will try to attach phots. It was maybe a cup or so (say 500mls to 800mls). I tasted it, it was very slightly salty but nowhere near as salty as seawater (I did an immediate taste comparison!).

Thoughts? Could this just be a cold morning, and running engines at 100%, creating some condensate??

H.

 

[sum escape]

I get a little drainage from my Cat C-9s occasionally too. And I do not look every trip either so I am not sure if cold weather is the cause.

 

[sunchaser]

H

What engine year and model? Is the port motor behaving the same but less drainage? Also, when was last time after coolers were pulled, cleaned and pressure checked? Are the coolers raw water or jacket water cooled?

Slightly salty could mean many things. Have you looked at both sides of the turbo?

 

[Ski in NC]

Looks like a QSC Cummins. Normal for condensate to form in aftercooler when running at power. With boost up, drain valve is closed. When you come off power (and boost) valve opens and the condensate dribbles out. Valve closes with pressure and opens when pressure is gone.

Should not be salty, though.

 

[DavidM]

I agree with Ski. But you should do some more investigation into the source of the salty water. An easy way is to do an oil analysis and look for high sodium which is a strong indication of a failing sea water cooled after cooler.

Even better and should be done in any case is to remove, disassemble, clean, reassemble with new o-rings with lots of grease and pressure test. If the after cooler is leaking the cause should be readily evident when you disassemble and look at the shell to tube sheet joint. If you find significant corrosion then that is probably the cause of your salty condensate.

Fix it soon as it isn't doing your engine any good.

David

 

[BrisHamish]

Thanks guys.

Engines are 2006 CAT C7 ACERT, aftercooler Cores replaced and raw water loop flushed with Rydlyme less than 50 hours ago, was leaked tested at rpm when that work was done.

Was only very slightly salty taste to the water, am wondering whether that is just the salt air crystals on the ER floor. If the aftercooler core or a gasket was busted I would have thought it would’ve proper salt water.

Won’t run them again until I can get the CAT guy out to look. I spoke to him, he was alarmed.

Personally I am leaning towards it being condensate, but am nevertheless cautious and was interested in your knowledge/views/thoughts.

Thanks,

Hamish.

 

[DavidM]

Try to catch a sample directly from the condensate drain and taste it. If salty I would pressure test again.


David

 

[BrisHamish]

That is an excellent idea. Will get a clean milk bottle and idle it to catch some. H.

 

[BrisHamish]

Thanks again all for your thoughts.

Interested to hear that your C9s have some water from time to time Sum Escape. They are somewhat similar vintage to my C7s.

Ski, your comment about a drain valve on the Cummins is also true for these CAT engines it seems. The CAT mechanic wants me to remove the valve (which connects onto the black drainage pipe you can see in the photo), then idle the engine and see if liquid comes out. If it does, I will catch it in a clean container to check if salty (thanks DJ). Will then do the same on port side.

I will run this test tomorrow am my time and let you all know how it goes.

Thanks again!

HA.

 

[sunchaser]

Why were AC cores replaced? If seals and gaskets not prepped with Cat’s recommended grease a tight fit may not have occurred allowing some salt water to mix with condensate. Be very careful (better yet don’t do it) using acid cleaners on ACs. Cat’s AC builders have not been religious in following specs regarding solders and weldments with some cleaners rotting them out.

Back to previous questions, what do both sides of the turbo look like and are you 100% sure the ACs are salt water cooled?

 

[BrisHamish]

Sunchaser, cores replaced as per CAT service manual as they were 6 years old. No leaks, I have kept the old ones as spares. All work done by CAT, all parts genuine.

More generally, my eldest son and I ran my test this morning and good news I think. There is no sign of salt corrosion around the valve drain plug, and at idle no water came out the drain hole. See photos. I stuck my small finger into the drain hole and there was a droplet of water, it tasted fresh no salt at all.

Will continue to monitor by placing a clean milk bottle under the condensate drain.

thanks all!

Hamish.