VicS
Well-Known Member
ITYWF thats to do with positioning the tube nest so that the engine coolant flows around outside the tubes correctly. I dont think it has any bearing on the flow of seawater through the tubes.
End cap balooning on Volvo MD2010
- Thread starter LeonF
- Start date
ITYWF thats to do with positioning the tube nest so that the engine coolant flows around outside the tubes correctly. I dont think it has any bearing on the flow of seawater through the tubes.
LeonF
Well-Known Member
Vic there's a tiny hole, apparently, I never saw it but didn't know to look for it, on the upper side of the stack that needs to be kept clear, again not sure why, perhaps as you say to allow the coolant to flow smoothly. But as Vyv says, if that flow is impeded it could cause over pressure to work its way past the clips and into the raw water side, but all this is guesswork. I'll let you know the outcome once I've had a proper look, I didn't have time when I was down there as I needed to get ashore before I lost the tide.
VicS
Well-Known Member
Ah yes on the tube stack. I thought you meant an external bleed hole or vent on the heat exchanger body. Hence the confusion 'cos that would simply allow coolant to escape!
The workshop manual says
I imagine if the vent hole is only small it is just to allow any air to escape from the insert when the system is filled.
This is all on the engine coolant side of things which pressurizes when the engines heats up, the pressure is controlled by the pressure cap. Just like the radiator cap on a car cooling system.
The seawater side of things is quite separate . Water is simply pumped through the tubes by the seawater pump. Going in via the end cap at the front and out via the cap at the back and then into the exhaust elbow, or riser when fitted. There should not be much pressure on the seawater side unless there is some partial blockage. If the tubes are blocked the front cap will be pressurized. If the injection point into the exhaust is restricted both caps will be pressurised.
The symptoms you describe, namely the inlet cap pressurised, would suggest that the tubes are partly blocked, but you say they are not.
If they are not then you should look at the injection into the exhaust, as has been suggested
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LeonF
Well-Known Member
Thanks I will do.
Ruffles
Well-Known Member
Pretty standard problem with the high rise manifold. Internal corrosion reduces the water flow. As it is a gradual process you probably will not notice any reduced flow at the exhaust.
The first time it happened I tried cleaning out exhaust deposits with acid. Waste of time as the problem was corrosion in the water passage. When the engine stops the anti syphon valve will allow the water in the manifold to drop but it will not empty completely. So it always has some salt water in it. Which is why there is a drain on it.
I eventually proved to myself I had to buy a new one by taking it to RK marine and comparing new with old. Blowing through the water inlet indicated significant restriction in the old unit. Others of this forum have tried cleaning out the corrosion and ended up making a hole in it. Which, I guess, proves it was corroded.
Remember, you will need a new gasket if you put the old manifold back. New units come with a new gasket.
I now 'winterise' properly with antifreeze. PITA if you use the boat occasionally in Winter. But cast iron and salt water must have a limited life?
The first time it happened I tried cleaning out exhaust deposits with acid. Waste of time as the problem was corrosion in the water passage. When the engine stops the anti syphon valve will allow the water in the manifold to drop but it will not empty completely. So it always has some salt water in it. Which is why there is a drain on it.
I eventually proved to myself I had to buy a new one by taking it to RK marine and comparing new with old. Blowing through the water inlet indicated significant restriction in the old unit. Others of this forum have tried cleaning out the corrosion and ended up making a hole in it. Which, I guess, proves it was corroded.
Remember, you will need a new gasket if you put the old manifold back. New units come with a new gasket.
I now 'winterise' properly with antifreeze. PITA if you use the boat occasionally in Winter. But cast iron and salt water must have a limited life?
john_morris_uk
Well-Known Member
I've suffered from almost exactly the same symptoms with our Volvo 2040 with exactly the same high rise exhaust.
The problem was eventually tracked down to a coked up high ruse injection 'elbow'.
The small hole in the heat exchanger stack merely allows the coolant to fill the stack properly. Nothing to do with the problem the OP describes.
PS I did successfully clean out our high rise exhaust with brick cleaner (ie HCl?) and various other cleaners.
The problem was eventually tracked down to a coked up high ruse injection 'elbow'.
The small hole in the heat exchanger stack merely allows the coolant to fill the stack properly. Nothing to do with the problem the OP describes.
PS I did successfully clean out our high rise exhaust with brick cleaner (ie HCl?) and various other cleaners.
