CAT 3126s overheating/running hot after sucking up mud

[Riptide III]

Based on my limited experience, that heat exchanger alone would cause my engine to overheat. That is at least 50% clogged (remember, the bottom half is where all the water enters the top half is return/exit). It is my understanding that you corrected that and it’s still overheating?

 

[Carver370]

I had less of a clogged heat exchanger than that and would notice the temps climbing on my port engine. Dug out all of those old impeller pieces that someone was too lazy to find and I was back in business.

The impeller looks normal for an old one, it has formed a set which would make me replace it with a new one.

 

[douglee25]

The problem I see is, you never took off the cap on the other side. You aren't able to fully assess what's going on until you can look from one side to the other.

 

[ocgrant]

You really need to pull all the coolers out of the boat, have them professionally cleaned and tested and then reinstall. That way you have a true baseline to start from. Any simply flushing still in the boat is probably not going to get the packed in mud or debris out like a tear down will.

 

[mrsrobinson]

Whatever is at the 4 - 5 o-clock area. That looks dirty to me. Did you go to the other end of the tube bundle and take the cap off?

Tried to, couldn't get the last bolt off, couldn't get a wrench, socket, tool on it

 

[mrsrobinson]

In pics #2 and 3 looks like dings on the inside edge of the pump, maybe from prying. Can't tell from pics if they contribute to your problem but they shouldn't be there.

Thanks, I didn't pry at all, I used the bolt to extract it

 

[mrsrobinson]

Doesn't appear anything wrong with the photos except for that pump housing.
The O-Ring doesn't look healthy and clean. If there is even the slightest air leak on that pump cover it will malfunction and not pump enough water to cool at the higher RPM's.
Spic n' Span that thing; new O-ring with silicone grease or better yet Alco Metalube on it.

I replaced the o-ring with the new impeller

 

[mrsrobinson]

The problem I see is, you never took off the cap on the other side. You aren't able to fully assess what's going on until you can look from one side to the other.

Agreed

 

[mrsrobinson]

You really need to pull all the coolers out of the boat, have them professionally cleaned and tested and then reinstall. That way you have a true baseline to start from. Any simply flushing still in the boat is probably not going to get the packed in mud or debris out like a tear down will.

Agreed, haven't had any luck finding a radiator shop who will do the work though

 

[mrsrobinson]

Sounds like I've got some more work to do with the heat exchangers, I'll tackle them again hopefully next weekend. I'll see if I can get them cleaned out myself with both end caps off, using the 22 caliber rod I bought, with them still mounted on the boat. My goal is to get the boat running again to salvage this season. If that doesn't work I'll take them off and try to find a radiator shop that will clean and test them. If not I'll soak them in descaler myself and do the cleaning. Bigger job, holding off on doing that one if I can.

Someone correct me if they disagree with this plan.

 

[dtfeld]

The only way I was able to get the heat exchangers out was to remove the coolant tank. But I remeber not being able to get a wrench on at least one nut...

 

[fwebster]

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.'

Heat exchangers and their solder joints can easily be damaged with brass or steel rods. I don't know what 22 caliber rods is that you mentioned, but you should olny "rod" heat exchanger tubes with a wooden bowl or and aluminum rod of the appropriate size.

 

[mrsrobinson]

The only way I was able to get the heat exchangers out was to remove the coolant tank. But I remeber not being able to get a wrench on at least one nut...

Yeah I can't remember which bolt it was on the port side of the port engine, I want to say one on the bottom, but I couldn't find a way to get a wrench on it without disassembly of other stuff.

 

[mrsrobinson]

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.'

Heat exchangers and their solder joints can easily be damaged with brass or steel rods. I don't know what 22 caliber rods is that you mentioned, but you should olny "rod" heat exchanger tubes with a wooden bowl or and aluminum rod of the appropriate size.

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

 

[carterchapman]

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

A long wooden grill skewer works great. They are pointed at one end.

Your CAT dealer should be able to hot tank your HE for you or recommend who they use...

 

[Maybe A Dancer]

not to beat the horse post mortem, but wouldn't it be easier/simpler/less work and time invested (and Greg, you've got a LOAD of time invested in this problem already - how many weekends????) to simply remove the entire unit and take it to your CAT dealer?

Not only will the HEX be cleaned thoroughly and correctly, it will be assembled correctly and tested as well.

There's got to be a CAT dealer SOMEWHERE that can handle this for you.

Just sharing my own experience.

BEST !

RWS

 

[ttmott]

And what about that exhaust shower head? Has it been looked at and flushed out?

 

[mrsrobinson]

Local CAT dealer was clueless when I asked them about this so they can't do it. Every radiator shop I've called and Marina service shop in the area is clueless. The Marina service shops said they would soak it overnight in simple green or soap. The Caterpillar dealership has no idea what I'm talking about. Their focus is on heavy equipment and land equipment. I guess I could start looking outside my area and the area where the boats slipped, I was trying to not have to do that though and drive all over the state.

No to the exhaust shower head, haven't looked at that yet. All I'm trying to do at this point is pick one thing in priority order that I can do next as I have limited time on the boat the next few weekends. If you think that's what I should do next I will

 

[ttmott]

I have seen Hx's a lot worse than yours and they cooled just fine. Mine one time looked to be 30% plugged with grass and it was fine until I needed to remove the end cap to retrieve impeller blades when I found the grass. Keep in mind that as far as the end cap on the other side of the one with hoses that first things have to pass through the tubes then become lodged on the return tubes on the other side - not practical to say that is the source of your problem. Plus if you remove that end cap you will be required to drain the engine coolant. There is a lot of excess capacity in these coolers.
At this point as far as the raw water system I'd recommend, again -
Inspect the through-hull grate and inside that grate.
Inspect the shower-head and flush it out.
Verify the raw water pump has no air leaks; If you cleaned that thing up, installed a new O-Ring, and verified the cover plate is flat and seals well you are probably good there.
Do a water flow test.
If all of this is good then your raw water system is probably acceptable; then on to the engine coolant side of things.

But, I say that it is essential for all buyers of used boats to get their boat baselined by refurbishing all things needing periodic service and anything noted as broken or defective.

 

[mrsrobinson]

Thanks Tom, baselining was the plan, until the mud event, I'm just trying to salvage what's left of the season at this point. I had tickets to go see the Padres play the Nationals last night, we were going to boat to a marina within walking distance of the stadium, had to sell them.