3208 Port engine still getting salt water into the coolant.

So a year ago February I discovered that I was getting salt water into my coolant. I did not have recovery tanks so the overflow was going into the bilge somewhat un-noticed. So, I pulled the coolant bundle out and had it cleaned and repaired, but since I had to move my air con unit to get it out, I decided to buy a new Caterpillar bundle to avoid this from happening in the future. $2500. Man if I had known in advance I may have stayed with the repaired one. So after putting it in I found I was still gaining water. One our TF followers mentioned that I may have not gotten the starboard side "O" ring on properly and it was leaking. So, I took the end cap off again, replaced the "O" ring and lubed it up really well, and very carefully eased it all back together. That seemed to work. I had not been running the boat much as we were vacationing quite a bit overseas. Then I spent most of this Jan and Feb working on aftercoolers and the starboard coolant bundle. Finally I put recovery tanks on the engines and now I find that my port engine is again gaining water. What have I missed? Where else can I get salt water into the coolant? I'm stumped. I can do the end cap again but what is going to be different. No problems with the starboard engine. Did I get a bad new bundle? Is the end cap invisibly bad?

I have twin 3208s. My coolant level, that I see in the overflow tank, fluctuates tremendously. Sometimes it's way over the normal level, and other times it looks like it's low. Both engines do this. What is your evidence that sea water is getting in the coolant?

Excuse my typically long answers. Well, first the coolant visible in the recovery tank hose started looking weak compared to the starboard. That port recovery tank started to leak a little so I added some coolant to the tank. I ran the engine for some time and it got sucked back into the main tank. So then I opened pressure cap and saw that the coolant was low. I put in about 1 gallon. I'm thinking that with all the flushing I did when I first had the problem there may have been air gaps. So I also added coolant to the recovery tank to the min line. I ran the engines while taking the boat over to the pump out station and back. Then after some cooling period I looked again and the port recovery tank was at about 3/4 high while the starboard was back to the min line. So then I opened the pressure cap on the port side and the coolant was near the top. When I opened it there was no remaining pressure. Then I opened the stb and it gave a little psst. Thinking back I'm not sure if that was vacuum or pressure release. I'm taking the boat out to the islands tonight so I'll get a better idea of any water incursion.

Did you flush and add new coolant after the repairs? If so, I would draw a sample and send it out for testing to confirm if there is seawater in it.

twistedtree said:

Did you flush and add new coolant after the repairs? If so, I would draw a sample and send it out for testing to confirm if there is seawater in it.

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Totally agree. The overflow tank levels are so erratic, it would take a long time to figure it out based on these readings. I also believed I was having issues with my coolant system based on the varying levels in the overflow tank. I did have issues with the pressure caps. I replaced both as they were leaking. You would think the coolant would go into the overflow tank, but it was leaking (very slow) at the stern side of the cap and running down the engine where I couldn't see it. I now place a piece of paper towel behind the cap, so I can see if any coolant is coming out of the cap.

Perform a coolant pressure test on both engines. It's simple and quick. The devices can sometimes be borrowed or rented from auto parts stores.

heysteve said:

Perform a coolant pressure test on both engines. It's simple and quick. The devices can sometimes be borrowed or rented from auto parts stores.

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Great idea. Thanks.

I have not pressure tested nor chemically tested the port coolant yet. One reason for concern is the appearance of the fluid in the recovery lines. Port obviously less colorful compared to stbd. So I ran the port engine while pouring in more coolant and I was surprised that it took 1.5 gallons. So I closed it up and observed while we took a 50 mile trip. I didn’t gain in either engine. So I’m still watching. If I send out samples for testing who should I send it to? I have sent some to Blackstone but they didn’t really test for salt as I recall. They told me they are set up for oil testing not coolant.

Ok, I called Blackstone and they test the coolant for oil not water or salt. Caterpillar does test for chloride.

Here is an update and more questions. I finally got back to this project. My port engine coolant was all but transparent after another 60 mile trip yet I did not gain much if any in the coolant tank. So how could I be diluting my coolant if I'm not gaining. At the same time I noticed a small amount of steam coming from my port engine only. Ok, maybe two bad things at once. So last night I put dye in my coolant tank and used a presser tester to pump the pressure up to 10lbs. It took some hours but it did drift down. Then I pumped it up to 14-15 and left it over night. It lost pressure back to 10 lbs. This morning I removed the starboard HE end cap zinc and the water came out clear. Then I pulled the port end cap zincs and again it is all clear. I don't know where to check next. Pictures came out of sync so 1 is the dye color, 2 clear water from port eng port zincs, 3 is port eng stb zinc drain, 4 is the port eng coolant color compared to 6 the stb side. 5 is the pressure drift from 15 down to 10lbs. Sorry I hit the insert button twice on the dye color.

