[firehoser75]

Lee,
Just curious, based on the photos and engine room layout, is that a Nordic Tug 37?
I never had the issue you are having so am not sure if you have enough room. I did have a very small leak and found that 2 oil pan bolts side by side were “slightly” loose. Tightening solved the very small leak for me. I suspect you do have the room to drop the pan, but I would not place money on it.
Good luck,
Tom

[firehoser75]

Kevin,
I had a 2002 Cummins 6BTA M3 330 hp engine. I used Shell Rotella T4 15W40 regular oil (dino oil). No problems at all, and changed oil and filter before 200 hours or once per year (whichever came first).
No need for synthetic as far as I know. Many other good brands if finding Rotella is difficult.
Hope that helps,
Tom

[firehoser75]

Tinna,
You can do it afterwards. Just fill the new one with clean oil before installing it.

[firehoser75]

I agree. Do not overfill the oil. There is a good article under Tony’s Tips here on the site regarding oil in the Cummins 6BT(A) 5.9 L engine and how much oil to put in, remarking the dipstick, etc.
It sounds like you were not able to completely drain the engine. How did you “get the oil out”?
Did you drain from the lowest point (drain plug) either into a container or the bilge? Did you use a “built in” oil change pump? Or did you use a small pump to “suck it” out of the dipstick tube?
If the later, then you probably did not get much more than half of the old oil out????
Why would you put new oil in the engine and leave a dirty filter? Change the filter as well, they are not very expensive (certainly as boat costs go). To keep everything as clean as you can, put a plastic bag around the old filter when removing to catch leaks.

[firehoser75]

I had this almost exact problem. I followed Rob’s advise and totally submerged my aftercooler with test system (under 20 psi pressure) in a large garbage can filled with water. It soon became very apparent where my leaks in the testing setup were. I attached a photo showing failed attempts to locate the leak using shaving cream. The water method worked way better. After dealing with those test equip. leaks, my test lasted overnight with no pressure drop. Definitely felt better after that. Aftercooler good to go for another few years.
Good luck.
Tom

[firehoser75]

Hi Brian,
The current owner does not know when any maintenance was done in the past?? Unless this is an estate sale, I don’t know how that could be plausible. Just saying. He might not have kept “proper records” (which I highly recommend that you start), but he should at least know when the oil was changed and fuel filters??
I have never worked on your exact engine, but did own a 2002 Cummins 6BTA 330hp engine. Being as your engine is the same basic engine, producing even less horsepower, all things being equal (meaning good past maintenance), it should have a longer “potential life” than the higher HP model. I know another NT owner (NT37) who has over 10,000 hours on his 2001 6BTA and still going strong. Good maintenance however!

If this were my boat, basing the following on what info you have provided (very little background) I would want to start with a new baseline for best maintenance (assuming it passes the upcoming mechanical survey):
– Complete raw water cooling side service of all components off engine and all components pressure tested. Fuel cooler, gear oil cooler, heat exchanger, (I am assuming there is no aftercooler), and carefully checkout the exhaust elbow and exhaust side of the turbo (if it has a turbo).
– Flush antifreeze side and replace with new coolant.
– Replace thermostat and pressure cap, as well as all engine hoses and clamps.
-Carefully inspect the raw water pump and at minimum replace the impeller.
– Replace serpentine belt and inspect all components of belt system including coolant pump. Replace idler pulley.
– Rebuild the alternator.
– If needed or no idea when serviced, change oil and filter and all fuel filters.
– Adjust valves (part of 1000 hour service).
– Ensure air filter is clean or replace with an Envirovent (from Tony).

There are improvements that can be made to this engine to make things easier or to potentially improve it’s lifespan,
– install a replacement SMX raw water pump. The stock pump is known to be problematic for several reasons and impeller changes are made easier.
-install a new gear oil cooler with anodes. Could save a future tranny replacement should the cooler fail from corrosion.
-install a manual control switch for the engine air preheat, allowing control of that “automatic” system.
-install a new idler pulley from Tony. They have failed causing big issues due to an undersized bolt.
-replace the Walker Air Sep with an Envirovent. Much better CCV system.
-maybe remove the fuel cooler (if equipped) and fuel block.
-install a freshwater flushing system!!!!!! Big time saves your raw water cooling side.
Take the time to carefully look over Tony’s Tips and research any of these suggestions on this forum for lots of info. Especially look carefully at Tony’s articles on exhaust sytems. If yours is the original, it is of the “doomed to fail” type and should be very high on the list for replacement following Tony’s advise.
With this engine being on a “Tug”, it was most likely run at around half throttle for most of it’s life, meaning it has probably not been overloaded. However, you should ensure that it will make at least it’s rated PM during your sea trial.
Good luck and enjoy your Tug!

