Black coolant?

[Jen Wren]

We put more than a 1000 hours on our QSC 540’s every year.  Just to be safe I service the heat exchangers and aftercoolers every year per Tony’s tips with Metal-lube and so on.

I am just draining out the green coolant we put in this spring and it is now as black a coal.  Does anybody have any ideas what would cause this?

Topic

[Tony Athens]

Thanks for the follow-up & validation of my comments…………………………….When I got involved with a “Cummins Marine Diesel Help Forums”, about 17 yrs ago with Boatdiesel.com , my intentions were to help & share experiences and that would build and then others would see and do the same thing………..Well I think I accomplished all of that for the time I was there, but about 2 years ago, the politics of what we started with took on a different “flavor”……………..All of a sudden, it became membership fees and advertising were the #1 purpose of the BD………….

Anyway, you can take it from there.. We are here to help as we can and the more we can, the more will come into these forums from others with solid “field experience knowledge & experiences “, and it just blossom from there————————–That is really what forums like this should be about–

Not about fees and advertising dollars…………………………..Should something come out way sales wise, that is truly appreciated, but that is not our intent………..

Thanks,

Tony

[Jen Wren]

Test

[Jen Wren]

Paying it forward

Tony, you are 100% correct.  In the spring I purchased the $2K silicon damper.  My aprahention was the folks that sold it to me said most likely it was not the cause of my vibration.  With that I have sat on the damper all season waiting and watching.

By coincidence a friend just took delivery of an almost identical boat in Florida.  Turned out he had the same vibration.  Cummins in Florida diagnosed it was the damper.  The bid to replace it included 30hrs labor but only $500 for a new damper.  They told him that ZF has replaced the old damper with a new softer one.  It wasn’t until Cummins got the green light that they advised it would be an additional $1000 to have ZF come remove the splined hub.

The new damper solved my friends vibration problem.  With that I decided to go ahead and change mine.

If I had it to do over I would have purchased the part from you.  Your forum is invaluable and a wealth of knowledge.  My intent was to inform others they would be opening a Pandora’s box if they tried to remove the hub.

[Tony Athens]

You DO NOT need to remove the splined hub from the transmission input shaft using a $5000 KKF Hydraulic puller–I do not know where you are getting your input, but they are 100% clueless———————-You just need a NEW SILICON Damper assembly– Simple replacement..

Drop me note direct if you zero out  looking locally. We stock what you need..

 

Tony

[Jen Wren]

Follow-up with better pix

At first inspection this dampening coupler looked good to me.  I expected damage to be at least a little obvious when we removed it.

Upon closer inspection I did find cracks in the rubber.

Here are a couple closer shots

The boat is going to remain in dry dock until after the first of the year but I’m pretty sure these subtle cracks are what was causing our vibration.

Here is a good tip for forum members.

Don’t try this one at home!

It takes a special ZF tool to remove the splined fitting or adapter (not sure of correct terminology) from the tranny shaft.  ZF charges crazy money to remove it and for the un-knowing it doesn’t look that tough.  What appears to be a set screw is where a ZF hydraulic pump is connected.  Pressure is exerted with fluid to remove it.  Be aware trying to do it yourself could be an expensive lesson.

 

[Rob Schepis]

More & Better Pics..

We’ll never say no to more or better pics..

[Jen Wren]

Found it!!!

Rob, Thanks for asking for photos.  In the process I found cracks in the old coupler.  These pix leave a lot to be desired but you can see the cracks in 2 photos down in the cavity.

Heading out now to Gringolandia to spend the holiday with family. Can post better photos next week if you would like a more clear illustration.

 

[Jen Wren]

Rob,  In April we snapped a shaft and had a new one built in San Diego matched to a new coupler.  Also bought new props.  Since then I found a brand new Cabo Yachts Aquamet 22 shaft from the factory.  I have had it checked, polished and matched to my old coupler.  We are intalling it today.  Also I didn’t like the new props and the shop swaped them for a different brand new set.  That is another story if you are looking for a great prop shop in SW Los Angeles.

