6CTA8.3m Overheat issue

[Bob Bonser]

I am knocking my head against the wall here. Any suggestions welcome.
Heres the timeline of this issue.

1. 4mos ago an impeller failed underway. Overheat to 210, I replaced the impeller at sea and all was fine

2. 2 mos ago I had the serpentine belt fail, Overheat to 210, replaced the belt at sea, all fine

3. 1 month ago random overheat at sea, towed in
a. I had some parts, all new so I replaced the fresh water pump, sea water pump and impeller, new serpentine, new thermostats, I removed the intercooler, opened top and bottom. I fished out the old rubber from the initial overheat issue. There was no corrosion on the tubes or fins from what I could see, Put it all back together.

4. Boat runs smooth, no oil in water, no water in the oil. Anti freeze 50/50 stuff from cummins (complete?) No smoke

5. temp gradually rises to 210

6. All the hoses on the sea water, intercooler side are cool , 80deg or so

7. Hoses on the heat exchanger side are empty till the thermostat opens at 180. then they get full and temps there match the temp guage. It seems like once open, the overheating rate rise remains constant. clicking up a degree at a time till alarm.

8. I used a laser to shoot the hoses. the thermo outlet hose enters the heat exchanger and the rearmost hose out the bottom tends to be as much as 130 deg cooler.

I haven’t opened the heat exchanger yet. Its the only part I haven’t inspected. Any ideas? I feel I checked and did everything. Air temps here are ok in the 80’s and sea temps are low 70’s

I am trying hard not to have a cummins tech out as that will be a $1000. I believe that the guage is correct because the numbers are matching what my laser is reading.

Thanks,
Bob

Topic

[Tony Athens]

Turbo leaking issues

Bob,

Any good with a camera?

Let’s drain the coolant down, get all apart and get all clean. Buy a composit gasket from Brad and 4 new studs and nuts. Display all so I can SEE EVERYTHING and I’ll walk you thru it.. Something is not right and I do not belieive the right gasket and assembly will not put this behind you.

Tony

[Bob Bonser]

turbo gasket

Tony,
After reading your article about the manifold to turbo gasket change I did some more investigation. My manifold, at the mounting surface, at the lower 1/2 is showing signs of pitting and rust. Hitting it with a wire brush cleaned it up some but nothing shiny by any stretch. The mounting surface for the turbo itself is clean, shiny and without blemish.

I did not do the gasket that sits on top of the exhaust manifold, when I do the turbo gasket again I can do that one also.

I reinstalled the turbo gasket, using the same new one that I installed from yesterday, I used the red RTV and let it sit overnight. I just sea trialed here are the results.

1. Zero drippage from turbo gasket at idle for 45 minutes and no reduction in coolant. Coolant (water at this point) was right up to the filler neck before and after.

2. got the boat to 165 (thermostat open) and I ran the boat at 2200rpm for 20 minutes. No temp change.

3. While underway I looked at the turbo and there is a steady stream of water coming from the center of the turbo mount directly between the two lower bolts. I guess its possible that the water was coming from above those bolts and collecting there but I couldn’t see any leakage from the coolant hoses, nor obvious cracks in the turbo housing.

4. After this 20 minute test I found that I lost a little less than one gallon. This seems about right for that leak. And is half the amount of loss that I incurred with the prior sea trial before the reinstall of the turbo gasket with RTV. This is making me have a little hope that the problem is at this location.

5. At this point I am unclear. I realize I could pull the exhaust manifold and get the surface milled, or at that point replace it with new. I really don’t want to pull that manifold. I can only imagine studs and bolts snapping and stripping!

6. In your article about replacing the gasket you mentioned using a composite gasket if there was pitting.

7. Are you still in favor of trying a composite gasket? If so, do I make it or can you supply? If not, what do you suggest?

Thank you again,
Bob

[Bob Bonser]

turbo

I just looked at your article related to the turbo gasket change and the SBMAR way! I wish I would have read that before I did the job. I now need to redo it. I have a leak at the lower edge, if its leaking there theres no telling whats going on where I can’t see.

I will redo the gasket the right way and report. The surfaces look clean and unpitted to me but I can’t check it for trueness.

Pressure test of the coolant system once I can find the tool.

Thanks Tony

[Tony Athens]

Top of manifold gasket? Same as the turbo gasket.

New 160F stats?

Checked seawater pressure and vacuum at the pump?

A solid pressure test of the coolant system ?–Both hot & cold? Both very lttle coolant and full?

Put special dye in the coolant and looked that the exhaust outlet with a infra red gun?

Lots of things to do before I’d pull a head, especially with two things going on that are only indirectly related…

????????????????

Tony

[Bob Bonser]

Head exploding (my head)

Ok men. Thanks for all the help to here. After having the, aftercooler, heat exchanger, oil cooler serviced by a Ron Jago we are still overheating and still losing coolant.

Ron suggested the turbo gasket which I replaced, which did not correct the problem. Boat runs great for 30 mins then heat creeps up. Shut it down and check and we have lost about 3gal of Coolant.

It seems that at this point only the head gasket and exhaust manifold are left to blame. I don’t know how to diagnose. There is zero loss at idle even after an hour. (If that means anything to anyone)

Any ideas?

Thank you,
Bob Bonser

[Tony Athens]

Thanks……….I lost track on this one..

Tony

[Corey Schmidt]

Hoses

Send a note to [email protected] with your serial number and he can sort you out on replacing your engine hoses…

[Tony Athens]

My input???

Is this a new thread based on an earlier one?

I am lost here–sorry!

Tony

[Bob Bonser]

Overheat and sea water

Tony,

Once again thank you for all your input. I am thinking that since the HX, gear and intercooler are out I should replace all hoses. They are all at three years old and maybe 500 hours.

