Official Caterpillar3116/3126 Thread

Strecker25 said:
to Mitch’s point, mine get now where near operating temp idling. If I throttle them up I might be able to push to 160 but they won’t go much past 120-130 idling with no load

out boats underwater exhaust is pretty far outboard of the centerline and the pickups are just about on the keel but all boats are different.

Could be chasing a ghost but id start to think about restrictions and somehow verify you’re getting proper raw water flow
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I wanted to clarify, I was in neutral at 1900+ rpms at the dock when it went up. It doesn't overheat at -1600rpms under load or in neutral.

I just switched out the impeller today. The old one from the previous owner appeared to be larger vanes than the new one from Caterpillar. That being said, it still got to 190 running at 1900+ rpms in neutral. And the water flow on the starboard side is still noticably less than on the port at the same 750ish rpms.

My diver is going to check and see if the ball valve on the seacock is off kilter this coming week. However I opened both strainers and opened the seacocks and appeared to get comparable gushes.

Coolant side flushed
HEX cleaned and free of debris
New impeller from Cat
Fresh coolant, CAT ELC
New 190 degree thermostat from Cat
Checked and tightened Hose Clamps

Any other ideas??
 
Thomas Griffith said:
I wanted to clarify, I was in neutral at 1900+ rpms at the dock when it went up. It doesn't overheat at -1600rpms under load or in neutral.

I just switched out the impeller today. The old one from the previous owner appeared to be larger vanes than the new one from Caterpillar. That being said, it still got to 190 running at 1900+ rpms in neutral. And the water flow on the starboard side is still noticably less than on the port at the same 750ish rpms.

My diver is going to check and see if the ball valve on the seacock is off kilter this coming week. However I opened both strainers and opened the seacocks and appeared to get comparable gushes.

Coolant side flushed
HEX cleaned and free of debris
New impeller from Cat
Fresh coolant, CAT ELC
New 190 degree thermostat from Cat
Checked and tightened Hose Clamps

Any other ideas??
Click to expand...


================================

I feel bad that as a newbie 3126/Dancer owner I've been dominating the thread with questions and have contributed little.

Let's now reverse that trend.

One engine OK and one running hot.

Detective work time.

Get a decent IR thermometer, they're not expensive.

Begin shooting the temps following the raw water circulation trail and the coolant trail.

Record those temperatures on a pad and do a comparison.

The location of the increased temp will tell you what you need to know.

Maybe you'll luck out and it'll be the temp sending unit........

BEST !

RWS
 
ttmott said:
don't you check the coolant as a part of the maintenance? Red, Green, Blue it still needs to be checked.
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I send my coolant to Blackstone with my oil samples to get analyzed.
The coolant Cost a little more than the oil sample but it tells the me the condition of the coolant.
 
Maybe A Dancer said:
================================

I feel bad that as a newbie 3126/Dancer owner I've been dominating the thread with questions and have contributed little.

Let's now reverse that trend.

One engine OK and one running hot.

Detective work time.

Get a decent IR thermometer, they're not expensive.

Begin shooting the temps following the raw water circulation trail and the coolant trail.

Record those temperatures on a pad and do a comparison.

The location of the increased temp will tell you what you need to know.

Maybe you'll luck out and it'll be the temp sending unit........

BEST !

RWS
Click to expand...

Funny you say that, my IR thermometer happened to die. However, in doing some further inspections i noticed that the paint on the Aftercooler was effectively burnt off (i recognized the difference from when i overheated my Traeger pellet grill and the paint melted away) in about a quarter section closest to the air intake on the starboard side. I'm not so sure what would cause that, and haven't quite figured out how to take apart the aftercooler. Wondering if there is a more direct fix, such as flushing just the aftercooler. My new IR Thermometer is on its way.

I am new to diesels altogether so i do not contribute much just yet myself! Wondering what could cause low flow and cause the aftercooler to heat up in a specific area? These engines were basically dock queens until we bought the boat so chasing a lot of ghosts.
 
Maybe A Dancer said:
================================

I feel bad that as a newbie 3126/Dancer owner I've been dominating the thread with questions and have contributed little.

Let's now reverse that trend.

One engine OK and one running hot.

Detective work time.

Get a decent IR thermometer, they're not expensive.

Begin shooting the temps following the raw water circulation trail and the coolant trail.

Record those temperatures on a pad and do a comparison.

The location of the increased temp will tell you what you need to know.

Maybe you'll luck out and it'll be the temp sending unit........

BEST !

RWS
Click to expand...
Pull the gear cooler (pull both of them) and get them cleaned and pressure tested. I'd say on these engines that these coolers are a prime culprit for squeezing down raw water coolant flow. You should do these coolers as part of baselining your boat anyway.
 
I didn’t see that you checked the gear coolers or tanked the aftercooler
 
ttmott said:
Pull the gear cooler (pull both of them) and get them cleaned and pressure tested. I'd say on these engines that these coolers are a prime culprit for squeezing down raw water coolant flow. You should do these coolers as part of baselining your boat anyway.
Click to expand...

=====================

I've heard tell of disasters on the gear coolers.

My dock queen has spent 25 years in salt water.

Cheap insurance to just replace the gear cooler.

When I'm done catching up the deferred maintenance, she'll get a fresh water flush after use, with s 30 second or so shot of SALT_AWAY to pickle her raw water system until the next start-up.