Look at the other end-exhaust manifold. Im wondering if a stethoscope might help. Pressurize the system and maybe you can locate the pinholes where the coolant and raw water is being mixed.

One test not mentioned - look at the coolant caps carefully. Some ( mostly older) are made to retain pressure while others are made to work with a recovery tank, and let coolant back in . Be sure both are the same.

Yes the coolant recovery tanks were working on both engines, rising and lowering.

I have this kit that you put dye into the coolant and then use the light to look for leaks. Worked well for me.

53351-B Professional UV Leak Detector Kit with 50W Mini Light, Black​

Comodave said:

I have this kit that you put dye into the coolant and then use the light to look for leaks. Worked well for me.

53351-B Professional UV Leak Detector Kit with 50W Mini Light, Black​

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This works well unless the leak is going into the exhaust manifold or into the raw water circuit.

I think I would try this if you have end caps on the heat exchanger.

- Drain the raw water side of the engine heat exchanger and remove both end caps so you can see through the heat exchanger. Run some compressed air and then heat through the exchanger to dry things out a bit.

- With the coolant side full, apply pressure (7 to 10 PSI) using a coolant pressure testing tool.

If the coolant appears in the dry and open raw water side of the heat exchanger it will be plain as day and you need to address the leak in the engine heat exchanger.

If no coolant appears in the open side of the engine heat exchanger you have a problem elsewhere.

The problem is that I think you are saying that your coolant is being diluted by some other clear fluid as the coolant's color is fading. The only other clear fluid of any volume present on the engine is raw water.
As I don't know the 3208 well, I'm having difficulty identifying another engine location where those 2 fluids are close to each other. Is there any?

Is your domestic hot water or space heating system coolant heated?

tiltrider1 said:

This works well unless the leak is going into the exhaust manifold or into the raw water circuit.

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Agree, but why not do the easy stuff first?

luna said:

Is your domestic hot water or space heating system coolant heated?

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This would be the only place where the water pressure is greater than the coolant pressure. I'd pull a coolant hose off of the water heater and see if water comes out steadily.

Well I have no connection with between the heater and engines so that is not it. I pumped the pressure up to 20 lbs and left over night again and the was only a very small pressure loss and again no dye in the end caps. My Cat mechanic suggested I take the boat out for a run and look for coolant in the exhaust. The dye I'm using does light up with UV but I don't have the light. I think I need to get one, run the engines up to temp in the evening, then check the exhaust with the light on my return. That would only explain the loss of coolant but not the dilution. In the mean time it looks like my turbo has died probably from the water coming through the exhaust. This is really getting fun.

I think you might be chasing shadows. You had no loss of coolant, just a change in color, right? It seems more likely that the coolant has just become more thoroughly mixed. Otherwise you would have to have two problems; water leaking into the coolant, and coolant leaking out through some undetectable path, and those two leaks would have to be exactly the same rate for the level to stay the same. That seems very unlikely.

Yes I understand what you say and if it wasn't for the fact that I saw the coolant color change over the course of months I might agree. Oh, also the facts that now at 1750 rpms my port engine is producing steam while the stb does not. Also, the fact that evidence indicates a failure of the port turbo. So that explains that there is coolant leaking but where is it coming in. Here is something historic. I was seeing my coolant getting weaker over a year ago so I assumed it was a failed coolant bundle. So I bought a new one. Put it in and I was still getting water incursion. So one of you fine listeners suggested I may have not installed the stb end cap and "0" ring properly, so I redid it with care. Then I still had the coolant getting weaker. So I re-did it a couple weeks ago. This time I polished the coolant bundle fitting that the "0" ring slips over and I lubed the heck out of it and it went on nicely. Maybe that solved my coolant dilution problem. Pressure testing is not showing any issues. I am going to add more dye and run the engine and look for more issues. Boy this is the fun part of boat ownership. NOT.

The only place you can get the dilution is at the coolant and raw water connection. Normally your Heat Exchanger . While running due to the pressure of the water pump you get water intrusion, Normally under cool down you get coolant loss ( if the cap is left open )
You need to verify it is good.

I don't have the 3208. I did a quick search on the cat 3208 cooling circuit. Its pretty basic, a typical 2 bypass system.

To test on the assembly on the engine I would simply

Leave coolant in the engine.
remove the raw water hoses ( both ) on the right side.
remove cap and install pressure . use a radiator pressure tester like
pressurize to 40-60 lbs
leave set over night .
put a catch container under the open raw water lines. If the pressure decreases or you see fluid coming out the raw water side you problem is in the assembly or the bundle itself.

I'm not saying it's not happening, however it seems odd. TMK the closed cooling is at a much higher pressure than the raw water cooling. It has been my experience that if there are holes in the heat exchanger, the coolant tends to flow to the raw water cooling side, and out the exhaust. You have raw water from a low pressure system somehow leaking into a higher pressure closed cooling system?

