Raw Water Pump Belt Tensioner

dclagett

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Joined
Aug 9, 2016
Messages
498
Fluid Motion Model
C-26
I need to replace the raw water pump belt tensioner on my Volvo Penta D3-150. In trying to get the necessary parts does anyone out there know if the belt tensioner can be replaced without removing the water pump pulley assembly? I don't have a new o-ring for the pulley assembly and to get one I need to buy the impeller kit for $63. It is only a single bolt that holds the belt tensioner to the engine. I was hoping after removable of the bolt I could slide the tensioner from behind the pulley.
 
Hello dclagett,

Sorry to hear you're experiencing some issues with the belt tensioner on your Volvo D3-150. I've unfortunately seen this issue before as it sits below the impeller housing. When changing the impeller it's important make sure to rinse the tensioner afterwards with fresh water. You could also close the seawater valve and run the engine for 5-10 minutes with fresh water before swapping out the impeller. The belt tensioner part number is: 21424647. To replace, you'll want to remove the belt first, then there a single allen screw holding it in place. Once the bad tensioner is removed, you might try soaking it in some penetrating oil and see if that fixes it before purchasing a new one.

Give me a call at the office with any questions at all: (253) 839-5213.

Thank you,

Tim
 
Tim,

Thanks for the advice I will try some penetrating oil. Due to a wrist injury I had a "certified" Volvo Penta mechanic change the raw water pump impeller last week at the same time he updated the engine software. He did not rinse the tensioner with fresh water afterwards. One would think VP would know about this issue and train their mechanics better. Oh well, thanks to the Tugnuts site and our boat manufacturer that provides an excellent resource for the owners.

Thanks again,

Dick
 
I have just replaced a water pump tensioner on a 2016 R-27 with only 190 hours on the D3-200 engine. Same problem with the tensioner seized up.
 
Yesterday I was able to free up the tensioner by spraying CRC into its casing. Seems to work for now, however I plan to replace the unit. I have the local VP dealer checking with VP if this part is covered by the 5 year warranty. Probably not covered but it is worth the effort before I spent $200. In the future I plan to remove the tensioner prior to replacing the raw water pump impeller. A little extra effort every 2 years to minimize a breakdown and save some $$.
 
The impeller replacement is done in tight quarters on Ranger Tugs and Cutwaters so the concentration is focused on impeller removal and assembly. I few extra steps in a planned impeller change can reduce belt tensioner failure. Do an engine flush with fresh water before impeller change. It only takes a 10 minutes of running before changing the impeller. This insures that any water draining out of the pump housing draining into bilge and spilling on to engine components is fresh water. Next take a few shop towels and lay under the pump housing, and into bilge area to absorb water and also catch any screws or tools that drop into the bilge. Remove the belt by reducing the tension from the belt tensioner. After removing the belt spray CRC 3-36 on the belt tensioner to protect it from any water that is splashed on it also protect the tensioner housing with a rag. After the impeller change is done spray the tensioner again to help prevent it from rusting and locking up. I also spray the engine mounts, shaft log, seacocks and once a year when I grease the rudder log I spray the steering cylinder and the cylinders connection fasteners. We use the boat mostly in fresh water so this may be overkill but we plan on salt water usage also. I worked as a marine technician for 4 years in the New England area. A spray bottle of CRC was standard equipment. I would think that the tensioner would be under warranty. The engine is a marine engine. The components should be manufactured to withstand the elements of the marine environment, Salt air and moisture. Hopefully Volvo will stand by their product and replace it.
 
How are you accessing the front of the engine on your 25 SC ?
Removing panels back side of steps into cabin area?
Also just had my service completed and authorized Volvo dealer checked and stated no update to software on D 3 150 hp, looks we purchased our 25SC's about the same time.
 
I had the first full season service on our d3 - 150 done by the local VP guys last fall. They changed the impeller since it seemed logical having got as far as disassembly for “inspection “. I’m sure they didn’t spray the tensioner with anything. In light of the issues that people seem to be having in salt water I am wondering whether there is merit in removing the panel under the step etc. to gain access and then spraying the tensioner with CRC as a preventative measure. I normally wouldn’t look at doing this before next November when I will do the annual service myself.

Advice much appreciated.
 
da156mac,

There are a couple videos that show an impeller change on an RT27 & RT25SC that you can view. Google "Ranger Tug impeller change" and you should find them. Basically to gain access to the area remove 3 panels: 1 in front of the step, 1 on the side of the step and the last one under the step. If you have the optional cabin heater you will find its fuel pump attached to the panel under the step. One of the videos will show how to deal with the pump.

If your D3 engine needed the software update a letter was sent to the registered owner. I found out that I was not the registered owner for my engine when I received the letter forwarded from the previous boat owner. I had the Ranger Tug dealer where I purchased the boat contact VP and correct the ownership. Also when I went to the VP dealer to get the required SW update they told me it did not require any update. Apparently this SW update may not be well known by the VP dealers and may not be flagged in the VP database for your engine. I called VP Customer Relations in Norfolk, VA and they were able to verify that my engine did require the update and requested the VP dealer to perform the update. The VP Customer Relations person is Dana Hatton, phone 866-273-2539. Good luck!

By the way the SW update eliminated all smoke on startup.

