CAT 3126s overheating/running hot after sucking up mud

ttmott said:
What Mr. Webster is saying for a baselining process is precisely what you should do.
What I'm saying is as your boat got through sea trials without an overheating issue then subsequently you got into a situation that filled the raw water passages with silt and mud you should inspect and flush everything, including the exhaust diffuser (shower heat). This is why I'm recommending as the easiest path to get back on the water to flush the diffuser.
The process is:
  • Remove the exhaust hose from the diffuser/riser.
  • Install suitable protection to prevent water from entering the exhaust path and consequently getting to the turbocharger turbine. I would pack a towel in there tightly.
  • Remove the hose between the raw water inlet fitting on the bottom of the riser.
  • With a hose and spray nozzle spray water at high velocity into the diffuser ports allowing any debris to exit from that low port the hose was connected.
Here is your checklist to verify the raw water flow is unobstructed -
  1. Verify intake grating and ports under the boat are clean and open
  2. Verify the through hull valve through the strainer, fuel cooler, and hoses to the raw water pump are clean of any obstructions.
  3. Verify the raw water pump is in correct working order and free of air leak (new impeller, gasket, and key as a minimum).
  4. Verify / clean engine heat exchanger. All tubes should readily flow fresh water.
  5. Verify the hoses and piping between heat exchanger and gear cooler are clean and unobstructed.
  6. Verify the gear cooler is clean and free of any plugged tubes. BTW when an engine is showing signs of higher operating temperature the gear cooler is the first place to look as it doesn't take much to inhibit it's flow.
  7. Verify the hose between the gear cooler and exhaust riser is free flowing and clear.
  8. Inspect and clean the exhaust riser water passages and diffuser (shower heat)
None of these steps are difficult or time consuming.
Click to expand...

Perfect, thank you.

Slightly off topic, I did buy a endoscope camera to see how much value it will add "looking up and into a hose" before taking something apart. That is not my plan, it's more out of curiosity and for futures uses as well. I also thought this could come in handy during a trip/on the water before one starts to tear things apart. Take a quick look/see with the camera first.

https://www.amazon.com/dp/B01MYTHWK4?psc=1&ref=ppx_yo2ov_dt_b_product_details
 
Sea trial, port engine stays at 190 on plane, starboard engine stays just under 200. Confirmed with gauges on top of engines and temp laser gun.

Today I hauled the boat, back flushed and flushed the grates and replaced the cover plate on the port raw water pump. Here's the back of the previous plate on the port engine, doesn't look too bad to me but went ahead and replaced it. This is the first time any of the engines ran less than 200°, in this case port engine 190. Port engine is the one I barnacle bustered closed loop a couple weekends ago but did not see trial afterwards.

I also noticed the port engine oil pressure was a little higher, usually runs around 50 on plane, it stayed around 60.

Engine compartment is way too hot to do anything else today unfortunately.

16609448550863021850633428852217.jpg
 
Last edited:
mrsrobinson said:
Sea trial, port engine stays at 190 on plane, starboard engine stays just under 200. Confirmed with gauges on top of engines and temp laser gun.

Today I hauled the boat, back flushed and flushed the grates and replaced the cover plate on the port raw water pump. Here's the back of the previous plate on the port engine, doesn't look too bad to me but went ahead and replaced it. This is the first time any of the engines ran less than 200°, in this case port engine 190. Port engine is the one I barnacle bustered closed loop a couple weekends ago but did not see trial afterwards.

I also noticed the port engine oil pressure was a little higher, usually runs around 50 on plane, it stayed around 60.

Engine compartment is way too hot to do anything else today unfortunately.
Click to expand...

Sounds like with a little bit of luck and some more BB for the starboard side you might be on the water !!
 
Progress. I sort of expected a lightswitch type fix where it all just returns to normal but maybe you're slowly taking care of small issues that were there and somehow exacerbated by the mud

nothing wrong with 190 if they stay there, although I would try and verify by cross-checking the engine gauges or hitting it with an IR gun
 
Yep, I did use an IR gun, temperatures confirmed. Bought some headphones to jump into the engine compartment on plane and put the boat on autopilot.

Got scared for a second when I came back to the helm and tried to steer and had none, forgot I was still an autopilot.

IR gun on exhaust hoses and riser was around 95°, is that normal?
 
mrsrobinson said:
Yep, I did use an IR gun, temperatures confirmed. Bought some headphones to jump into the engine compartment on plane and put the boat on autopilot.
Click to expand...
YIKES. Please be careful doing that (i.e. don't), if you somehow get incapacitated in the ER for some reason, it will not end well. I'm glad to hear that you may be on the tail end of your sorrows with the overheating, but don't get to the finish line with it and destroy your boat (and yourself) in an accident!

This comes to mind, he thought it would be harmless to hit the head while underway solo.
 
mrsrobinson said:
Yep, I did use an IR gun, temperatures confirmed. Bought some headphones to jump into the engine compartment on plane and put the boat on autopilot.

Got scared for a second when I came back to the helm and tried to steer and had none, forgot I was still an autopilot.

IR gun on exhaust hoses and riser was around 95°, is that normal?
Click to expand...
The exhaust will be hotter on top than on bottom but that temp on top is of no concern.
The test is temperature creep under cruise load. If it is stable between 190 and 200 you are good to go.
Looking much better; looking like you got this one licked and can enjoy the rest of the summer.
 
GnrlPatton said:
YIKES. Please be careful doing that (i.e. don't), if you somehow get incapacitated in the ER for some reason, it will not end well. I'm glad to hear that you may be on the tail end of your sorrows with the overheating, but don't get to the finish line with it and destroy your boat (and yourself) in an accident!

This comes to mind, he thought it would be harmless to hit the head while underway solo.
Click to expand...

youre a brave soul lol. I hesitate to leave my seat to get a beer (from the cockpit fridge)
 
Well I've never done that before, and I moved very fast, but great points, didn't even think about that. I was more worried about hitting something in the water that I didn't see before jumping into the engine compartment.
 
mrsrobinson said:
Well I've never done that before, and I moved very fast, but great points, didn't even think about that. I was more worried about hitting something in the water that I didn't see before jumping into the engine compartment.
Click to expand...

Those laser therms have a decent range I bet you could get readings from the helm under way
 
I was taking temperature readings off of the metal block in the red circle, what is that? I assumed it was the regulator housing.

Screenshot_20220819-205355.png
 
mrsrobinson said:
I was taking temperature readings off of the metal block in the red circle, what is that? I assumed it was the regulator housing.

View attachment 132475
Click to expand...

thermostat housing and block area, so that’s a good place.

it would be interesting to measure return coolant temp as it gets past the block and back to the beginning but I’m not sure what that spec is. I’d think the coolant temp mostly stabilizes throughout the system
 
were those sea trial temps prior to the short haul, or after?
 
You must log in or register to reply here.

Forum statistics

Threads
113,202
Messages
1,428,453
Members
61,108
Latest member
asigman
Back
Top