That doesn't make sense, however I am not a mechanic.

Shrew said:

I'm not saying it's not happening, however it seems odd. TMK the closed cooling is at a much higher pressure than the raw water cooling. It has been my experience that if there are holes in the heat exchanger, the coolant tends to flow to the raw water cooling side, and out the exhaust. You have raw water from a low pressure system somehow leaking into a higher pressure closed cooling system?

That doesn't make sense, however I am not a mechanic.

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That is exactly what is happening , however when the system cools down, The cap is on , a vacuum is created and it draws the salt water into the cooling system diluting the coolant and keeping it full.

Comodave said:

Agree, but why not do the easy stuff first?

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Yes, you are right. I thought I had agreed with your original post.

Sounds like raw water is the only possible source of makeup water, right? In that case I'd have the coolant tested for traces of salt water.

Could the coolant color be changing for some other reason? The pictures posted earlier of two jugs of coolant looked the same to me, and I think one was port engine and the other starboard.

Is your turbo coolant cooled? Some are and some aren't. You say there are indications of a turbo failure. When pressure testing, have you inspected the turbo inlet and outlet for traces of coolant?

The pictures of the "empty" jug was where I mixed the coolant dye and I accidentally added the photo twice. Look at the coolant color in the the two clear recovery tubes. One bright red, one you can't hardly see color. That took a lot of time to happen. And even after seeing it happen, I thought maybe there was some water in the engine from my flushing and I added a total of 2.5 gallons of fresh coolant over two times. Then the coolant color kept getting lighter. So, there is no doubt that sea water is getting in. Yes I could test it but why, its obvious. Since before I pressure tested the HE I re-installed the stbd end cap, maybe that was always the source and now it is corrected. But, just to be sure, I'm going to add more dye to the tank, I have on order a UV flashlight, I'll run it up to temp in the evening and look at the steam for UV dye and any place else around the engine room as well as again testing the water coming out of the end cap zinc holes. If the incursion is fixed I need to get back to "where is the coolant going" problem. Those who have followed some of my other posts know that I also serviced my after coolers. The port side was very difficult to remove. I thought it possible that I cracked the cooling supply nipple on the after cooler core and water is getting into the engine there, but that is not coolant, it comes straight from the water pump then to the coolant bundle but it would explain the steam and ruined turbo. I will get to the turbo later as it is failing. Running just the stbd engine I can hit 2400 RPMS with no steam no smoke. Running just the port I only hit 1950 RPMS with black smoke. Turbo repair parts won't be available until November so I need to fix the water incursion and the expected water in the exhaust first so I don't burn up another turbo.

The dilution of the coolant could be as you suggest a leak in the engine’s coolant heat exchanger where the coolant under pressure migrates into the raw water circuit and gets spat out the exhaust, only to get refilled under the vacuum created once cooled down.
This is a pretty delicate dance to remain full but the fact that you added 2.5 gallons of coolant a while ago makes this seem more likely.
Raw sea water in the coolant can affect the coolant pump, T stats, coolant passages and anything else that is in the circuit but the damage if caught quickly is limited.

Raw sea water in the charge air either from a leak in the turbo seal or the difficult to remove after-cooler core is a much bigger deal as it can affect valves, pistons, rings, bearings and the list goes on.

Doesn’t this engine model have a history of head gasket failures?

In order to stop further damage you need to find the leak(s) and fix them without delay.

If Blackstone cannot test coolant then get a Cat SOS sample kit and ask for the coolant sampling kit.

Get a UV or Blacklight flashlight. Lot of folk have done that and successfully. I have never needed them except for playing but I have 3 of them for other reasons. They are not expensive. I got mine from Home Depot years ago.

Do the checking when the E.R. has darkened so the light has a better chance of showing something. If there is too much light it may not show well if at all.

Let the engine sit but don't expect results immediately. THe engine heat could boil any leakage away quite quickly. Watch soon after but it may take some patience for the engine to cool a bit and stop boiling away the coolant and IR trace. and you to do a repressurize.

Look again next morning for traces of the die to show up.


Pressure test the exhaust mfld. if not already done. They generally will dump upon heat up from running and a crack opens up that only seals when cold. THey may require a water bath heating to open a crack when off the boat.

Good hunting.

.

Seems to me that I would be looking for the source of the steam to see if it was related to your cooling problem.

First would be to measure raw water flow at the exhaust. With a five gallon bucket, and the engine in neutral, I would measure the time it takes to fill the bucket at maybe 1,800 RPM. Then compare it to the other engine.

Assuming low flow is generating elevated temperatures and steam, I would find the source and resolve that issue. Maybe it causes the coolant issue, maybe it doesn't.

Ted