Muddy CAT 3306

I was doing hull cleaning underwater and as a novice, came to the idea to anchor the boat close to shore. It sounded nice to scrape the barnacles and standing on ground with my gear on. Well, it was a really bad idea. Unfortunately, there was a super low tide yesterday and my boat got grounded on rocks and mud. It was scary, but I’ve got lucky. Once the tide was up again, I moved the boat to deeper area. The plan was to continue scraping today. Unfortunately, the weather picked up and I was in the wide open. I’ve decided to return home and see, if I can continue work.
About 30 minutes after I left, I see that the rpm is going down. It stopped around 1500, but there was a sound, which was new. I stopped and went to the ER. What I could see was the seawater was bubbling out at the water pump section, where it connects to the engine. There is no gasket to see outside, so I was puzzled. My bilge pump was working, so I did not panic. However, I had another hour to go and I did not want to risk it. I have removed the seawater pump. When I did that, a gray muddy mix of water was coming out. The boat was rolling, so the seawater was still bubbling out, even with the engine shut. I could see where the pump’s shaft would go into a housing and there were some O rings and a partial gasket. The rings would not come out, so there was not much I could do. Besides, I was on anchor in the middle of the water. I had no choice, but put everything back and start the engine. When I did that, the grey muddy liquid shot out of the air exhaust, down to the ER floor. It stopped after a minute, but I could see that the filter housing was also full with mud and water mix. The seawater was still bubbling out at the pump, but I was able to pull the anchor and go slowly back home. I was almost at my spot when the overheating alarm came on, so I had to shut the engine. Bad moment. I was close to boats and docks. I started the engine again and i could see the temp went down suddenly I could moor my boat.
At this point, only clear water was bubbling out into the bilge.
I am not familiar with the engine, yet. I do have the manual and parts book, but I think I will need to replace few things, to make it work again.
Can someone explain to me what section of the engine is, where the pump connects with that shaft? Does it has to be replaced, or just removed for cleaning? I am sure the O rings need to be fixed, which will require removal. I just don’t know, how far do I need to disassemble that whole area? The seawater pump seems to be working properly, I just need new gasket for the hose connections.
I don’t mind the work and I know I will need to spend some money, but I am looking for directions.
Any questions are welcome. See photos attached.

I’d say the seals in the sea water pump have given up the ghost.
You’d probably best send the pump out to a shop for a rebuild, then get after draining and flushing the crankcase oil, which has been contaminated with seawater.
Hopefully no further damage was incurred, you won’t know till you get it running again.

Sure sounds like you picked up a load of mud. Also since the temp dropped suddenly it seems the blockage fixed itself. It would be nice if you could jury rig and run fresh water thru the engine raw water side for awhile to really flush it out. I'd run it for a good while monitoring the temp and water flow and see how to does. The pump might have been pushing against the blockage and the water had to go somewhere. If the pump(s) still leak you should be able to get a rebuild kit. Just need to know the pump ID.

Your pump is gear driven and the shaft seal is to keep water out of the gear train. Usually when the pump seal fails water drips from a weep hole on the outside before ruining the seal enough to allow water into the gear train. You sucked up mud, had a blockage and the water pressure built up enough to blow out the seal. The pump has to be rebuilt.

Now you have sea water in your oil. Not only does the oil need to be changed, but probably changed a few times on a short cycle to get all the water and salt out. Don't run the engine with water in the oil because it won't supply proper lubrication.


A new pump is about $1000 from a non Cat pump dealer and about $900 on eBay.

Update.
I might have been wrong about the mud. Again, the bottom was rocky and some weeds, kelp. Also, I could not understand how the mud went through the strainer, hose/pipe turns? I could be wrong.
Maybe there was mud, after all. As Lepke said, something had to blow the gasket.
But.
When I took apart the pump at the event, I could see deformed rings and metal parts.
Yesterday, I was in Ballard to buy some fittings and I was lucky to be able to talk to a local shop, which handles CAT engines. The nice gentleman told me what to do immediately. If there was water in the oil system, the first thing to do is to drain the oil. This requires to warm the engine up. So, he advised me to remove the head cover and clean it as much as possible, before starting the engine. So, that is what we did.
After the dirty oil was pumped out, we filled it up with fresh oil twice, running the engine in between. My buddy also recommended to add a bit of diesel to the mix, so a diluted oil would wash out crevices easier and the pump out less thicker. The oil change pump was really struggling at the first draining. So, all went well, and the engine shows clean oil on the depth stick, right now.
I also took the pump and related parts to the shop this morning. They are still looking for info, since this is an old engine. They will tell me, if the broken pump can be rebuilt, or a new has to be purchased? I might know more tomorrow.
Either way, I will mount the fixed pump back, when it is ready and will go for a short trip. After that, I will do another oil change, #3.
I will continue to monitor the oil from now on and I will do more oil changes, if I see coloring.
All filters are new and will be also replaced.
I have a suspicion that the shop tech was correct when he said that the pump’s failure was overdue, after looking the photos I showed to him. Maybe the pump was dying already and suddenly just blew up. I cannot prove it, but anything is possible. The only sign could be against this theory is that we tried to catch particles from the dirty oil with a magnet, but it did not pickup anything. Plus, I always check the oil level before a trip and the oil color was always black. Never grey, as it was at this failure.
Anyway, we might never know what was the reason of the failure.
So, the fixing is underway now, and I did not see any rusting around the valves and springs. I am hopeful.

