CAT 3126s overheating/running hot after sucking up mud

mrsrobinson said:
Thanks Frank, yeah I'm not really excited about putting a rod in there to clean the tubes and would prefer dock water pressure with the hose, so I'll try this if I can get the tube out on the port engine. Quick question, with the port engine inside hex cap off is there any magic to pulling the tube out? Looking at the picture above, which is the port engine inside cap, what should I be pulling on to slide it out?

Here's the rod I purchased, some folks on here recommended this approach for cleaning the tubes

Hoppe's No. 9 Gun Cleaning Aluminum Rod, Universal Rifle https://a.co/d/6RN8jku
Click to expand...

Greg,

The heat exchanger tubes are all mounted in a bundle. I would not try to rod the tubes in place because anything you push out is just going to end up further in the cooling system. The tube bundle is mounted in the end caps on either end with o-ring seals. Therefore, don't mess with it until you get a new set of orings from Caterpillar. With care in removing the tubes the o-rings can be reused, but thet are easy to cut if you aren't able to feel the assembly as you insert the cleaned tube bundle.

This is off the subject, but it seems to me you need to address your marina situation almost first…..

1. you cannot use a trained certified technician in the marina.
2. other diesel servicing options don't appear to exist if the local service options don't even know what a heat exchanger is.

Personally, I wouldn't tolerate your situation. I think it is a restraint of trade if your marina management prohibits services on the property that the marina doesn't supply. At the worst, the service provider may have to show evidence of liability coverage, but anybody that works on expensive diesel engines will carry liability coverage anyway.

Good luck with it……….
 
fwebster said:
At the worst, the service provider may have to show evidence of liability coverage, but anybody that works on expensive diesel engines will carry liability coverage anyway.
Click to expand...

This is all my marina requires is proof of liability coverage. (and my owner is very strict)
 
fwebster said:
Greg,

The heat exchanger tubes are all mounted in a bundle. I would not try to rod the tubes in place because anything you push out is just going to end up further in the cooling system. The tube bundle is mounted in the end caps on either end with o-ring seals. Therefore, don't mess with it until you get a new set of orings from Caterpillar. With care in removing the tubes the o-rings can be reused, but thet are easy to cut if you aren't able to feel the assembly as you insert the cleaned tube bundle.

This is off the subject, but it seems to me you need to address your marina situation almost first…..

1. you cannot use a trained certified technician in the marina.
2. other diesel servicing options don't appear to exist if the local service options don't even know what a heat exchanger is.

Personally, I wouldn't tolerate your situation. I think it is a restraint of trade if your marina management prohibits services on the property that the marina doesn't supply. At the worst, the service provider may have to show evidence of liability coverage, but anybody that works on expensive diesel engines will carry liability coverage anyway.

Good luck with it……….
Click to expand...
Agreed and thanks, I've tried to address this with Marina but they've said no refunds. So I will need to make a decision if I need to eat about $6,000 in remaining slip fees.

I have the o-rings you mentioned, sounds like once I pop them off with my dental pic the bundle slides out, right?
 
16604985298493066431956853122210.jpg
Reading a lot of these texts I went ahead and bought new plates for the back of the raw water pumps. I remember seeing some scoring on the inside but didn't know how much was acceptable. They are not painted. I we'll paint outside, should I paint the inside? My thought is no.

The new ones have arrows with them that say cam and inlet. Should that side go on the inside or outside come up I'm thinking outside.
 
mrsrobinson said:
Agreed and thanks, I've tried to address this with Marina but they've said no refunds. So I will need to make a decision if I need to eat about $6,000 in remaining slip fees.

I have the o-rings you mentioned, sounds like once I pop them off with my dental pic the bundle slides out, right?
Click to expand...
Pull both end caps off before pulling the bundle out. Push on the other side of the bundle to unseat it; don't pry on that thin flange, it should just pop loose and easily slide out. The end cap without the hoses slides over and seals to the bundle end ring. When re-assembling install the Hx housing O-ring that the bundle flange seats to using plenty of Acro Metalube then slide the bundle in. Then install the end cap with a new O-Ring onto that flange. The end of the tube bundle will remain centered in the other end as it is a rather tight tolerance. Then Install the O-Rings (there are two of them) into the other end cap again using Metalube and finally slide that end cap over the bundle and seal it to the Hx housing.
 
mrsrobinson said:
Agreed and thanks, I've tried to address this with Marina but they've said no refunds. So I will need to make a decision if I need to eat about $6,000 in remaining slip fees.