Chimo,

I would assume that the mechanic that changed your impeller would have told you the tensioner needs replacing if there was a problem. It is not too hard to check by removing all the panels to gain access to the front of the engine. Then take a 17mm socket wrench and place it on the bolt that goes thru the center of the tensioner wheel/pulley. Rotate the wrench clockwise and the wheel/pulley will drop down releasing tension on the belt. Then release pressure on the wrench and the wheel/pulley will come up reapplying tension on the belt. Make sure the belt is still correctly on the raw water pump and crankshaft pulleys. If the wheel/pulley remains down your tensioner is not working properly and probably needs replacing. Apply CRC to the tensioner using the supplied tube to direct the fluid to the front, back and openings in the housing. It is probably not good to get CRC on the belt or pulleys, so be careful. Brian from bbmarine may provide some better advice, I am an amateur mechanic.
 
dclagett

Many thanks for the info. Since the tensioner was only checked last December I think I will leave it until I service at the end of the year. I doubt it will lock up that fast.

All the best
 
I attempted to replace my impeller today (Volvo D-3 150) and discovered my belt tensioner is frozen. I could move it to get the belt off but it did not spring back and apply tension. It moves with a breaker bar but does not move back to the tension mode on its own. I removed the tensioner and soaked it in PB blaster. It does not free up. This is 2015 fresh water boat stored in a temperature controlled garage with less than 200 hours on it. There is no evidence of any significant rust or corrosion. It looks like a design or manufacturing flaw. Does anyone else with this problem know if the design has improved or if the part is covered under the 5 year warranty?
I pulled the original equipment impeller and other than a minor set, it appears as good as new. It spends the off season sitting in antifreeze which I put in for the winter in the event we have a power outage.
 
S. Todd,

I agree it is a design issue. According to my VP dealer it is not covered by the 5 year warranty. I used CRC and WD40 and that freeed it up some. I have run the boat for about 8 hours since with no problems. I ordered a new one from the VP parts store online ($200) and just received it last week. I plan to install the new one this week however I am trying to find out the torque value for the bolt that holds the tensioner to the engine block. From looking on line at other tensioner installations it looks like 35 nm. Do you have any information on the D3 torque value. It is a steel bolt going into an aluminum block, so I want to be careful with tightening the bolt.

Dick
 
I do not have any info on the torque to use for the install bolt. Mine came out without much force so 35 NM might be a little more that I would expect. You are correct that it is a Steel bolt into aluminum. I think that calls for an install with anti seize lubricant but the original appears to be installed without any. The tensioner appears to move on a nylon bushing so I am wondering if regular silicone spray on the new one is called for. CRC and PB blaster did not work for me. I plan on ordering a new one Monday. Can you tell if the new one is designed any differently? I checked our alternator tensioner, which has a different design, and it works as it should.
 
The new one seems to have the nylon bushing where the old one is metal. It came just as we were going out of town for the weekend so I did not have a chance to look closely. I should be home Monday and will post pictures in my album.
 
The manual that I read states
Belt tensioner,

drive belt ........................................ 35 Nm Seawater pump tensioner and Alternator and closed cooling Pump tensioner.


toothed belt .................................... 27 Nm. Timing belt tensioner

35 NM is round up is 26 ft-lb

If the bolt is close to a 3/8" bolt Grade 8 the equivalent would be 10M 1.5 max torque 55 Nm/40ft-lbs in cast iron .........40NM/30ft-lbs in aluminum , given this I believe the 35 Nm is a good spec.
 
Brian,

Thanks for the information and analysis. I assume it is best to use a good marine grade nonmetallic anti seize compound on the bolt threads that attach the tensioner to the aluminum engine block. Any recommendations?

Thanks... Dick
 
If you are looking for anti-seize I have always stayed away from it because it has different metal compounds in it. There is a marine anti-seize MARINE GRADETM NON-METALLIC ANTI-SEIZE good to use on aluminum blocks or any other assembly or bolting on boats, docks, trailers.

I use Johnson Evinrude BRP Gasket Sealing Compound 0508235 on bolts that I thread into aluminum. This is all I use when bolting parts to an outboard. I use it for gaskets, bearing housings and bolts in lower units. It lubricates, seals, and protects the threads.
 
Brian,

Thanks for the suggestions.

S. Todd,

I have put pictures in my album of the new belt tensioner. The main difference is the gray on the first picture is some sort of nylon, whereas on the my original tensioner this area is metal and somewhat rusted. I have not removed the old tensioner to compare side by side so there may be additional differences. Sounds like your engine may have the same tensioner design as the new one I just received from VP. This may not be good news for us since I was able to get the old one somewhat functioning again using penetrating oil. This allowed me to continue to use the boat until the new part arrived. Oh the benefits of progress.
 
Dick,
Your new tensioner looks just like the original equipment one I took off my 2015 R25SC (less the Volvo green paint). Lets hope they did something different in the interior design work. At least yours has sprung back to the position that allows it to apply some tension. I shelled out the $200 for a new one today from the Volvo Penta on-line parts store (that only comes to $1.70 per hour of operation -who would have thought a belt tensioner was a disposable part.) I owe you a thanks for your galvanic isolator install pictures - did that project last month and it looks remarkably similar to yours!
Todd
 
S Todd,

I went to the boat today to changeout the belt tensioner. I removed all the panels, crawled into the step and went to take the belt off the raw water pump. Guess what, the old tensioner is working perfectly. So it appears the penetrating oil finally did its job and freeed up the tensioner internals.

If you haven’t replaced yours yet you might want to squirt more WD40 inside and try to exercise it if possible.

Dick
 
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