[firehoser75]

Phil,
As far as operating at low rpm, that should not be a problem. Diesels don’t like idling for long periods of time, especially at no load (neutral).
Most Nordic Tug owners operate their Cummins diesels at approximately 1/2 throttle while cruising. That equates to 1300-1400 rpm for a speed of about 7-8 knots (hull speed basically). These are mostly turbocharged and aftercooled engines. About every 10-20 hours of operation (we usually don’t run more than 10 hours on any one day), we run up the rpm’s to 2200 rpm for 5-10 minutes, and even to WOT (2800-2900) for 1 minute at the end to “blow things out” and to check out the engine for any issues that could be developing (engine operating temp, oil pressure, alternator output, new sounds, etc.) Every once in a while, while running at the higher rpm, I go into the ER and check my engine temps at various locations using an IR gun, and I keep track of any noticeable changes, which could indicate developing problems with the cooling system.
Another NT owner has a boat one year older than mine, and he travels from Seattle to Alaska every year (19 trips now) operating as described above. He now has over 10,000 hours on his Cummins 6BTA and it is still going strong.
As far as the SMX pump is concerned, on my 6BTA it was truly a “plug and play” swap. Due to the port engine mount, I had to jack up the corner of the engine slightly and remove the mount to gain access, but it was pretty easy and uneventful.
Hope that helps,
Tom

1 user thanked author for this post.

Phil Lack

[firehoser75]

Hi Nick.
First off, most boats I am familiar with have a through hull (basically a hole in the hull) with a shut off valve. Connected in between the through hull shut off and the pump there is usually a sea strainer to “filter out” things like sea weed and other debris. The valve is usually closed or is fully open when running the engine. There is really no reason under normal operation to “partially open” it???
There are many possible explanations or causes for overheating. Starting at the through hull (hole) there could be an external blockage, for example a plastic bag on the outside covering the opening. The strainer could be blocked with debris and needs cleaning. The pump may need servicing such as new impeller or a rebuild. From there, any of the other (sea water side) coolers could have a blockage (total or partial) such as the fuel cooler, aftercooler, gear oil cooler, or heat exchanger. These blockages can be caused by pieces of impeller or “zinc” from the anodes, the build up of calcium from the sea water, or from “sea creatures”. These are all items that require regular “off engine” servicing which includes a thorough cleaning, new “O” rings or gaskets, and pressure testing. Tony suggests that the aftercooler needs this servicing every 2-3 years and the other items every 5 years. The exhaust elbow could be closed off due to internal rust build up and should be checked regularly and replaced when needed.
The coolant side (anti-freeze) could be causing problems as well. The pressure cap could be faulty, the thermostat may be malfunctioning, the coolant may need replacement (every 5 years or so when the other items are serviced) (maybe even a complete flushing) and the coolant pump may be problematic.
You gave very little info to help with problem solving. However, all of these parts need regular service. It is a “cost of doing business”. 🙂

[firehoser75]

Hi Phil,
I do not have experience with the QSB model, but did own for several years a 6BTA. I freshwater flushed my engine as often as possible (anytime there was reasonable flow at the dock).
Advice I received from Tony and others on this site:
Like Mike said keep the hose as short as possible. Also try to use a “stiffer” compared to softer hose. The softer type of hose will tend to collapse as even at idle, the engine will try to obtain more water than the 12mm hose can deliver. Try for 15-16mm hose.
Backflushing the thru hull with the valve open should be fine as the pressure is exiting the bottom of the boat, just don’t have the pressure on with the engine off and the thru hull closed. Make sure the thru hull is not completely blocked as well.
You only run the freshwater flush (for a few minutes (at idle) so even with the thru hull closed you should have enough water flow to not create a problem. However, to test this, just put your hand on the pump cover to ensure it is cold. If it is not cold (external water temp), you can flush with the thru hull partially or even completely open and it will still help.
If your Sherwood pump is the same as mine was, it has a key for the impeller. Changing the impeller was more problematic than with the new SMX pump. Also, Sherwood has a poor reputation earned through a poor track record with this pump. The SMX appears to be much better engineered and manufactured. Depending on the age and condition of your pumps, changing over to a SMX pump when it is convenient for you is better than in a strange port and you are under the pressure of a delayed trip.

1 user thanked author for this post.

Phil Lack

[firehoser75]

To remove that timing cover, if I remember correctly, just use a large slip joint pliers and give it a quarter turn counterclockwise to remove. The rest of the install is pretty easy.

[firehoser75]

I am not sure of the “rule of thumb”, but I replaced mine at about 5 years and 1000 hours. Like Rob says, it still looked not bad, but I often travel in out of the way places, and murphy will hit at the worst time, so for the relative small cost, better safe than sorry.

[firehoser75]

Hi Scott,
Removing all of the “unnecessary stuff” associated with the fuel system eliminates any problems like leaks, hoses in the way, etc. associated with this project. However, like you, when I did mine, I left the combo block in place. I just removed the fuel cooler and 2 fuel hoses. I installed a water hose in place of the fuel cooler, and had 2 new fuel hoses made up to leave the fuel path more or less the same (by passing where the fuel cooler was). All else I left as is. It worked out well, and being as my combo block was not a problem, the elimination of some of the fuel lines meant that impeller changes were made much easier. So, yes, I left the oil pressure sensor alone.
Hope that helps.