The rings you see in the gear train are from the seal. There may be two seals. One for the oil and one for the water. The bearings are probably ball bearings and will have a number embossed. You can search for them online.
The truth about pumps is someone always makes seals and usually bearings. Some manufacturers offer rebuild kits and popular engines have several aftermarket pump kits.
Usually you can buy everything but the housing.

Depco probably has parts and a rebuild kit. Depco Pump Company
And there are others.
On eBay:
https://www.ebay.com/itm/Caterpilla...480568?hash=item3fe1d08bf8:g:ORsAAOSwZLlexVlb
https://www.ebay.com/itm/1700567-Re...608409&hash=item43f1760ee4:g:~1QAAOSwEeFU-cXQ
You need to check the numbers

Lepke said:

Depco probably has parts and a rebuild kit. Depco Pump Company



You need to check the numbers

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This is great info and I really appreciate it!

One of the challenges I have, including with this shop which is trying to get me a pump, is the serial number of my engine. They can never find it. Yesterday, they told me that CAT engines were produced in the past in many ways and sometimes the models/numbers were not very clear to follow.

See the photo of my manual with the numbers on it. Can you make sense of it?

So I gather that oil turned grey, which means it got water in it. And you have done a few oil changes, that is good. But there is still moisture hiding in the engine in various places. Do not let it sit long while you sort out your pump. Run it at least once a week, maybe more.

And when you get the pump fixed and installed, you want to take boat out and run engine hard to get the oil hot enough to cook out the moisture. Take blowby vent off and let it blow into the engine room. Once engine gets hot you will see steam coming out. Want to keep running it hard til the steam quits, then run a bit longer. When done, open up rocker box (coolest place on engine) and see if there is moisture condensed up there.

Ski in NC said:

When done, open up rocker box (coolest place on engine) and see if there is moisture condensed up there.

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Thank you for this, I will follow your recommendations. I will run it as soon the pump is back on place.

What is the rocker box?

Rocker box is just another term for valve cover.

Ski in NC said:

Rocker box is just another term for valve cover.

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Got it.
I did clean that already well, but I'll check it again, after the run.
Thanks.

66D prefix means industrial engine. So it was built for a grader, front loader, etc. The big difference between land engines and marine engines is usually the land engines have smaller injectors for lower hp, because land engines can't cool as well. Usually the block and internal parts are the same.
Besides eBay, if you're looking for used parts: https://www.surplusman.com/
They buy inventory, engines, transmissions, and so on. Some new stuff, lots of used stuff. Tons of parts. All brands.

Update.
I have purchased a new aftermarket sea water pump and installed over last weekend. I took out the boat for a couple hours, and all looked fine.
This weekend, I went up to Lake Washington and back. It was about 12 hours engine running. I could not see any steam coming out of the rocker vent hose. There was still a bit of water dripping out of the filter housing of this vent hose. The temperature of sea water looked normal around 160-170F and the oil pressure was between 35-40. Both acceptable.
As I was securing my buoy lines at my arrival home, the overheat alarm came on again. Turned off the engine and checked the ER. Everything looked fine. Pump and hoses all were secure. I tried to start the engine couple more times later, but it was overheating again. I had no clue why.
Friend of mine suggested that the water temperature regulator might be the problem. I ordered replacement and it should be here next week. Although, it requires coolant draining, I will replace this thermostat first, before I run the engine again.
Man, this never ends... !

Was coolant level normal? Where did you check coolant level? Did you confirm engine was hot with a temp gun? Was sea water flow out the exhaust normal?

Ski in NC said:

Was coolant level normal? Where did you check coolant level? Did you confirm engine was hot with a temp gun? Was sea water flow out the exhaust normal?

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Yes, sea water was coming out as normal. I also checked the strainer.

I checked the coolant level at the expansion tank.

I have not checked the temp at the engine. I should buy a temp gun.

Yep, handy to keep an IR gun on the boat. Even a cheapo Harbor Freight one works reasonably well.

