Best chemicals for flushing a raw water cooled Volvo Penta?

[saltyrob]

Hi,

The yard where boat stored in winter is not keen on running engines in cradles and exhaust outlet only just above water so securing bucket isn,t really practical.So would this plan be ok.Warm engine up afloat ,remove impeller,thermostat and anode,disconnect exhaust hose from silence/water lock and run hose from exhaust elbow to bucket ,connect hose with in line electric pump to water inlet on side of engine and place free end in bucket.Fill bucket with warm solution of Fernox or Rydlyme and circulate around engine.Sorry if this is labouring a point, but am worried that I could somehow damage engine and belt tightening with regard to boat budget taking place at present

Many thanks

Rob

 

[SimonD]

The yard where boat stored in winter is not keen on running engines in cradles and exhaust outlet only just above water so securing bucket isn,t really practical.So would this plan be ok.Warm engine up afloat ,remove impeller,thermostat and anode,disconnect exhaust hose from silence/water lock and run hose from exhaust elbow to bucket ,connect hose with in line electric pump to water inlet on side of engine and place free end in bucket.Fill bucket with warm solution of Fernox or Rydlyme and circulate around engine.Sorry if this is labouring a point, but am worried that I could somehow damage engine and belt tightening with regard to boat budget taking place at present

Sounds like a good plan. However, it might be easier if you leave the exhaust hose alone. As you're taking the thermostat out (and assuming the layout is similar to the VP2002) just disconnect the copper pipe that runs from the thermostat housing to the exhaust elbow at the elbow end. Then take out the thermostat and turn the housing through 180 degrees. That gives you an nice bit of pipe sticking out the front of the engine. Bit of hose on this into your bucket.

At the other end, I'd leave the pump impeller in place (that doesn't need flushing) and disconnect the outlet pipe from the pump. Connect your electric pump to this pipe (might need lengthening).

I don't see anyway you can damage the engine, so courage mon brave!

 

[vyv_cox]

Yes, sounds OK to me. So long as there is no possibility that water could go up the exhaust into the engine there's not much that can go wrong. Making the Fernox solution up with hot water would help, remembering that chemical reactions more or less double in rate for every 10 degrees C increase.

 

[mikejakes]

Thanks for all of your replies. I have opted to try Rydlyme Marine based no the feedback across the forums on YBW plus it's sold at a Volvo dealer close to where the boat is. The approach that I originally envisaged was to use a central heating pump to circulate the Rydlyme solution for four hours (connecting to raw water inlet and having made up a Heath Robinson adaptor of sorts for the exhaust and supplied by a header tank in circuit). However, when I went to pick up the Rydlyme, an engineer was staffing the shop and he advised me to drain the block, add the the solution via the strainer with the motor running the leave in place for several days if I suspect that fouling is heavy (as indeed I do), even though the manufacturers suggests a four hour maximum. He said that this is the approach that all of the engineers his company uses on the VP range in these circumstances and is very successful, so I've shelved the idea of pumping the solution and have followed his advice (fingers crossed).

Re. draining the block, I removed the drain tap as loosening didn't allow any water past, but the holes in the base weren't blocked. I didn't remove the other half, but stuffed a bit of wire coathanger into the hole to try to clear any blockage, Unfortunately this didn't work and I couldn't move the wire around too much as there's a bulkead close by which prevents me from getting complete access to the drain. Instead. I drained most of the block via the anode hole under the alternator, so although not perfect I've removed most of the seawater: I'm hoping that the Rydlyme solution will clear the blockage for me...

 

[SimonD]

How much Rydlyme do we need to flush the 2002? It needs to be diluted 1:1 so it's half the capacity of the engine (only, as it's raw water cooled). The freshwater version is about 5l but I can't find the corresponding capacity of the raw water version.

 

[mattnj]

How much Rydlyme do we need to flush the 2002? It needs to be diluted 1:1 so it's half the capacity of the engine (only, as it's raw water cooled). The freshwater version is about 5l but I can't find the corresponding capacity of the raw water version.

5L includes a decent size heat exchanger, plumbing, pump etc, having had the FW cooled one completely apart, i would guess, the raw water version is about 3.5 L

 

[SimonD]

Thanks for that - sounds about right.

 

[Red Admiral]

Lots of very helpful advice but are you absolutely sure that the overheating is the result of silt build up? In my experience of a raw water cooled 2002 the problem was the scaling and partial blockage of the small holes in the copper tube which passes through the head from forrard to aft and connects finally with the exhaust mixer. The small bleed holes in this tube provide the only cooling water to the head and block. In my own case I bought a new tube, drilled out the holes (I think to 5mm) for good measure and have had no overheating since.
To get the tube out you remove the small hose from the raw water pump where it goes into the head and, at the back, the small hose from the head to the exhaust mixer. You can then, with a suitable drift, drive out the tube from the front of the engine.

 

[mikejakes]

Red Admiral> I had an engineer look at the engine after I'd checked the raw water pump, inlet and thermostat, and he found the sludge, plus he said that he checked the water distribution pipe in the head by pushing a long screwdriver up it.