The main hose from the sea cock to the sea water pump. This hose is 7 years old.

2 inch wet exhaust hose. With or without wire? Corrugated? Something else all together?

Do we have a kit that contains all the sea water and fresh water hoses? They are all kinda small but I am sure not kinda cheap!

Thanks
Bob

[Bob Bonser]

Hx and intercooler

Thanks for the pictures. I will be hoping for similar results. Next week I will update.
Thanks
Bob

[Rob Schepis]

Heat-X Cleaning

Here’s some pics (Before / During / After) from last year when I did the genset heat-x servicing and cleaned just as Tony explained above

[Tony Athens]

Heat-X : Stand it up on ONE end –Remove and plug the zinc hole. fill it up with 10 parts water & one part common pool acid/HCL, and let it “bubble” for 30 minutes to an hour.. That will remove the scale that builds up on the inside walls of the tubes ( you cannot see that or remove it any other way)..

On the coolant side, just rinse it out with a hose unless the outsides of the tubes look like they are oil coated.. Then fill that side up with some type of degreaser or alkaline based cleaner & try and clean it that way before rinsing.

Service the aftercooler per the articles on this web site.

Take off the seawater pump and inspect (remove them) the impeller, inner wear plate , cam & housing bore.. IMO, You cannot do that properly on the engine very easily.

Gear cooler– same as HX–You need to “bubble” the inside tubes

Tony

[Bob Bonser]

Heat exchanger

Pulled the Heat exchanger and the intercooler and the gear cooler. I took the ends off the heat exchanger. Nothing earth shattering in there. A few pieces of the old impeller made it through. I can’t see this thing being the source of our problem. The other thing I found out is that my intercooler is only three years old. Ron, told me he purchased it new and installed it when he did my last service on my engine. I hope this overheat problem goes away.

[Bob Bonser]

Props

Thank you Corey. Cooling system getting pulled and serviced. Then the proper propping!

Bob

[Corey Schmidt]

Bob Bonser wrote:

I have been reading regarding propping. Props move boats engines turn them, and Propping the Cummins 6CTA 8.3 480CE vs. 430/450 Diamond Engine.

I am trying to grasp this thinking.

A motor creates hp, but that can be manipulated with different props?

If my engines makes 2650 at 23gals and 100% load this is overpropped? I should or want to make 2750 at 90% load or 2200 rpm @ 13.6 gph.

Must both of these benchmarks be met or is one or the other acceptable?

Bob,

The PROP is the only thing providing load to the engine, think about the difference in how the boat would move if you spun two different size props the same RPM on your boat, let’s say one prop is 10″ square and the other is 25″ square. Let’s say they both spin at 2200 RPM which would be a typical cruise RPM.

How much fuel would the engine need to burn to spin the 10″ prop as opposed to the 25″ prop? Much less, right?
What would the difference in overall boat speed be?

The entire point of the propping article is that you need to choose the correct size propeller so that the engine burns no more that 13.6 gallons per hour at 2200 RPM, the rest takes care of itself, it’s that simple.

When you get all of the cooling components back or replaced after assessment and/or cleaning, you can go for a run and check your current fuel burn at 2200 RPM, then we can make a decision on how much prop pitch to remove to achieve that 13.6 GPH goal.

[Bob Bonser]

Ron

Tony,

Ron told me to send his regards. Just got off the phone, he in fact is the guy who went through my motor. He put your water pump on it, and serviced the hx and intercooler. Mentioned that he lubed them up the way you like it done.

I am getting my cooling system, intercooler, hx, and trans cooler to him this week. I will post our finding if you think there is value in it.

Thank you,
Bob Bonser

[Bob Bonser]

Ron jago

Lol. Ron is the guy who pulled the engine and serviced it. Boat was in palmetto at the time!

I haven’t talked to him since then Because we moved the boat to St Pete. Now we are using Cummins Southeastern Marine power.

Maybe there is hope!

[Bob Bonser]

Props

I have been reading regarding propping. Props move boats engines turn them, and Propping the Cummins 6CTA 8.3 480CE vs. 430/450 Diamond Engine.

I am trying to grasp this thinking.

A motor creates hp, but that can be manipulated with different props?

If my engines makes 2650 at 23gals and 100% load this is overpropped? I should or want to make 2750 at 90% load or 2200 rpm @ 13.6 gph.

Must both of these benchmarks be met or is one or the other acceptable?

Tony’s article mentions that the damage to these motors is done and Cruise rather than WOT. What is considered cruise ? I could not see that noted on any of the charts.

Once again I thank you so much for your time.

[Tony Athens]

Engine hours are not the issue—-It’s “Marine Age”.. Look that up on this web site

“A typical Cummins guy” 90%+ they did not do it right…

Build a long term “wood box”–many guys do that–That way you’ll save money as we use it too and you can save it for down the road and maybe hook up with some other guys and share it.. Lots of your types of aftercoolers & HX’s in your area..

Plus, there is “Ron Jago” in Bradenton– He’s good — http://www.unlimitedyachtservices.com/about.html

Tony

[Bob Bonser]

Servic

Tony as always thanks, but I did mention that both units were serviced by a Cummins guy 2-2.5 years ago. Haven’t had many hours these last 2 years.

I only took off the end caps to get all the old impeller out, and I only looked cause of this new overheat, so there is maybe 1 hour since then. Perhaps disaster is still at bay.

Let me get this hx off and sent out for service, intercooler too. If Tampa Cummins can’t do it I can box it and ship to you. The problem there is a week UPS both ways and then your shop time. I will be down for three weeks.

Once I get the overheating under control, then I can figure out if my prop is too heavy.

In your opinion, is this an OK plan?

[Author]

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