Also, many engines have both a expansion tank on the engine, and also a recovery bottle mounted elsewhere. Want to check coolant level on the on-engine tank and not just the recovery bottle. The on engine tank should be topped up, the recovery bottle should have some in it when cold, as engine heats up the level will rise. It does not need to be full full.

Ski in NC said:

Also, many engines have both a expansion tank on the engine, and also a recovery bottle mounted elsewhere. Want to check coolant level on the on-engine tank and not just the recovery bottle. The on engine tank should be topped up, the recovery bottle should have some in it when cold, as engine heats up the level will rise. It does not need to be full full.

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Yes, both had the normal level of coolant.
The manual calls the on-engine tank as 'expansion tank' and there is an additional plastic tank next to it, with a plastic hose coming out for the on-engine tank. So, I think the coolant level was at normal level.
If I recall correctly, I did see a bit of higher level of coolant in the on-engine tank, plus few bubbles. Perhaps due to overheating. I have to test this again to see, because I am not sure, if I remember this correctly. I was too nervous about the situation. Everything happened very sudden and in an iffy situation. I had no time for proper investigation at the moment.

The new parts are being shipped, and after installing them, I will do a test run on the engine. It has to be idle warm up, because I am afraid to go anywhere and risk that I cannot run the engine on the outside waters. I moor on a buoy, so I do not have the luxury of a dock test run.

No luck. The engine is still overheating. I replaced the temp regulator and temp sender. Refilled the coolant and started the engine. It warmed up to 160F and stayed there for a while. I put it in reverse drive, while on buoy. The temp went up to 175F and stayed there a little. I took out of gear and let it run on idle. It did not move for a while, so I put it back to reverse. The temp was steady for about 5 minutes, but slowly climbed to 180. I took it out of gear again, but after 10 minutes, I engaged it again. In about 15 minutes running in reverse idle, the temp went over 180 and the alarm started to come on. I shut it down. I have taken temps with the IR meter. See photos. At this point, I don't know which way to go?

I see two sensors, but only one shows in the manuals. The lower one is the temp sender and I replaced that. The upper, smaller one with a wire connected to it, does not show in the books.
Can someone help me out and tell me what is that for? I cannot order a new one, without knowing the part number.

Leoka
It may well be that the heat exchanger for the engine and transmission are fouled. Suggest you remove both and clean them. Are there any other restriction points in the raw water cooling system that could easily be undone and checked for obstruction with debris or old impeller parts. I've seen overheats on a land based 3306 when radiator gets clogged with dirt and dust, same principal, clean out time.

Once the raw water cooling system is cleaned and checked out, if it is still overheating then the coolant pump and system need attention. Any sign of water in oil after raw water pump changeout?

sunchaser said:

Leoka
It may well be that the heat exchanger for the engine and transmission are fouled. Suggest you remove both and clean them. Are there any other restriction points in the raw water cooling system that could easily be undone and checked for obstruction with debris or old impeller parts. I've seen overheats on a land based 3306 when radiator gets clogged with dirt and dust, same principal, clean out time.

Once the raw water cooling system is cleaned and checked out, if it is still overheating then the coolant pump and system need attention. Any sign of water in oil after raw water pump changeout?

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There is good sea water flow coming out on the side. I don’t know, if there is debris in the system, but I checked the strainer, where the sea water is coming in.
Perhaps, as the temp goes up, more sea water should come in and I cannot see the difference?
There is a heat exchanger inside the expansion tank, based on the manual, which is not easy to access.
There is another heat exchanger at the hose coming out of the heat exchanger, which cools the transmission. That is easy to access, so I can start with that one. See picture.

sunchaser said:

Leokachangeout?

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Do you know what is the top sensor for? You can see it removed on my previous post.
The lower one is the water temp sender, which I replaced. I don’t know what the other suppose to do?

sunchaser said:

Any sign of water in oil after raw water pump changeout?

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No, no more vapor and the filter is clean on the top.

Does the temperature gauge show it's overheating ?? Not sure from your post.

One post you said the water temp was 160-170. That seems low. Or maybe normal until it's under a load.

Maybe it's the overheat alarm malfunctioning..

Solly said:

Does the temperature gauge show it's overheating ?? Not sure from your post.



One post you said the water temp was 160-170. That seems low. Or maybe normal until it's under a load.



Maybe it's the overheat alarm malfunctioning..

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Yes, once the gauge in the PH reaches 182-183F the alarm comes on. At 180F it is still quiet.

The 160-170F was at the beginning for a while, just idling in neutral. It slowly went up, when I put it into gear at low rpm.

Last weekend, when I did 12 hours engine run on the trip, the average temp was 160-170 all the way. Since, I have the boat, the 165-175 range was normal all the time.

182-183 seems awful low for an alarm. Did you ever find an engine book ? What does it recommend for the running temp ? What was the temp of the thermostat you put in ?
Your going to have to find the specs.