Been doing this successfully with my mostly aluminum Yanmar 6 LP since 2006 - never had to service any of the coolers, and none have failed to date.

Cheap, easy PM

BEST !

RWS
 
Maybe A Dancer said:
=====================

I've heard tell of disasters on the gear coolers.

My dock queen has spent 25 years in salt water.

Cheap insurance to just replace the gear cooler.

When I'm done catching up the deferred maintenance, she'll get a fresh water flush after use, with s 30 second or so shot of SALT_AWAY to pickle her raw water system until the next start-up.

Been doing this successfully with my mostly aluminum Yanmar 6 LP since 2006 - never had to service any of the coolers, and none have failed to date.

Cheap, easy PM

BEST !

RWS
Click to expand...
Well, you are in error on the Cat coolers. They are very robust and should last many years. Pull them, have them cleaned and pressure checked. They are the primary choke point due to zinc pieces and calcium buildup on raw water flow. It seems, however, you have a lot of experience here so I'll stand down.
 
ttmott said:
Well, you are in error on the Cat coolers. They are very robust and should last many years. Pull them, have them cleaned and pressure checked. They are the primary choke point due to zinc pieces and calcium buildup on raw water flow. It seems, however, you have a lot of experience here so I'll stand down.
Click to expand...

====

Good background in YANMAR 6LP Marine and MACK 6 cylinder Maxidyne tip turbine intercoolers & Econodyne fwd mounted intercoolers all running triple countershaft gears and 44,000 rear ends under double frames.

Zero experience with CAT Marine, and I have a GREAT FEAR of future cooler failure due to the P.O.'s inattention to servicing these items. His failure to change engine coolant caused a turbo failure and likely a head gasket (to be determined) on the Kohler genny.

I am humbly seeking knowledge of those who know more than I and the sharing of opinions.

BEST !

RWS
 
ttmott said:
Pull the gear cooler (pull both of them) and get them cleaned and pressure tested. I'd say on these engines that these coolers are a prime culprit for squeezing down raw water coolant flow. You should do these coolers as part of baselining your boat anyway.
Click to expand...

Gear cooler: is aftercooler?
 
Thomas Griffith said:
Gear cooler: is aftercooler?
Click to expand...
Gear cooler is to cool the gear oil. These are the "choke" point in the raw water flow.
Aftercooler is for cooling the aircharge from the turbochargers. Cat 3116 aftercoolers are jacketed with the engine's coolant; Cat 3126 are jacketed with raw water.
 
ttmott said:
Gear cooler is to cool the gear oil. These are the "choke" point in the raw water flow.
Aftercooler is for cooling the aircharge from the turbochargers. Cat 3116 aftercoolers are jacketed with the engine's coolant; Cat 3126 are jacketed with raw water.
Click to expand...

Hm, any chance you can direct me to where they're located on the engine?
 
Thomas Griffith said:
Hm, any chance you can direct me to where they're located on the engine?
Click to expand...
Sure - the gear coolers are under the electrical J-box on the back of the engine just above the flywheel housing. They are about 5 inches in diameter and about 14 inches long. If I remember the hose size going in and out is 2 inch.
So, from the through hull and strainer the hose connects to the fuel cooler which is just behind and below the raw water pump on the engine. The fuel cooler connects to the raw water suction side with a short section of hose. The raw water pump discharge then routes to one or two locations depending upon engine- one the engine Hx end cap (rubber formed hose) and for the 3126 a 1 inch hose around the back of the engine to supply cool raw water to the aftercooler. Back on the engine Hx, the end caps split the Hx into two halves, a supply and return (it's a loop). Then on the other side of the Hx end cap where the raw water pump discharge hose is connected is the Hx discharge connection that routes the water to the gear cooler; that is a coupling hose, hard pipe, and coupling hose to the gear cooler. The raw water goes through the gear cooler and exits to a hose that routes the raw water into the exhaust mixer.
 
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Here is a graphic I threw together using an image off the internet
Cat Cooling.jpg
 
Maybe A Dancer said:
====

Good background in YANMAR 6LP Marine and MACK 6 cylinder Maxidyne tip turbine intercoolers & Econodyne fwd mounted intercoolers all running triple countershaft gears and 44,000 rear ends under double frames.

Zero experience with CAT Marine, and I have a GREAT FEAR of future cooler failure due to the P.O.'s inattention to servicing these items. His failure to change engine coolant caused a turbo failure and likely a head gasket (to be determined) on the Kohler genny.

I am humbly seeking knowledge of those who know more than I and the sharing of opinions.

BEST !

RWS
Click to expand...
Before I forget - if the coolant jacket is as corroded as it appears you should probably pull and replace the engine oil cooler. It is mounted in the side of the engine block and in the engine's water jacket.
 
$7K-10K +/- ???
  • Belts and hoses look original, suggested replacement
  • Starboard engine fuel primer pump leaking fuel
  • Starboard engine expansion tank is bent and damaged
  • Starboard synchronizer drive is broken
  • Aftercoolers severely overdue on service
  • Exhaust bypass hoses need replacing along with generator siphon hoses
  • Props need to be tuned to allow for full RPMs
 
Is everything that needs to be cooled (what is that list?) on the 3126 raw water versus coolant cooled? With the exception of the block of course.
 
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