I have the o-rings you mentioned, sounds like once I pop them off with my dental pic the bundle slides out, right?
Click to expand...

I have run into this a few times. My thoughts are, if a marina does not offer or cannot perform a service, they should let a credentialed company in to perform said service.

I still think I’d call a few surveyors, marinas, or brokers and ask if they have a Cat mechanic. Go get a transient slip there even if you have to idle the entire way there and let them have at it. Bonus, you get a vacation at another marina for a week or so.
 
@ttmott I feel like I'm getting conflicting information on whether or not to pull off the other end cap to pull the bundle out. What I'm reading here is if I have to pull that end cap off I'll lose all the coolant it will need to replace that as well.

I'm not doubting or second-guessing anyone, just looking for the least path of resistance to get the bundle removed and flushed at the dock. I'm fine draining the coolant and replacing it at the same time as well since that's on my short list to do.
 
mrsrobinson said:
@ttmott I feel like I'm getting conflicting information on whether or not to pull off the other end cap to pull the bundle out. What I'm reading here is if I have to pull that end cap off I'll lose all the coolant it will need to replace that as well.

I'm not doubting or second-guessing anyone, just looking for the least path of resistance to get the bundle removed and flushed at the dock. I'm fine draining the coolant and replacing it at the same time as well since that's on my short list to do.
Click to expand...
Well, you lose the coolant regardless; it's the tube bundle that exchanges heat between the raw water and engine coolant. One side of the tube bundle is engine coolant and the other raw water. That end cap simply provides seals to separate engine coolant from raw water at that end.
Going back to the crux of your problem which is silt and mud right? If you flow dock water as fast as it will spray into each the tubes and you see clear water coming out other tubes I think from the raw water side of things that the Hx isn't your problem. If, on the other hand, you can't get water to flow through a lot of the tubes then that is another story. I think your problem resides elsewhere.
 
A diver can take a look at the potentially debris clogged raw water intakes . . .

RWS
 
I have all day Saturday to work on this, woo hoo!

For clarity, in priority order (I quoted some of your comments) to try salvage some of the season, knowing I need baselines soon as well. Otherwise I will be all over the place on Saturday.

"Inspect the through-hull grate and inside that grate" unfortunately will not happen with a short haul or diver by Saturday. I need to check to see if the marina allows divers, or even if divers are available.

On one engine:

  1. Check raw water flow on the outtake side of the raw water pump. One goes to the after cooler, one goes to the HEX. Should I blocked one off to test the other, or test both at the same time? I think the latter.
  2. I think I am hearing check flow at others points as well, after coolers?
  3. I should have a 1 foot 2" section of clear hose left on the boat by the service shop by then so I may plug that in as well to watch the flow.
  4. I am hearing a "verify/check for air leaks" theme. I am not sure how to do this other than what the service shop told me to do with clear hose.
  5. If flow looks good remove the HEX bundle: Quoting Frank I may only have to take on end cap off: "You should be able to remove the tube buddle by removing the inboard end cap on the port engine (outboard one on the STBD side). They easily slide out , if there is room to clear any obstructions that Sea Ray put in the way. I hope there is enough room on a 380DA. I did this several times on my 450DA over my 25 years of ownership by just removing the Stbd Racor bracket and filter assy. and laying it in the floor of the bilge….... 2 bolts and nuts.
    Once the tube bundles are removed you should be able to reach the length of the heat exchanger with the spray from a water hose and the tube bundles can be taken off the boat and cleaned out in a bucket on the dock.    '"
  6. Test by taking boat out on plane
  7. If success, do the other engine
  8. If not success inspect the shower-head and flush it out
  9. Replace raw water pump backing plate - still not sure which side is the inside and which is the outside (see pic above) - can someone confirm?
  10. Do step 3 again
  11. If all of this is good then the raw water system is probably acceptable; then on to the engine coolant side of things.
 
If it was me, I'd make arrangements for a diver - HE'S YOUR COUSIN - to check the inlet grates first.