 

The deal is we had this vibration before snaping a shaft but now it seems to be getting a little worse.  Cummins said live with it.  It is not horrible but not right.  I would rather act then have to react.   One thing I just thought about is that when using the trolling valves there is no vibration.  Seems like easing into gear rather then banging in a 660rpm makes a difference.  In my uneducated mind that leads to the dampener.  I inspected the old dampener very closely and it looks physically identical to the new one.  I expected to see some sign of failure or fatigue.  Maybe 8000 hours of having 540hp bang on the dampener has taken its toll and I just can’t see it.

The boat is going to remain on the hard for the next couple months and the antisipation is already killing me.  I will post some photos

[Rob Schepis]

Coupler….Pictures ?

Post some good pics of the coupler assembly

[Rob Schepis]

Vibration

Since you have the gear separated sounds like it would be easy enough at this point to take the shaft and coupler to the prop shop (machine shop) and have it checked for true-ness, coupler fit & faced, prop checked, etc..

[Jen Wren]

Sorry for the confusion on this.  I said manifold gasket meaning turbo to manifold .  My photos were not the best but did illustrate and confirm a small leak.  Over a 1000 hours it did contaminate the coolant.  We make a practice of always using the red RTV and was surprised to find it absent.  Must have been distracted when assembling.

 

Unrelated, we did crack the gear from the motor and remove the dampener coupler today.  To my dismay it appeared to be in perfect condition.  We installed a new one but I fear it might not solve our idle vibration in that motor. The motor sure has the symptoms of a bad coupler.

[Tony Athens]

That’s what I think..

 

Tony

[Larry Backman]

Soot made it black?

just making sure I understand correctly?   The turbo gasket was not correctly sealed and soot from the exhaust penetrated into the coolant?

 

 

[Rob Schepis]

Thanks for following this through.  I R&R’d my turbos last year.  The gasket and manifold looked good.  I reinstalled the Seaboard way with new gasket and red RTV.  100% a-okay.  When you use the red RTV let it ooze out but don’t clean up the excess til it’s cured..

[Jen Wren]

Many of these threads just die without the members knowing if the victims issue was resolved. I want to follow up.

It makes sense that Tony’s assessment is right on.  A fact not mentioned because I didn’t think it was revenant is that in the spring we replaced both turbos.  Apparently the manifold gasket didn’t seat good.

I mentioned we were replacing the dampener coupling.  Yersterday we split the turbo to make room to raise the motor. I never would have found our issue.

 

Our leak isn’t as obvious as Tony’s illustration but sill there.

Heat exchanger and coolers all in a heap.  It is not rocket science.  Don’t be afraid to tackle your own service per Tony’s tips.  He goes step by step and explains so anyone can do it.

3 users thanked author for this post.

Peter McKibbin, David Wesner, Corey Schmidt

[Jen Wren]

Thanks Tony.  I owe you again.

[Tony Athens]

Do this on this suspect engine.. Under $50 and a few hours..

 

Tony

 

 

 

 

[Jen Wren]

A little more history.  The motor preformed perfectly all year and had nothing but normal service i.e. oil, filters and zincs.  Last month I did notice the reserve coolant tank was empty and filled it.  The motor never showed temerature. Even running full throttle for 30 minutes a couple of times while fishing tournaments it never pulled more than 176 degrees in 85-87 degree water.

That said it does have an issue I feel unrelated.  It vibrates at idle but goes away when kicked up 20 or 30 RPM and has done it all season.  Had Cummins out last month.  They found nothing accept the lift pump is drawing higher than normal voltage.  Motors have 8K hours and I am changing both lift pumps.

Took Cummins for a test and when the motors hit 2670 RPM without a grunt, their hair was flying and we doing 34 knots they said just drive it.

No where to go with the low RPM vibration I am changing the dampener coupler and that is how I discovered the black coolant.  It is jet balck but has no oil.

We run hard and I am in the engine room everyday looking for anything that doesn’t look right.  Combustion gas in my fresh water is the fear but from where?  Motor runs like a striped ape and shows no other symptoms.

[Rob Schepis]

It sounds like all was okay other than the surprise you found when draining the coolant? So..No overheats?  No water in oil?  No oil in the steel coolant tank or in the plastic overflow bottle?

[Tony Athens]

Are you 100% you are not leaving anything out of the history since spring?  Loss of coolant, or ?..

There are really only three things that would cause this–Oil, combustion gases, or exhaust getting into the coolant and all of these would typically cause something external to be noticed?

Have you mixed mixed coolant types?.

Total hours?

 

Tony

[Author]

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