Temperature question from the loop

[batate]

Our loop is going great and we're loving the tug. We especially loved our 2.6 foot draft in the keys.

I have a question though. The boat has started running 196 degrees when we start to run fast (e.g. > 2800 rpm). It's never come off of 185 before after warming up. How concerned should I be, on a scale from "Don't worry about it' to "Don't run fast" to "Get it serviced immediately". The coolant level is fine; I am getting good flow into the pump; I don't have a heat gun on board.

Any advice?

 

[batate]

I should add that we're in a 2014 29s, volvo penta d4, 260.

 

[gwishon]

I would change the impeller as soon as practicable. You could first try to run some Barnacle Buster through the system to remove any built-up deposits, but it’s most likely that the impeller has failed/is failing.

Gordon
2015 R29S D4-260

 

[it4llc]

Re the impeller, I was at a diesel engine maintenance class this past weekend and the recommendation was to proactively change the impeller every 2 years, if not every year. If this hasn't been done, or you aren't sure, then that would be something to check for sure. As explained by the mechanic, if the impeller does go entirely, it can end up causing even more 'downstream' problems and repairs between parts of the impeller having to be retrieved from the system and blistering inside the exhaust tubes. If you haven't already, I'd suggest also seeing if the engine raw water strainer has junk in it since that's an easy check.

 

[acdfpic]

I had the same issue with my D3 25SC on the loop last year. It would only heat up at higher rpm. I would first try cleaning out the transmission oil cooler.

It's easy to do. Just remove the clamps, take a hose and blow water through the cooler. I had a good sized wad of grasses come out. Apparently they are small enough to go through the water strainer, but will clog the oil cooler. I ended up having to do it several times on the loop.

Good luck.

Chris Boyd
RT 25SC
Destined Nomad
Gold Looper

 

[Ralf H]

Hi batate,

As already mentioned, check to make sure that the water intake, etc. is clean and clear of debris, and replace the impeller if it is time to change it. One thing, the older Volvos will increase in engine temperature when pushed to the 100% range, so I wouldn't panic if it does. Hope this helps.

Cheers,

Ralf

 

[BB marine]

We cruised last year in Florida and the Florida Keys. Different boat different engine. C26 with a D3 Volvo. The raw water cooling system is already compromised by the installation design so I always experienced a large fluctuation in engine temperature when running at higher loads and RPM. I knew what the thresh hold was. I knew what temperatures the engine would operate at at different rpms and in different ambient water temperatures. WOT would be 193F to 198F in southern Florida waters. On our return from the keys I did notice a slight increase in engine temperature. More than I had ever experienced. My maintenance schedule was impeller at every oil change which was every 100 to 150 hours depending on where I was in a planned trip or end of season of use. The impeller was at 80 hours when I noticed the issue, strainer was clear, I removed the reverse gear cooler hose and did find some grass stuck in the cooler tubes and I cleaned them. This made no noticeable change. If I pushed the throttle it would go close to derate temperature 209F. I would back off at 205F and the temp would drop quickly. ( I'm not comparing this to your issue ) The C26 has a compromised cooling system.

Here is what I found. The through hull high speed water pickup was fouled with barnacles. Not completely but enough to reduce raw water cooling flow. The fact that the through hull is already undersized this additional restriction caused the over heat. I have a friend that had a 2016 C28 with the same engine as you D4 260 hp he experienced the same thing with his engine. It would run right at 185F up to 2800 rpm then the temp would increase as high as 196F to 199F as the throttle was increased. He did the full inspection and service, impeller, cooler clean full barnicle buster flush, strainer inspection. No change! Cleaned and bottom painted the interior of the through hull pick up things got better. It still would climb to 193F at WOT. Those little critters can get into places that we don't paint or clean.

Don't disregard all the good suggestions already posted. Those are all checks that need to be done. I just thought I would tell what my findings were to add the the suggestions all readings given.

 

[batate]

I had the same issue with my D3 25SC on the loop last year. It would only heat up at higher rpm. I would first try cleaning out the transmission oil cooler.

It's easy to do. Just remove the clamps, take a hose and blow water through the cooler. I had a good sized wad of grasses come out. Apparently they are small enough to go through the water strainer, but will clog the oil cooler. I ended up having to do it several times on the loop.

Good luck.

Chris Boyd
RT 25SC
Destined Nomad
Gold Looper

I am pretty new at diesel maintenance, though I did my own 200 mile service. Where do I find the transmission oil cooler? And which direction do I blow water through it?

 

[batate]

I would change the impeller as soon as practicable. You could first try to run some Barnacle Buster through the system to remove any built-up deposits, but it’s most likely that the impeller has failed/is failing.

Gordon
2015 R29S D4-260

Thanks for the tip. What does a barnacle buster flush look like? Can I do it with the boat in the water?

 

[batate]

I found an impeller in Miami (and a backup). I also found some barnacle buster. I have a strong suspicion that the impeller is fresh, but I will open it up to inspect it.

I will also flush the system with barnacle buster. From what I have read, I mix the concentrate with water at a 1 to 4 ratio, shut off the sea cock, start the engine and keep the sea strainer full until it's discharging BB, then shut itthe engine off and let the system work for the specified time. Then, I open up the seacock and run the engine.

Did I miss anything in that process?

 

[gwishon]

The process you described is what I use. You may find it helpful to install a rain barrel ball valve/hose adapter on a 5 gallon bucket. Connect a short hose to the valve/hose adapter and put the end of the hose into the strainer. Then you can fill the bucket with the BB solution, start the engine, and open the valve on the bucket. I use this method to flush the raw water cooling system after every use.

