Volvo Penta D4 (& D6) Fresh water flushing

[GrahamHR]

One of the many advantages of keeping my boat in a Drystack . I flush the raw water side of my D4 either immediately after use or within 48 hours of lift out.

What do you use to/ where do you introduce the fresh water ? the muffs I have that worked on the1999 DPS I had certainly wouldn't work on the DPH, even if I got into the water to fit them !.

 

[GrahamHR]

I haven't got my boat yet - expecting it very soon, but I think D4 uses 38mm id hose (think D6 may be 50mm?)
If you Google Adit marine (Australian), they do a kit with motorised valves which looks good. However this doesn't shut the inlet seacock, it just injects fresh water at hose pressure upstream of the inlet. Trying to figure out if this would be effective enough?

The Adit T piece and valve look good, but a little pricey perhaps by the time shipping, import duty and VAT is added.

I understand your concern; as the inlet on the drive is still open, you wouldn't know if it was "pure" fresh water that was passing through or a mixture of salt and fresh. At our marina, the water pressure and flow capability is very high. Judging by the lank of buildup in my previous engine, I think the fresh water pressure and flow was high enough.

 

[beejay190]

What do you use to/ where do you introduce the fresh water ? the muffs I have that worked on the1999 DPS I had certainly wouldn't work on the DPH, even if I got into the water to fit them !.

This is what I use plus a cork to to block the water inlet below.



I keep an eagle eye on the temp guage, raw water strainer and water exhaust whilst flushing.

[ I hope the link works. Please let me know if it does not ]

 

[GrahamHR]

This is what I use plus a cork to to block the water inlet below.



I keep an eagle eye on the temp guage, raw water strainer and water exhaust whilst flushing.

[ I hope the link works. Please let me know if it does not ]

Thanks. I see how the rectangular muffs would work ( I never knew such a thing existed, the ones I have are circular). What/ where is the other inlet you are referring to, the one you block off with a cork ?

 

[beejay190]

Thanks. I see how the rectangular muffs would work ( I never knew such a thing existed, the ones I have are circular). What/ where is the other inlet you are referring to, the one you block off with a cork ?

The cork is just visible in the picture blocking the water inlet underneath. Just to the right of the skeg where the hose clips on to the muffs.

[ Cork kindly supplied by GeoffS of this Forum ! ]

 

[GrahamHR]

The cork is just visible in the picture blocking the water inlet underneath. Just to the right of the skeg where the hose clips on to the muffs.

[ Cork kindly supplied by GeoffS of this Forum ! ]

Thanks; I never knew there was an inlet there ! (I had always assumed the water went in through the visible inlets, which always seemed very small to me !)

 

[trialframe]

The D4's on my new boat are driving shafts, so the boat obviously has conventional water intakes with seacocks.
The only two places to introduce the fresh water would be 1.Between the inlet seacock and the engine mounted water pump or 2. By mounting a valve controlled inlet into the strainer cap?

 

[GrahamHR]

I would expect the best place would be in the hose between the seacock and the sea water pump.

 

[Fmicol]

I would expect the best place would be in the hose between the seacock and the sea water pump.

I just bought un new boat fitted with a volvo D 4 and i would try to do such a system for fresh water flushing did you find a solution and install it?

 

[GrahamHR]

I just bought un new boat fitted with a volvo D 4 and i would try to do such a system for fresh water flushing did you find a solution and install it?

Yes, I did. I used a T piece in the inlet hose (https://www.carbuildersolutions.com/uk/black-nylon-stepped-t-piece-3538mm-2219mm), stainless steel ball valve, hose nipple and clamps. The ball valve inlet has a male Gardena type coupling and cap. that clips on. The valve is attached to a stainless steel flat bar, which is attached to the engine using the water pump bolts.

I used 19mm ID heater hose, 22mm would have been better perhaps as it could have been double clamped ( the 38mm original hose is double clamped). Overkill maybe, as the flushing system on my V8 petrol was similar and that was only singly clamped. ( never had any leaks or loose clamps .in the 9 years I had it

 

[Fmicol]

Many thanks,

my engine have a raw water filter did some bodu try to open the cap of this filter and introduce the frefh water directly in the filter?
MAnt thanks
François

 

[jrudge]

Yes. I have done it as has MAPISM. He leaves his in all the time, mine I just put in when i need an end of season flush.

EDIT - Having just read your post to clarify we both had new perspex lids made and put a valve and hose fittings on it

 

[jdrakeford]

Hi,
I have recently bought an Aquador with a Volvo Penta D6 310 DPH-A (outdrive). I have just done the heat exchanger, after cooler and lub oil cooler. I wasn't to impressed with the condition of it all! Now it's all nicely overhauled and fitted I would like to be able to fresh water flush the system when not in use. I see comments in this tread regarding installing a valve on the line into the raw water pump with tee peice and hose connection. On the D6 the pipe is 2" so quite big. It's very tight for space on my boat to get a big 2" ball valve plus a tee piece and hose connection fitted. What I'm thinking is to install a tapping with hose connector on the sea water strainer lid which is after the sea water pump. Flush through there and the impeller will prevent most of the back flow. I have thought about the risk of water into the engine through the exhaust elbow but don't think this is possible with my set up. I'm thinking this would only be an issue on an engine with muffler/ water trap. Any thoughts / suggestions appreciated!

 

[kashurst]

The D4's on my new boat are driving shafts, so the boat obviously has conventional water intakes with seacocks.
The only two places to introduce the fresh water would be 1.Between the inlet seacock and the engine mounted water pump or 2. By mounting a valve controlled inlet into the strainer cap?

