D6 435 Impeller Change

[dbsea]

I just want to vent about how difficult this task has proven to be on my C-30 CB. I would not wish this on my worst enemy. Firstly, I ordered the wrong impeller (for the 440 version), and accordingly the wrong impeller puller as well.

On to the work itself, which is currently paused due to the above parts debacle, including the $110 impeller puller. There are 6 10mm bolts that need to be removed from the front plate of the seawater pump to get at the impeller. It requires midget hands, a micro ratchet, and contortionist body movements to get all 6 bolts out, after disconnecting the fuel filter water sensor. Obviously the sea cock was off, but still enough water came gushing out of the hose and engine to run the bilge several times over and get me and the engine compartment soaking wet. Did I mention I lost one of the 6 bolts to the nether regions of the bilge, even after repeatedly telling myself not to drop it? Will never see that again but thankfully the proper impeller kit from Volvo comes with two extras. I really hope that this is the worst of the regular maintenance tasks I have to do. I needed several beers to console myself after I finally gave up for the day yesterday…. <<rant over>>

 

[GaylesFaerie]

WRT losing parts in the bilge... I don't remember who, but someone on Tugnuts suggested draping a towel under the engine where you are working and over the bilge. It works great on my R27 with the Yanmar 180. Ooops! <curses>, oh wait, there it is, thank you very much. Maybe that will work for you? Can't help with the large number of bolts or water. Gary

 

[dbsea]

The towel is a solid idea. I tried with a shop cloth and it was not enough. Perhaps a junk towel and some clips of some kind!

 

[Submariner]

Wish I could have video'd all that. Sounds like the making for a great video! ha!

When I was mounting the solar panels atop my boat... that is literally all I thought about... dropping the solar panel overboard, dropping a bolt or mounting bracket overboard, my tools overboard... balancing on the top of the boat in my slip, I worried about me falling overboard! Slow and steady. The boat teaches me patience with every project. And even at that, sometimes bad things still happen and I get to learn all about self-control. haha.

LaZina's great at editing out any foul language I may mutter. 🙂

 

[dbsea]

In hindsight it was definitely amusing. In that moment, not so much...LOL. Looking forward to the parts getting here so i can get it all back together and use it this weekend. 🙂

 

[Cessna172]

I feel your pain... The impeller is without doubt my biggest "dread" when doing the annual maintenance.

Unfortunately, I bear more difficult news - the installation is significantly more frustrating. I am not familiar with the engine layout of the D6 as mine is a D4. So I am speaking in reference to the D4.

The impeller replacement process can be made much easier if done at the same time the Secondary Fuel Filter and Oil Filters are being replaced. On the D4, much easier access is available with these filters out of the way. I use Doggy Pee Pads spread out beneath the engine to catch hardware and oil/fuel leaks. The one impeller bolt I sacrificed to the bilge was recaptured with a mechanic's extendable magnet.

I have never used an impeller puller; as a pair of 90 degree needle nose pliers does the trick. Takes some yanking, but you ought not be concerned about damaging the old one as it'll get tossed. Clean the impeller casing with rags/compressed air, liberally apply Glycerin, then install the new impeller (vane orientation doesn't matter as the vanes will properly align as soon as you start the engine to test for leaks).

Now for the seventh level of hell - the installation of the O ring. Seems innocuous, trivial, but be warned if the D6 has the same "snowman" shaped O ring groove as the D4 it can be an extinction level event. The O ring must be inserted and retained in the groove before installing the cover plate. Here is were the problem lies - it does not fit...
You may swear the O ring is simply too big as there seems to be some "left-over" every time to struggle to install it. It continuously pops out, requires four sets of fingers, until finally it relents and seats in place. Joyfully you the install the cover plate and quickly discover the O ring has popped out once more and time to start over.

Most helpful hint - fill the groove with grease before installing the O ring. The grease really helps the O ring stay in place when installing the cover plate.

Thought it was difficult removing the cover plate bolts, the installation can be worse as now we need to get our clumsy fingers into the deep recesses and get the 10mm bolts started. Once the bolts are started tighten the cover plate evenly.

Always start the engine and check for leaks. That nasty O ring mat not be done with you yet.