Gordon

 

[knotflying]

Go with the two suggestions BB marine made. First check the oil cooler for grass pickup. That, IMO especially where you have been cruising) could very well be your problem. Then make sure bottom is clean and then clear your pickup,

 

[RMarkSampson]

At the RT Rendezvous at Burnt Store Marina last month - the "impeller talk" also included a discussion about how the rubber hardens up over time. Two of the impeller blades always remain in a compressed state in the housing and over time the loss of elasticity decreases efficiency. You may not have an impeller failure - but you may not be getting full flow at those higher RPMs. My engine is also experiencing the same temperature rise above 3000 rpm and replacing the impeller is on the short-list of maintenance items I am working on.

So I don't have any actual experience with this yet. My 2014 boat is new to me and I have no maintenance record from previous ownership citing an impeller replacement - so I am assuming I currently have an 8-year-old impeller installed. I have a new impeller on hand - just need to spend a few hours getting it installed. Then I'll have some actual experience on this subject.

 

[CaptT]

Check your basket in your intake. We had the same issue and always found seagrass clogging the basket, once removed our D4 returned to 185 degrees. The Keys are full of seagrass and it eventually, sometimes slowly, sometimes quickly, chokes off the intake.
We travel to the Keys multiple times each year, in fact leaving again in April, and around Florida. The Keys, and the Gulf of Mexico, have, for some reason, gotten more seagrass then we've seen in years. There is some info regarding this phenomenon on the net.
Ten years ago it was mostly in the Atlantic but because of currents, storms, etc the Keys and the Bay off the Everglades is full of the stuff. It's gotten so bad I carry two sea strainer baskets, I take out one, place in a clean one in and move on while my wife cleans the other for the next change of baskets. It works and with a clean sea strainer I never run above 185 degrees.
I have to say I always use Barnacle Buster, once a year, for a three hour flush, through both my engine and generator cooling system. It works and the stuff that comes out of the system surprises me.
We run our boat year round in Florida. Running at full cruising speed out 50 to 70 miles off Tampa Bay in July/August fishing and always hold 185 degrees on the engine temp.
I rack store my boat and flush the engine and generator after every trip yet the Barnacle Buster brings out stuff I never thought would exist in my engine cooling system.
We have a 2015 28 Cutwater with the D4 260hp Volvo with approximately 600+ hours.
Hope this helps.
Terry

 

[dclagett]

On the Chesapeake Bay I was constantly having problems with grass/debris in the transmission oil cooler and sea strainer. In 2018 I changed the factory clam shell hull strainer to a "Groco APHS Series - Perforated Hull Strainer" and have not had any debris in either cooler or sea strainer since. See pictures in my album.

 

[batate]

This weekend we were in Miami. The winds were too high to run, but I was able to do a barnacle buster treatment, and also to look at the impeller. It is pristine. No nicks, supple and soft. I was also able to check the intake and sea strainer. It's also very clean. I found two things.

1. The barnacle buster treatment (we used hammerhead) did break out some debris. So that's hopeful.
2. The zinc under the impeller (on the back side) had broken away from the screw, and there were a few chunks that drained out with it. There were also a few barnacle shells that drained out with it.

I am expecting some improvement based on what I saw. If not, I will rinse the heat exchanger, though I would prefer to wait 100 hours until the next oil change as those filters will need to come off. That looks like a project I can take on. Is there any wisdom in doing a second treatment if the problem gets incrementally better?

 

[CaptT]

On the Chesapeake Bay I was constantly having problems with grass/debris in the transmission oil cooler and sea strainer. In 2018 I changed the factory clam shell hull strainer to a "Groco APHS Series - Perforated Hull Strainer" and have not had any debris in either cooler or sea strainer since. See pictures in my album.

Dclagett, Very interested in the changing of the intake strainer. Did you work with a specific supplier to ensure proper size and flow rate?
Did you do it yourself, if so, how difficult was it and is there any helpful hints/precautions for doing this exchange?

Thank you, in advance, for any information you can provide, I am very interested in doing the same with my C28 D4 260hp Volvo.
To not have to deal with seagrass, and other trash in the water, would be wonderful!

Terry

 

[dclagett]

CapT,

I had a boatyard do the work. If your setup is like mine, it is fairly simple. On my boat, RT used a scoop thru-hull. Basically, remove the scoop thru-hull and replace it with a flush thru-hull. You may need to change some of the inside boat piping to the sea strainer. Next, the Groco APHS series perforated hull strainer is mounted on the hull overtop the new flush thru-hull. Make sure one of the mounting screws goes completely thru the hull into the bilge so it can be wired to your bonding system. On my boat, RT undersized the piping. It should have been 1.25 inches inside diameter but was 1 inch. This setup from the factory is marginal, however as long as the components are clean my engine runs at an optimal temperature.

Check with your engine manufacture or their manuals to determine the size piping for your raw water cooling system. If your boat is not setup with the proper piping size for your engine I would upgrade to the correct pipe size. The GROCO catalog will provide you with the correct perforated hull strainer based on the piping size. Larger is better, also you can get different screen hole size based on the type of debris you typically experience.

Hope this helps... Dick

 

[CaptT]

Dick, Thank you for all the great information! The bonding wire tip is something I would have never thought of, excellent info!
I'll talk to my marina manager later this week and get the ball rolling on this. Hopefully I can have it done before we leave for the Keys in mid April.
Terry

 

[GaylesFaerie]

I'm not familiar with the Cutwaters but if they are similarly built to the Rangers, then while you are in the bilge area anyway, if you have a garboard drain down there, check to make sure you have a bonding connection to that as well. My R27 did not and when trying to remove the drain plug after winter haul out, the whole drain body almost came off - all the screws holding it in place had corroded. HTH, Gary