However, having thought about it since I put the Rydlyme solution into the motor, I'm leaning towards removing the pipe from the head to double-check as well when I drain it, as although the pipe may be clear longitudinally, the small holes might be blocked and I guess this wouldn't be apparent just from sticking a screwdriver up there.

What diameter drift will I need to remove the distribution pipe from the head, and am I likely to damage it during the process?

Thanks
Mike

 

[SimonD]

Sounds like a good plan. However, it might be easier if you leave the exhaust hose alone. As you're taking the thermostat out (and assuming the layout is similar to the VP2002) just disconnect the copper pipe that runs from the thermostat housing to the exhaust elbow at the elbow end. Then take out the thermostat and turn the housing through 180 degrees. That gives you an nice bit of pipe sticking out the front of the engine. Bit of hose on this into your bucket.

I've just tried my own method and it has a serious shortcoming. On the 2002, there's a bypass pipe at the back of the engine that runs from the head/block into the exhaust elbow. I started the pump up and water came through this into the exhaust elbow. Arrgh. I'm planning to have another go after removing and bunging up the pipe outlet.

Apologies for duff advice.

 

[ianat182]

As no-one has answered the last part of the OP's query.
May i suggest you find a Vetus filter, or a similar-to one as I have (Vetus very expensive) I cannot read the name on mine but it is about 5" diameter and a fine filter within;there is no 'O'ring seal in the lid or body on mine and Vaseline or grease makes it easier to open and seal when closed. It is mounted just about 6" above waterlevel .
It is almost too good a filter, as the 1mm dia holes stop every thing passing through, and so can become clogged quickly if in a weedy area. Any increases in temperature make this your first check.
I now have a regular check of the filter every time I come back from a sail, clean it of all debris, as part of the shutting down procedures, greaser, battery , keys, isolator switch,VHF and GPS, and bilges.
If memory serves the Vetus one was about £40.

ianat182

 

[mikejakes]

I've just tried my own method and it has a serious shortcoming. On the 2002, there's a bypass pipe at the back of the engine that runs from the head/block into the exhaust elbow. I started the pump up and water came through this into the exhaust elbow. Arrgh. I'm planning to have another go after removing and bunging up the pipe outlet.

Apologies for duff advice.

It's the same setup on the VP2003, and as I didn't want to take a hacksaw to the expensive looking pipe to insert some form of bypass valve for flushing and don't have the facilities at home for machining proper adaptors, I decided to go down the exhaust hose adaptor route. I got some 45mm bore truck radiator hose from a local supplier and made a 22mm adaptor from a domestic plumbing bulkhead adaptor put into the nozzle end of a cut-down mastic tube: I used about the end 50mm or so (enough to get a couple of pipe clips onto) and cut off the threaded spigot that is used to screw the nozzle to, drilling it to take the bulkhead adaptor. This was persuaded up the end of a 6 inch piece of the 45mm hose and clamped in.

Ultimately though I didn't use this rig: when I collected the Rydlyme from the VP dealership in Port Solent, the engineer manning the counter said that I when he and his colleagues use Rydlyme, they drain the water jacket (important and often overlooked step apparently) add the Rydlyme then leave if for a few days before flushing. This is significantly longer than the manufacturers instructions (who suggets 4 hours), but he assured me that it has been fine on the many engines that he has used it on. As the boat is usually on a swinging mooring, I didn't want to spend the money to leave it in a marina for a week so that I could use the electric pump and flushing rig, so I followed the engineers advice last weekend and having drained the system, I left the Rydlyme in place statically for a week with the boat still on the mooring.

I returned to the boat yesterday and flushed the system by starting the engine and running it for two hours. When I initially started it up, the cleaning solution was pumped out of the exhaust followed by what looked like a load of light brown then light grey sediment. After about 10 minutes once the engine was warm, I ran it at around 2500 - 2800 rpm for 2 hours (it revs under no load to about 3500 rpm). Throughout this time, the engine seemed to be pumping decreasing amounts of light grey sediment out, although as the water flow from the exhaust superficially seems to have improved (which could of course just be wishful thinking), this could conceivably have been simple aeration. In any case, after two hours of hard running (albeit under no load), the engine showed no sign of overheating, so I hope that the problem has been resolved. My current thinking is that I will flush the block with Rydlyme using the pumped rig as an integral part of the winterisation process: once the engine is flushed, I can then fill the block with an antifreeze solution using the same technique.

I didn't remove the cooling water distribution pipe from the cylinder head as I wanted to check the effectiveness of the Rydlyme: if the engine shows signs of overheating again, this is the next step. I asked the above engineer about the modification to this pipe, and he said that it was simply to make the holes bigger, advice consistent with that elsewhere on this forum. However, he said that if enlarging the holes, great care must be taken to completely deburr the holes as limescale and other deposits will very readily take hold around any burrs that are left on the inside of the distribution pipe following the enlargement of the holes, causing the pipe to block more quickly than normal.

ianat182> I looked at a bulkhead-mounted Vetus filter whilst in Port Solent (it was about £80) but the hose is a different diameter to what's in place, so I will have to get an appropriate hose adaptor machined up once I've located somewhere to mount it (the comparitively small engine bay)

 

[Red Admiral]

There is always the possibility of damage using a drift - best to make up a shouldered drift with larger diameter the outside diam. of tube, smaller diameter the internal diam. of tube. Can't remember the actual dmensions (it was about seven years ago I did job) but size easily determined by removing the small front hose from raw water pump to cylinder head and measuring end of tube.