I don't have a Cat diesel and don't claim to be a mechanic. I always thought an alarm should come on around 210 + degrees. My Perkins runs around 200 @ cruise, 1800 rpm by the gauge. Maybe a little less. if your running at 180 or so I'd be surprised if that's overheating. How much higher does the gauge go ??

The sender you wanted to know about. With the key on or power on touch the wire to the engine block. If the alarm sounds it's the alarm sender.

Might be time to find a pro and see whats normal for your engine.

Solly said:

182-183 seems awful low for an alarm. Did you ever find an engine book ? What does it recommend for the running temp ? What was the temp of the thermostat you put in ?
Your going to have to find the specs.

I don't have a Cat diesel and don't claim to be a mechanic. I always thought an alarm should come on around 210 + degrees. My Perkins runs around 200 @ cruise, 1800 rpm by the gauge. Maybe a little less. if your running at 180 or so I'd be surprised if that's overheating. How much higher does the gauge go ??

The sender you wanted to know about. With the key on or power on touch the wire to the engine block. If the alarm sounds it's the alarm sender.

Might be time to find a pro and see whats normal for your engine.

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Solly
The gauge goes up to 240. I owned the boat for two years now and it was always around 170-175 at cruising rpm around 1600. I had one occasion, when the alarm went off in the past, due to raptured sea water hose.

You can see the temp of the sender on the photos. Also, the block temp and the pipe, which goes into the coolant tank.
The manual does not say anything about having two senders. I don’t know, if there is a separate sender for the water temp and another sender for the alarm? That does not make sense. I will try your recommendation next time I heat up the engine, to test the upper sender.

I do have a mechanic whom I hired before, but my situation is different now. I am not in a marina, but full-time on a buoy. The dock nearby is mostly full on the weekends, and I work all week. So, I try to fix everything myself, if I can. As a last resort, I will bring in someone to solve this issue.

I plan to clean the heat exchangers, as it was suggested earlier. In a way, it make sense to me that the overheating occurs, when there is load on the engine. Even though I have sea water flow coming out, it might not be enough to cool higher temperatures. This also explains the slow temp rise, while on idle and put in reverse, turning the prop.

I enjoy fixing things and I don’t mind the dirty work. As long I have clear directions and proper parts, I am able to take care of problems. This boat needs a lot of things, so the money will go primarily towards those items.
If I am not confident, I will hire a mechanic. I plan to visit local shops and talk to them about the options.
This engine was originally built for industry, but ended up in a boat. Its serial number does not show up, so parts are not easy to find.
Thanks.

It does sound like the alarm fires at too low a temp, but the point is, something has changed, it is running hotter, that`s a concern you are rightly trying to run down. The sea water flow is not influenced by engine temp, though I suppose it is by rpm.
What happens if you disconnect the "second" sensor?

BruceK said:

It does sound like the alarm fires at too low a temp, but the point is, something has changed, it is running hotter, that`s a concern you are rightly trying to run down. The sea water flow is not influenced by engine temp, though I suppose it is by rpm.
What happens if you disconnect the "second" sensor?

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I will not have time to test it, till the weekend. Work, work, work.

How would you test the alarm functionality? Again, the manual I have is impossible to follow. I tried.

Although, the alarm came on around 185, if I let it run more, the gauge would have gone higher really fast. At least, that what happened last year, when I had a sea water hose burst.

I'm leaning towards a bad temp sending unit on the alarm. There are 2 sensors/senders. 1 for the temp gauge and another for the overheating alarm. When it first happened this time there was a problem with the raw water pump and the alarm went off like it should. Now the pump is fixed/rebuilt and you have raw water flow. If the temp gauge doesn't climb to a pretty high temp with it running it's just the alarm sender is out of whack.

To verify the gauge check the water temp in the heat exchanger with the IR gun or a cooking thermometer. Take the fill cap off, let it run and warm up. Compare temps. They won't be the same but close. The exchanger water temp will probably be lower, that's what they do. That way you can trust the gauge and ignore the alarm for a bit. When you let it run testing see if the gauge goes over 210 degrees. If it does then you still have an engine problem.

I Googled a thermostat for a Cat 3306 and they were around 175 to 185 degrees so that's roughly what it should run at. See if you can find the temp rating of the one you put in. If the alarm is going off close to when the engine is at operating temp that's not right. Should be set a good bit higher.

The alarm sender is a simple on/off switch that's controlled by the temp of the water. When the water temp rises above it's trip point it closes and sounds the alarm. Sometimes they are combined with a low oil pressure sender too. When you start the engine the alarm will sound until the oil pressure builds up. No idea if what you have is stock or added later. With the engine running and you ground that sensor wire and the alarm sounds you will know that's the alarm sensor. No idea how to test the temp rating of the sensor or what your engine should use.