Hope this helps,
Gary

 

[dbsea]

very wise words Gary, thank you. The layout of the D6 engine is a bit more forgiving, as the sea water strainer hose to the engine runs along the port side of the engine bay, and directly connects to the sea-water pump. The on-engine fuel filter is only minorly in the way, and I can work around it. Great advice on the grease, I actually got some for that exact reason because I was concerned about the o-ring. I will also find a mechanics magnet... lord knows what else i'll find down there in the bilge 🙂

 

[HawaiianFish]

Ugh I am not looking forward to this but appreciate the post, as it is much better to be mentally prepared for the impending “suck”. I am also going to buy an extendable auto magnet stick thingie right now to keep on the boat for the inevitable loss of something in the bilge.

 

[GaylesFaerie]

FWIW, before changing the impeller, I make sure to have a clean bilge. That really helps too to get a visual sometimes. G

 

[BB marine]

All great Idea's all ready posted. I will add a few tips that may increase the scope of the job but also include general preventative maintenance procedures along with the job.

*If the engine is operated in salt water I always prefer to run and flush the engine with fresh water before opening up the pump. This prevents salt water spills. This may seem like over kill but I have seen fasteners and metal components in the engine compartment rust and corrode quickly from a direct contact with salt water.
* The pump belt is to be inspected and adjusted in the same interval as the pump impeller (every 200 hours) Loosen the belt tensioner and remove the belt. This will make removal and installation of the impeller easier. This will allow you to turn the pulley as you walk the impeller out of the pump housing and walk the impeller into the housing during installation. Impeller orientation may not be that important as stated it will flip to correct orientation when started. I have always installed in the correct orientation (why not??) It is easy to do and remember, impeller turns the same direction as the engine rotation.
* When the impeller is removed inspect the pump housing for wear, check the inlet and outlet grates for wear, burrs or sharp edges, check the housing liner for deep grooves that may reduce the pump efficiency. If all looks good proceed by applying a liberal amount of Glycerin into the surface areas of the pump to help lubricate the impeller for installation and the dry start when commissioning the new impeller. Place the impeller into the pump housing and apply some forward pressure until the shaft splines start to engage with the impeller splines. Start to turn the pulley, as the impeller engages with the pump splines it will begin to turn maintain pressure pushing it in and it will slide right in place. Turn the pulley a few times with the impeller installed to confirm proper installation and vane orientation. Next install the O-ring. My trick for o-ring installations is Vaseline Petroleum jelly. I place the Vaseline in the freezer or cooler for a while, this gets the lubricant hard and it will maintain good holding of the 0-ring. I fill the o-ring groove with chilled Vaseline then place the o-ring in the groove, install the cover.
* Inspect the belt for cracks, cuts and excessive wear. Inspect the pulleys for rust. Check that all pulleys are tight and bearing are in good condition. (NO END PLAY OR DEFLECTION) idler pulleys turn freely with no rough spots when turned. If you have a older D4 or D6 that has cooling system anodes this is a perfect time to replace them. The engine was flushed with fresh water and mostly drained when the impeller was removed so removing the anode now for replacement is a good time. The belt removed gives better access to the exchanger anode for removal and installation.

*Install the belt as per the owners manual and adjust the belt tension.
Adjusting/changing drive belts.
The standard generator and water pump are driven by a poly-V belt.

Change/tension the belt as follows:
1. Undo the bolts on the tensioning roller bracket. Remove and change the belt if necessary.

2. Tension the belt to apply a torque of 70 Nm on the tensioning roller square fitting. Secure the tensioning roller with the bolts. The bolts must be torque tightened to 50 Nm.

3. CHECK BELT TENSION AFTER A FEW HOURS OF OPERATION. CHECK PUMP COVER FOR LEAKS AFTER STARTING THE ENGINE

As Cessna172 stated having the fuel filter and two oil filters removed while doing the impeller change will aid in room and accessibility. A complete preventative and annual maintenance done at the same time sometimes will save time in the long run.

 

[dbsea]

Thanks for chiming in Brian. I had all my belts replaced in December when I had my last oil change, so bad timing on that one. Regarding the flush, that does probably need to be done but my boat is stored in fresh water here in Seattle and I typically run out/back to the salt, so thankfully the water that spilled out to the bilge was fresh. Appreciate all the other tips. The proper replacement impeller (and bolts) is on the way, so hoping to have this wrapped up this week.

 

[dbsea]

I managed to get this done last night! Turns out the impeller puller tool I got was basically useless due to space constraints, and two pair of needle nose clamp pliers was actually way more useful to remove the old impeller. A lot of glycerin and brute force was the best solution for getting the new one back in. Still waiting on a replacement M10 bolt, I wasn't able to retrieve the one I dropped in the bilge despite repeated attempts with a magnet. As annoying as this process was i'm glad to have learned how to do it and get advice from y'all.