Best practice would be to buy a new tube from your friendly Volvo dealer (part number for your engine 84060-0) so you wouldn't be stuck even if tube is damaged when being removed. Also makes exact sizing of drift easy.

Final thought; I tried all the business about removing crud with little success as far as stopping overheating but my engine has not overheated at all after fitting new transfer tube with enlarged bleed holes. I believe such modifications are acceptable in prolonging the life of a twenty year old engine.

 

[jaylo264]

Adding to this thread:
I'm about to remove that cooling tube from my VP2002 raw water head, as the rubber seal on the (front?) end is now very perished following my engineer pickling the head in some jungle juice he uses whien refurbishing it; the seal seems to have a lip behing the copper lip of the tube. My holes were very blocked, not now though, but I think I have to get the tube out anyway.

The thing is, Red Admiral , how do you know the part number of the tube-?- I am hoping that whatever source you have for part i d will also have a cooling system diagram better than that in my VP owners workshop manual, which could have been better drawn by my 12 year old.

And did anyone actually remove this tube, and IS it drifted out from the front or rear ?

Many thanks,

jaylo264

 

[VicS]

parts lists and diagrams at http://www.marinepartseurope.com/en/default.aspx may well help. Ceratinly give you the parts numbers

 

[mikejakes]

I did...

@jaylo264: during the process of winterising my 2003 I discovered that the head gasket had gone, in all probablility due to the overheating that happened last year. I also noticed that the water jacket was still dry in the area of the water jacket drain on the block in spite of repeated flushing with noxious chemicals (although there was water in the area of the engine anode).

As a result, I decided to remove the tube from my cylinder head to try to get to the bottom of the issue. The pipe drifts out from the front towards the back and you'll have to remove the metal pipe between the head and the exhaust elbow to provide an exit on the rear of the motor and also the feed pipe on the front (below & to the right of the water temp sensor). I used a straight drift and succeeded in trashing the (brass?) pipe in the extraction process, so suspect that the shouldered drift might have helped but the reduced diameter section would have to extend to the whole length of the pipe to avoid the bending along it's length that I experienced. I also found that I had to drift the pipe out for it's entire length, it didn't release part way out. Interestingly though, the holes in the pipe weren't obstructed, so any blockage must be within the water gallery somewhere (still to be identified).

I've sourced a replacement pipe from Mototech at Port Solent for about ninety quid and have enlarged the holes out to 6mm from the standard 3mm but have yet to reinstall as the head still has still to be reconditioned, etc. The engineer at Mototech had a good point about hole enlargement though, which is to ensure that *absolutely all* burrs are removed from the inside so as not to give any future deposits a foothold.

As the boat is still in a bazillion bits (and my end March relaunch looks increasingly like a naive pipe dream), I've yet to establish whether this will fix the problem.

 

[jonrarit]

@jaylo264: Interestingly though, the holes in the pipe weren't obstructed, so any blockage must be within the water gallery somewhere ................I've sourced a replacement pipe and have enlarged the holes out to 6mm from the standard

An old thread I know but lots of volvo penta engines still out there including mine. Suspecting my overheating under load was being caused by the blocked water distribution pipe, I too popped mine out & enlarged the holes however the cause was in fact there is a very specific orientation of the pipe when inserted into the engine to ensure the holes line up with the channels inside the engine and my pipe was not correctly turned hence not enough circulation hence overheating.

Easy and cheap fix .... words you don't normally associate with Volvo Penta marine engines I know

JR

PS - Guilty m'lord ...... I was the last person to have the pipe out so my fault entirely but if my error helps others avoid then thats got to be good.

 

[NealB]

Apologies for resurrecting a 'well-old'VP 2003 thread, but ......... is there a simple method to make sure that the water distribution pipe is inserted in the, precisely correct, and "very specific orientation", as mentioned in post #37?

 

[VicS]

Apologies for resurrecting a 'well-old'VP 2003 thread, but ......... is there a simple method to make sure that the water distribution pipe is inserted in the, precisely correct, and "very specific orientation", as mentioned in post #37?

Do you have the workshop manual ? There is a diagram in there that shows the correct orientation

.

 

[NealB]

Thanks VicS.

The only diagram I've got is this one:


It's probably me being thick, but I'm not sure how to interpret that.

It shows that the distribution pipe has six holes, so that's two per cylinder.

Four of those holes look to be in a straight line (let's call them the the 1st, 3rd, 4th and 6th, starting from either end), and two (the 2nd and 5th) are slightly offset.

So I'm not sure, precisely, what the 'clock face' is telling me.

If anyone can explain it to this numbskull, he would be most grateful!