Have a look at ASAP supplies - they sell all sorts of boaty bits. You should be able to find what you need.

 

[MrB]

Hi,
I have recently bought an Aquador with a Volvo Penta D6 310 DPH-A (outdrive). I have just done the heat exchanger, after cooler and lub oil cooler. I wasn't to impressed with the condition of it all! Now it's all nicely overhauled and fitted I would like to be able to fresh water flush the system when not in use. I see comments in this tread regarding installing a valve on the line into the raw water pump with tee peice and hose connection. On the D6 the pipe is 2" so quite big. It's very tight for space on my boat to get a big 2" ball valve plus a tee piece and hose connection fitted. What I'm thinking is to install a tapping with hose connector on the sea water strainer lid which is after the sea water pump. Flush through there and the impeller will prevent most of the back flow. I have thought about the risk of water into the engine through the exhaust elbow but don't think this is possible with my set up. I'm thinking this would only be an issue on an engine with muffler/ water trap. Any thoughts / suggestions appreciated!

There are a few threads on here on how to do it, Mapism and JFM have the copy rights lol. Search for BodgeFlow ™©® I think all you need to know starts in this thread, page 3 post #41 Engine cooling thermostat, how does it work

 

[jdrakeford]

There are a few threads on here on how to do it, Mapism and JFM have the copy rights lol. Search for BodgeFlow ™©® I think all you need to know starts in this thread, page 3 post #41 Engine cooling thermostat, how does it work

Thanks Mr B, the strainer on my D6 is after the sea water pump, if i tap in on the strainer lid, flushing would have to be done with the engine stopped. But as far as i can see there would be no risk of water backflowing into the engine through the exhaust elbow with the D6 setup, unless anyone knows otherwise?

 

[MrB]

Thanks Mr B, the strainer on my D6 is after the sea water pump, if i tap in on the strainer lid, flushing would have to be done with the engine stopped. But as far as i can see there would be no risk of water backflowing into the engine through the exhaust elbow with the D6 setup, unless anyone knows otherwise?

Drop @MapisM a pm, he knows how to do it. There maybe a better thread than the one I posted as it was talked about at length by MapisM and JFM.....It's on here somewhere and MapisM will know where to find it.

 

[MapisM]

MrB, actually the thread you already linked is the one where the matter was discussed in more details, and there is nothing I could add that wasn't already discussed/explained there.
But that was based on a typical setup, where the strainer is upstream of the engine raw water pump.

If in jdrakeford boat the strainer is downstream of the water pump, the system couldn't work as described in that thread.
And I would NEVER flush the engine while stopped, by sending through the raw water circuit pressurized fresh water.
Actually, depending on the specific engine and exhaust design, such system could work flawlessly.
But without having a bulletproof assurance that there is zero risk of hydrolicking the engine with such type of flushing - and I can't imagine who could be capable (let alone willing!) to give such assurance - I wouldn't even think of trying.

OTOH, what I would definitely consider in jdrakeford boots is to move the strainer upstream from the pump, hence enabling the adoption of the BodgeFlow system.
But I would actually do that regardless of the flush, because either I am totally missing some major reason for doing the opposite, or whoever designed his boat in that way was high on drug when he did.

 

[bb_aes]

I purchased a new RangerTugs R43 with twin Volvo D6 diesels. While the engines have closed loop cooling, I have read that the seawater heat exchangers and coolers can really get clogged up from saltwater. I am not sure why flushing systems are not built-in these days (nor even an available option), but I want something to not only flush when the boat will not be used for a week or more, but to also aide in easy winterizing. The D6 has 2" lines between the inlet seacock and the strainer (which is located on the engine). (D4 has 1-1/2" lines) I am not sure why anyone even mentioned a 2" ball valve, but what I am installing is a 2" x 3'4" x 2" brass reducing tee with 2" 316 stainless steel hose barbs on each side. This will be put in the line between the seacock and the engine strainer. On the 3/4" side I will install a 3/4" ball valve followed by a garden hose quick connect. In a prior post someone said they were using a "stepped" tee, which would reduce the diameter of the inlet hose and limit flow underway, which must be avoided. In my D6's the strainer is mounted on the engine and high up so there is no room to add an input to the lid. But even if there was room, I would be reluctant to alter the lid, as anything that might cause a crack or other failure underway would make me nervous. Especially since my lids are plastic (so can see inside). The brass tee will not limit flow to the engine when underway and the garden hose connection is both easy and secure. But I am concerned whether a 3/4" garden hose can supply enough water to keep the seawater impeller lubricated during idle with seacock closed or if it has to remain open. If has to be open, I will never be sure how much saltwater is being sucked in with the fresh water. More importantly, I would not want the seacock open when running antifreeze in to winterize as I want to insure only antifreeze would be in system. Another reason for a closed seacock would be the ability to winterize when the boat is on the hard (blocked up). I also have read that running garden hose pressure into the pump without engine running can blow out pump seals (if seacock is shut). So I would have an inline garden hose valve near the engine switch so I could turn them on (or shut them off) the water and engine simultaneously. Am I missing anything here? Any thoughts from readers?

 

[bb_aes]

I was thinking about this as well; the Volvo Penta V8 petrol engine in my previous boat had as standard a flushing set up; basically a T piece in the water inlet before the raw water pump. There's no reason why such a set up wouldn't work on the D4 ( and why it's not standard, heaven knows !). I'd have fitted one already but I just don't know the inlet hose size.

The D4 hose size is 1-1/2" and D6 is 2". I am installing a 2" x 3'4" x 2" brass reducing tee (with 2" stainless steel hose barbs) between the inlet seacock and engine strainer for both easy flushing and winterizing.