Seems its one of your few unturned stones. . . . .

Or try it yourself with an underwater flashlight and a decent mask

I keep these on board in the event I run over a line or catch a crab trap and have to cut it off the shaft/prop - actually did happen twice, once when I backed over my dink line....... we use floating lines now, but I digress.....

RWS
 
Maybe A Dancer said:
If it was me, I'd make arrangements for a diver - HE'S YOUR COUSIN - to check the inlet grates first.

Seems its one of your few unturned stones. . . . .

Or try it yourself with an underwater flashlight and a decent mask

I keep these on board in the event I run over a line or catch a crab trap and have to cut it off the shaft/prop - actually did happen twice, once when I backed over my dink line....... we use floating lines now, but I digress.....

RWS
Click to expand...
I have as little as 4' of water under the boat at the dock, I love my boat, but I am not swimming under there with that amount of water ;-)

I've just contacted the marina to see if they can do a short haul for me this week. Or if they allow divers and can recommend one.
 
mrsrobinson said:
I have all day Saturday to work on this, woo hoo!

For clarity, in priority order (I quoted some of your comments) to try salvage some of the season, knowing I need baselines soon as well. Otherwise I will be all over the place on Saturday.

"Inspect the through-hull grate and inside that grate" unfortunately will not happen with a short haul or diver by Saturday. I need to check to see if the marina allows divers, or even if divers are available.

On one engine:

  1. Check raw water flow on the outtake side of the raw water pump. One goes to the after cooler, one goes to the HEX. Should I blocked one off to test the other, or test both at the same time? I think the latter.
  2. I think I am hearing check flow at others points as well, after coolers?
  3. I should have a 1 foot 2" section of clear hose left on the boat by the service shop by then so I may plug that in as well to watch the flow.
  4. I am hearing a "verify/check for air leaks" theme. I am not sure how to do this other than what the service shop told me to do with clear hose.
  5. If flow looks good remove the HEX bundle: Quoting Frank I may only have to take on end cap off: "You should be able to remove the tube buddle by removing the inboard end cap on the port engine (outboard one on the STBD side). They easily slide out , if there is room to clear any obstructions that Sea Ray put in the way. I hope there is enough room on a 380DA. I did this several times on my 450DA over my 25 years of ownership by just removing the Stbd Racor bracket and filter assy. and laying it in the floor of the bilge….... 2 bolts and nuts.
    Once the tube bundles are removed you should be able to reach the length of the heat exchanger with the spray from a water hose and the tube bundles can be taken off the boat and cleaned out in a bucket on the dock.    '"
  6. Test by taking boat out on plane
  7. If success, do the other engine
  8. If not success inspect the shower-head and flush it out
  9. Replace raw water pump backing plate - still not sure which side is the inside and which is the outside (see pic above) - can someone confirm?
  10. Do step 3 again
  11. If all of this is good then the raw water system is probably acceptable; then on to the engine coolant side of things.
Click to expand...

checking flow at various points makes sense but I would probably start with the end which is right before it dumps (or pushes up, rather) into the riser. If the flow is low there then you can start working your way back to find the restriction. I also like the clear hose idea which would show air bubbles
 
mrsrobinson said:
I have all day Saturday to work on this, woo hoo!

For clarity, in priority order (I quoted some of your comments) to try salvage some of the season, knowing I need baselines soon as well. Otherwise I will be all over the place on Saturday.

"Inspect the through-hull grate and inside that grate" unfortunately will not happen with a short haul or diver by Saturday. I need to check to see if the marina allows divers, or even if divers are available.

On one engine:

  1. Check raw water flow on the outtake side of the raw water pump. One goes to the after cooler, one goes to the HEX. Should I blocked one off to test the other, or test both at the same time? I think the latter.
  2. I think I am hearing check flow at others points as well, after coolers?
  3. I should have a 1 foot 2" section of clear hose left on the boat by the service shop by then so I may plug that in as well to watch the flow.
  4. I am hearing a "verify/check for air leaks" theme. I am not sure how to do this other than what the service shop told me to do with clear hose.
  5. If flow looks good remove the HEX bundle: Quoting Frank I may only have to take on end cap off: "You should be able to remove the tube buddle by removing the inboard end cap on the port engine (outboard one on the STBD side). They easily slide out , if there is room to clear any obstructions that Sea Ray put in the way. I hope there is enough room on a 380DA. I did this several times on my 450DA over my 25 years of ownership by just removing the Stbd Racor bracket and filter assy. and laying it in the floor of the bilge….... 2 bolts and nuts.
    Once the tube bundles are removed you should be able to reach the length of the heat exchanger with the spray from a water hose and the tube bundles can be taken off the boat and cleaned out in a bucket on the dock.    '"
  6. Test by taking boat out on plane
  7. If success, do the other engine
  8. If not success inspect the shower-head and flush it out
  9. Replace raw water pump backing plate - still not sure which side is the inside and which is the outside (see pic above) - can someone confirm?
  10. Do step 3 again
  11. If all of this is good then the raw water system is probably acceptable; then on to the engine coolant side of things.
Click to expand...
Negative on 1 - you are interested in water flow where it dumps into the exhaust.
On 5 - I'm sure Mr. Webster would say to press the bundle out from the back side of it rather than pry on that thin flange. Plus without that other end cap off you don't know if the seal to the tube bundle stayed in place. But.....
Also, if the flow looks good you still don't know if the shower head is the obstruction. Inspect and flush the shower head before sea trials - It's one of the easiest things to get to...

On 9 - the side with the embossed printing is outside.
 
Revised:
  1. Check raw water flow where it dumps into the exhaust
  2. Inspect the shower-head and flush it out
  3. Optional: Inspect water flow before it goes into the HEX/After cooler.
  4. Sea Trial
  5. I am hearing a "verify/check for air leaks" theme. I am not sure how to do this other than what the service shop told me to do with clear hose.
  6. If still overheating remove the HEX bundle: Quoting Frank I may only have to take on end cap off: "You should be able to remove the tube buddle by removing the inboard end cap on the port engine (outboard one on the STBD side). They easily slide out , if there is room to clear any obstructions that Sea Ray put in the way. I hope there is enough room on a 380DA. I did this several times on my 450DA over my 25 years of ownership by just removing the Stbd Racor bracket and filter assy. and laying it in the floor of the bilge….... 2 bolts and nuts.
    Once the tube bundles are removed you should be able to reach the length of the heat exchanger with the spray from a water hose and the tube bundles can be taken off the boat and cleaned out in a bucket on the dock.    '"
  7. Sea Trial
  8. If success, do the other engine
  9. Optional but will do anyway since I have new ones: Replace raw water pump backing plate - embossed print on the outside, paint outside, do not paint inside
  10. Sea Trial
  11. If all of this is good then the raw water system is probably acceptable; then on to the engine coolant side of things if still running hot.

I could use a "how to" for inspecting and cleaning the shower head since this will be new to me. I think it's on the hull/port side of the port engine closet to the V-Drive connection. From the first part of this video I think the thick larger white stern to bow tube, to the left of the green garden hose, going into the shorter exhaust hose is what I want to inspect/clean. Or what can I search on? I have tried:

"CAT 3126 riser"
"CAT 3126 shower head"
"CAT 3126 exhaust riser"

with no luck. I found this: https://greenwatermarine.com/products/caterpillar-exhaust-risers.html

 
Last edited:
Not for nothing, and regardless of any other advice you get here, and there has been some really good advice
If post #33 is your heat exchanger, your engine WILL always run hot until you fix that! Raw water only flow thru the bottom half of the tubes. The top half returns back. These are very robust systems but they will NOT sufficiently cool your engines if 50% of the bottom bundles are blocked cutting off 50% of the flow and slowing it down. I have spent my share of time chasing cooling issues. Fix each problem as you identify it. That IS a problem. Maybe not your only one. But most certainly it is one. Get a 5 gallon bucket and some CLR and soak it yourself. If post 33 is not yours, sorry for the rant.
 
Thank you @Riptide III. Post number 33 is my port heat exchanger. I should have taken another picture after pulling the impeller bits out of it but yeah that's about what it looks like.
 
Okay so you can't tell me to clean and inspect something, the shower heads in this case, without giving me a little help how ;) I've been crawling all over the Internet and can't find anything.

Help a brotha out! ;)
 
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