LeonF
Well-Known Member
Dismantled the end caps and stack, all clear. Exhaust elbow is high rise, usually fitted to the larger models, but Volspec were helpful and said this was probably because it's on the waterline, even though I also have an anti-syphon fitting. Elbow is lightly coked, but there was a large loose piece of coke, which I reckon might have been the problem as it presented at high revs, suggesting this might have caused it to get wedged. I currently have the riser in a bucket with some foam sink unblocker, but does anyone have a suggestion for something better just to give it a good clean ? John and others have suggested B&Q brick cleaner the kind with HCl, but I couldn't find any on their shelf and it's been suggested that it might corrode the metal.
jerrytug
N/A
Get physical Leon, Screwfix drain unblockers, like the old pantomine chimney sweep rods. Electric drill, flexible drive, rotating wire brush. Abrasive scrapey things on a bit of string, pull back and forth. That sort of thing.
vyv_cox
Well-Known Member
HCl in the strength you can buy will not corrode your exhaust elbow. It is available from many sources: in the past fortnight I have seen 5 litre bottles of it in a small ironmongers in the local town and in a street market stall in the same place. Almost any building supplier will have it as brick cleaner or patio cleaner.
sailorman
Well-Known Member
A slight point of order
Patio cleaner will be a fungicide rather than hydrochloric acid
vyv_cox
Well-Known Member
http://www.diy.com/nav/build/buildi..._source=RatingsAndReviews&utm_content=Default
Click on HEALTH AND safety
sailorman
Well-Known Member
You left the Brick bit out first time
LeonF
Well-Known Member
Sailorman I believe some of the brick and patio cleaners do have HCl. Caustic soda has also been suggested.
vyv_cox
Well-Known Member
You left the Brick bit out first time
??? I clearly said 'brick cleaner or patio cleaner'.
LeonF
Well-Known Member
Spirits of salts, 30%HCL, 500ml off the shelf at Robert Dyas, £2.00. Reckon the poster who said it's not so much the coke as the waterways, especially on a high rise, was right. Had it in a bucket last night but the rust spots were bubbling alarmingly so didn't have the nerve to leave it for more than a couple of hours. Now have some trying to work it's way thru the innards. Might also try caustic soda. Huge range of products cheap at Dyas.
LeonF
Well-Known Member
Thought I'd update. Just before lift out in November, I refitted the high rise elbow after soaking and prodding for a week or so, the problem was worse, both caps now ballooning and reduced water flow. Have finally returned to the problem, now on shore, removed the elbow. A good blow had my cheeks ballooning so at least I know it's def where the problem lies. Had the inspection caps off (No 10 allen key) very coked. This is the odd bit, assuming the water flows around the outer channel and the exhaust round the inner, you'd expect the outer to be corroded but it also seems to be coked which leads me to suspect corrosion between the two waterways. I may have a last go at cleaning it, especially as a new one is £440 ! Or do I risk a normal exhaust elbow ? Where would the anti-syphon be on the exhaust ? My exhaust leads into a Vetus style plastic water trap, then exits into the cockpit locker where it sits in many serpentine coil before exiting the boat on the side just above the waterline. The cost difference is tempting me not to fit a high rise elbow, but am I inviting trouble ?
Cantata
Well-Known Member
Leon old chap, this made me blink. I bought a new one for my MD2020 in March 2012, it cost £129.60 plus VAT from Keypart. It's part number V861906 on the invoice and it says it's the part for the MD2010/20/30/40. I just looked on Keypart's website, under the MD2010 parts, and it's now £162 inc VAT. So the quote you got sounds unreliable, or extortionate.
LeonF
Well-Known Member
Cantata is yours the same as this one ? They aren't fitted as standard to the 2010. I'll have a look at Keypart
http://www.volvopentashop.com/Volsp...eDieselEngines/7746410/7746410_25/7746410_056
Tranona
Well-Known Member
The anti syphon goes between the raw water pump and the entry into the heat exchanger min 40cm above the waterline. Not sure why you have a "serpentine coil" of hose in the cockpit locker. It just needs a loop above the waterline (min 45cm - but as high as possible) before it drops to the outlet. Also check that there is a 30cm length of hose from the exhaust outlet to the water trap.
Cantata
Well-Known Member
Er oops no, it's this one one this page - scroll down -
http://www.keypart.com/volvo-penta/diesel-engine/md2010b/19941998
Sorry, I hadn't read this thread again for a while and I remember the high riser stuff now. But, as the previous post says, can you instead use a standard elbow and fit a riser in the hose?