[firehoser75]

Jeff,
The clog, blockage, or partial blockage must be in the raw water path after the raw water pump, most likely after the fuel cooler. It could occur in any of the hoses or in the aftercooler (bottom cap), or the aftercooler internal water pasages, in the internal gear oil cooler passages (or the water input end), in the heat exchanger passages or water input end, or possibly in the exhaust elbow (beyond?).
Usual culprits for causing a problem are impeller pieces (often getting caught in the bottom of the aftercooler but sometimes getting further), zinc pieces from dissolving anodes (anywhere a zinc is installed or beyond), or debris build up from seawater (calcium). Since this occurred after servicing, Dan’s “stuffed rag” idea bears looking into as well.
Take the anodes out and try to look inside with a flashlight. Take off some hoses near the “best guess” locations (input ends of the various components), and go from there. If needed, you may need to take the HX and aftercooler apart to ensure no problems there, Rod out the water passages, etc., but that is the last thing I would do if finding nothing else. As Tony asked (and you have not mentioned) when was the aftercooler last totally serviced? That could be a problem if it was not done with the other items.
Good luck

[firehoser75]

Jeff,
There should only be about 15 psi in the raw water hoses, so quite low pressure. My thoughts are that either that hose is not capable of that pressure, or is faulty, or you have a blockage (partial) somewhere downstream creating this situation?? Just my thoughts, but I am not expert, so listen to Tony, Rob, etc.

[firehoser75]

Hi Warren,
I had no idea you were located in Aus. You do not list any info either in your posts or your “on screen” persona. 🙂
Now, it makes sense, and I guess you will have to look for a non-North American made device (heater), maybe even “made in Australia”??
There must be some oil pan heater products that will meet your needs?
Good luck.

[firehoser75]

Buzz,
Are you using a Walker Air Sep? If so, you might want to switch over to Seaboard’s Envirovent system. See Tony’s tips for reasons why.
First, ensure that you have not “over filled” (followed specs) your oil. Drain the oil, prefill the filter (if new) and add only 13 quarts of oil to the engine. Tony has an article about this in his tips section.
While you have the air filter off, clean the air side of the turbo (being gentle with it) as best you can. Might use a small amount of brake cleaner on a cloth??
Don’t forget that if you have a lot of “crap” in the turbo, your air side of the aftercooler will probably be “gunked up” as well, so service your aftercooler? as well (following Tony’s procedures).
Good luck.

[firehoser75]

Warren,
I don’t think so. Why would you need anything other than 120 Volt (about 2 amp) (250 watt model)? Most engine rooms have a 120 (110) outlet?
John,
The article that Rob referenced is the one I used but here is another one: https://www.sbmar.com/articles/simple-cummins-marine-grid-pre-heater-control-setup/

[firehoser75]

For what it is worth, the grid heaters on these engines are not just for starting the engine. They are also designed to “cycle” on and off as an emissions “reduction method” until the engines reach a pre-programmed temperature or are operated above a set RPM. This means that the heaters will potentially put a very large load on the alternator while cycling like this, especially if you operate other “high load” items while this is happening (like anchor windlass or electric thruster). Not good for the alternator. Also, the wiring and magnetic switches involved in the circuitry can overheat and fail.
Some boaters disable the circuit (heater) entirely. Tony has an article in his “Tips” that explains how to install a simple “on/off” switch to enable manual control of the heater. I did this (fairly easy job), and only used the pre-heater for starting (first start of the day), shutting it off right after the engine started.
If the preheat does not work, check out the fuse as well as the magnetic switches. My switches were “toast” when I got the boat.

1 user thanked author for this post.

John Muldoon

[firehoser75]

Suggestions, but I am no expert:
Ensure that you have the correct oil level in the engine. Tony has info on this in his “Tips” section, and going from memory you should only put 13 quarts of oil into the engine (prefilling the filter before installing the 13 quarts).
Change out the Air Seps for Tony’s Enviro Vent system.
That should “cut down” on the amount of oily crud in the turbo. Don’t know if it will help with the smoking issue? Possibly the air side of the aftercoolers are gunked up from all that oily “stuff” going through the system?
Good luck.

[firehoser75]

With all the potential complications with doing the flush with the engine off, I do not understand the reason one would not take the simpler route. Attaching a hose to an attachment on the lid of the sea strainer and flushing with the engine running is simple and easy. One of the first jobs after securing the boat to the dock (for me) is flushing. To be considerate to dock neighbours, I shut down the engine while hooking up. I make the hose connections, restart the engine with the sea cock open, turn on the dock water, and then close (you could partially close) the sea cock. Run for approx. 5 minutes, and shut down the dock water just prior to the engine (seconds apart)or if you have a helper, at the same time. Take a bucket with you when disconnecting the hose at the strainer to catch water that might come from the hose, and wipe up any spills with an absorbent cloth. Easy, effective, and it takes little time and effort. Each to their own, however.

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