Official Caterpillar3116/3126 Thread

gmaki said:
Hello again. My first of many mundane questions now that I have full possession of the boat.

My overhead lights are not illuminating on the radar arch. Seems like all other cockpit and salon lights work fine.

What I am trying to figure out is which switch should control those lights. My best guess is the cockpit lights switch at the back of the cockpit. And if that is the correct switch, any idea why those lights won't come on?
Click to expand...

cockpit light switches controls the low courtesy lights and the switch on the helm marked 'spoiler lights' turns on the overhead

PS: this is the CAT engine thread, these questions are best in the 400/410 owners thread
 
I spent some time today studying the heat exchangers on my 3126s. I've done some research on how they work, and it makes sense to me. Looking at my port motor, the heat exchanger cap on the inside has two hoses, one's coming off the raw water pump so that's raw water in. I assume the second one is raw water out as it goes to the transmission cooler. Then I assume the one hose on the bottom of the other side, is for coolant to circulate around the engine. Am I correct so far?

I only saw one hose on the other side, how does coolant circulate?

,
 
mrsrobinson said:
I spent some time today studying the heat exchangers on my 3126s. I've done some research on how they work, and it makes sense to me. Looking at my port motor, the heat exchanger cap on the inside has two hoses, one's coming off the raw water pump so that's raw water in. I assume the second one is raw water out as it goes to the transmission cooler. Then I assume the one hose on the bottom of the other side, is for coolant to circulate around the engine. Am I correct so far?

I only saw one hose on the other side, how does coolant circulate?

,
Click to expand...
 

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  • CAT_3126_HEX.png
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I have that diagram though it doesn't help me understand the flow of water/coolant. That is what I want to understand.

Looking at the pic:

  • Looks like coolant comes in from the top/expansion tank on the right
  • then comes back out of the bottom left
  • Looks like raw water comes in and out from the right side view?
 
same flow as a car

when the coolant is hot enough, the thermostat opens, allows hot coolant to flow into the radiator (HEX)

flows out of the radiator (HEX) to the water pump
 
Maybe A Dancer said:
same flow as a car

when the coolant is hot enough, the thermostat opens, allows hot coolant to flow into the radiator (HEX)

flows out of the radiator (HEX) to the water pump
Click to expand...
With a car there are only 2 hoses though, top of radiator and bottom, air does the rest.

It's my understanding the raw water enters and exits from the right side of the diagram, the port inside HEX cap on my boat. The water moves thru tubes (in then out) and the heat from the coolant is captured in the "out" water to remove the heat. Where the raw water on the boat replaces the air for a car radiator.

Am I close?
 
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mrsrobinson said:
With a car there are only 2 hoses though, top of radiator and bottom, air does the rest.
Click to expand...
===================

The car radiator is a water to air heat exchanger

The HEX on a boat is a water to water heat exchanger

Same concept, different medium

RWS
 
Has anyone experienced this ? The oil you see in the picture... Just tighten up the oil pan bolts ?
2022-08-21 10.46.53.jpg
 
My stbd engine had oil leaks coming from the side cover gasket.

I found the bolts to be SURPRISINGLY LOOSE.

Snugged them up - not too tight

NO MORE OIL LEAK

BEST !

RWS
 
I don't have this, but agree, maybe cleaning up and try tightening them to see if it stops the leak(s). Some of my bolts are ridiculously tight and some are looser than I expect. I suspect that's years of different folks working on the engine.
 
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Hi Guys,

I have a pair of 1997 3126 MUI 420Hp cats.

I purchased the vessel in Feb, it was a lake boat its whole life > now in salt water.

They run great, I am super happy with the engines.

1050 Hrs Each

I Have been trying to learn as much as I can about these puppies and how to keep them purring for a long time.

Besides the obvious, oil changes

What else can I do to stay ontop of maintenace?

I plan on replacing the Zincs religiously. I have the service manual but is there a place that outlines where they are on the aftercooler? Im having a bit of trouble finding a resource for that?

Beyond that, i've heard staying ontop of the aftercoolers themselves is a big service item, Should I have them pulled, inspected and pressure tested? What happens if there is an issue? where do you get replacements?

Any other tips you would care to share?

Many thanks.

-Nate in Vancouver
 
NateVancouver said:
Hi Guys,

I have a pair of 1997 3126 MUI 420Hp cats.

I purchased the vessel in Feb, it was a lake boat its whole life > now in salt water.

They run great, I am super happy with the engines.

1050 Hrs Each

I Have been trying to learn as much as I can about these puppies and how to keep them purring for a long time.

Besides the obvious, oil changes

What else can I do to stay ontop of maintenace?

I plan on replacing the Zincs religiously. I have the service manual but is there a place that outlines where they are on the aftercooler? Im having a bit of trouble finding a resource for that?

Beyond that, i've heard staying ontop of the aftercoolers themselves is a big service item, Should I have them pulled, inspected and pressure tested? What happens if there is an issue? where do you get replacements?

Any other tips you would care to share?

Many thanks.

-Nate in Vancouver
Click to expand...

the major service interval is 250 and 2000 hours and includes the valve adjustment and injector synchronization. Is there record of that being performed by the previous owner? If not, you’ll want that performed by a Caterpillar mechanic as it requires special tools and knowledge

the aftercoolers should be periodically removed, cleaned by a good radiator shop, pressure tested for leaks, and reinstalled with a fresh coat of paint. Ours was also a lake boat and had never been done where we also had about 1000 hours so I did it as a baseline. This can be a DIY job if you’re ok unbolting and wrestling them out. Replace the turbo to aftercooler hose and clamps while they’re off

most of us also replace all the soft hoses and clamps throughout the engine if they haven’t been done recently.

The CAT ELC (coolant) has a 5 year life so that might also be due, if there’s no record of it I would do it as a baseline.

the walker airsep filter should be cleaned annually and then re-oiled. Walker makes a kit or any K&n filter recharge kit will do.

There are a total of 11 zincs per engine (5 aftercooler, 2 gear cooler, 3 heat exchanger, 1 exhaust) so I’d inspect and probably replace all of them.

oil changes as you said, and both primary (racor) and secondary fuel filters periodically. I do ours annually but I think. The manual calls for 250 hours.

seawater impellers if they’ve not been done in the last year or two. These engines like to eat them.

not specifically on the engine but you may also want to do a transmission oil change including cleaning or replacing the filter element.
 
maintenance is key

the problem with any 26 year old boat is establishing the BASELINE.

Typically when an owner is considering selling or when a boat is put up for sale the maintenance schedule is, for the most part - IGNORED.

On top of that, many owners do not have the depth of knowledge to properly maintain this equipment and other than oil/filter changes, do not keep good records.

These 3116/3126 CATS will run forever IF PROPERLY MAINTAINED.

So, in the event there is a lack of accurate logged service/repair data as a new owner of an old boat you have to do some investigation into WHAT was done and WHEN it was done.

If you can build a solid BASELINE of the needed services and repairs, these engines will serve you well.

Otherwise, instead of being PROACTIVE with these things, you will become REACTIVE which in the long run will result in a less than reliable vessel, cost more money and ultimately sour an owner to the boat.

Lots of great info here on CSR.

Educate yourself, and be ahead of the curve.

BEST !

RWS
 
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