Help with Sea Water Cooling System on MD2030

[Bluefin]

Hi

I have a MD2030 which is one year old (350 hours)

I am having problems with the flow of water, ever since I took my boat up for antifouling.

When it was on the dry I cleaned the inlets at the bottom of the saildrive as best I could.

As soon as I put the boat in the water and started up the engine the water did not come out of the outlet immediately but only after a few minutes.

Now it seems that every time I am under sail the water flows back out of the system (and empties) and when I start up the engine again the water does not flow through again, but takes quite a bit of time. This did not happen in the past.

I have also noticed that if I run the engine at high revs the water will never start to flow. I have to let the engine run at idle speed for a few minutes and as the water starts to flow I can bring up the revs slowly and the water will continue to flow, but not at the rate it used to before I took the boat out of the water.

I cleaned the seawater filter and there were some small bits barnacles etc.., but this has not solved the problem.

Do I need to change the impeller?

Do I need to clean the system from the saildrive to the water filter? If so is this possible.

Sorry for such a long message, but I have tried to explain my problem in full.

Thanks for any help.

Edward

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[Guest]

sounds like your impelor is knacked, www.asap-supplies.com will sell you one for about £14 instead of £24 for a VP one, give em a bell they are very knowledgeable, undo the six screws on the front of the pump, take the cover off, pull the impellor off, it has a drive pin thro it which engages with a slot, carefully push the new one into place, make sure the lobes are pointing in the right direction, put some silicon grease on the lobes and put the cover back on. if there are bits missing from the old one they are in the intercooler section and it gets a bit more difficult, you have to drop the fresh water coolant and remove the rubber boot off the front of the intercooler, 2 jubille clips, but the prob is that if you replace the boot and dont get it right you will end up with seawater in the fresh water cooling system.
stu

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[Bluefin]

Hi Stu

Thanks for your quick reply. I had a spare impeller on board so I changed it as you suggested. In fact out of the 6 fins only 1 was left!!!!

It is now bringing up water like never before!!!

Is it normal for the impeller to wear out so much after only 365 hours?

I did not try to clear the heat exchanger as you suggested. Must this be done? Would the pieces not have passed out with the exhaust?

Thanks for your help once again.

Ed





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[dickh]

Yes, the impellor can wear out very quickly. It should be checked as a minimum on a yearly basis, removed & stored when the boat is laid up, and replaced if any of the vanes are missing or are cracked at the root.
In theory you should check the heat exchanger as suggested, but if you are getting a good flow of water and you are not over heating then you can probably leave it for now but keep an eye on and check it at the winter layup.

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I'd rather be sailing... /forums/images/icons/smile.gif

 

[Guest]

an average hr for the year is 150 so my guru carl tells me, they reckon you should change every year! so yes its done its time, the bits are pumped with the cooling water thru the cooling system and the first place they come to is the intercooler tubes and thats wher they stop. if everything is ok and no over heating perhaps you could chance leaving there till haul out time and then you can remove the boot and clean them out
stu

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[tome]

I'd be a bit worried about where the other 5 vanes are lurking, almost certainly at the heat exchanger awaiting some rough weather to stir them up into mischief just when you most need your engine.

Sorry, maybe I'm being pessimistic but I agree with those who counsel that you rebuild the knackered impellor on the saloon table and make sure you have all the bits.

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[Bluefin]

Looks like I will have to clean out the exchanger at some point in time or another so I may as well do it now.

I only have the manual which came with the engine and this does not explain much.

Is there some other service / repair manual which I can buy for this engine?

What exactly do I need to do to clean out the exchanger. Stu said that I could connect something wrongly and end up with sea water in the fresh water cooling system. I really do not want this to happen.

Thanks once again.

Edward




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[tome]

I have a Volvo 2030 DIY manual on board so I'll check this out and post if there's a procedure.

Regards
Tom

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[Heckler]

hiya again, if you follow the outlet from the pump, the top one, about 1" diam rubber pipe to the top right hand side of the engine, you will see a rubber boot about 2.5 " diam with a 1" ish connection coming off it at right angles, if i remember this right, there is a small hose clip holding this on and 2 hose clips on the 2.5" end, slacken all these off ( close the seacock and drain the antifreeze) take off the boot and you will see a circular array of small tubes, your bits will be in there, perhaps some of them half way in the tubes, clean these out, even go so far as to get a wooden dowel to ream them out, then replace the boot, perhaps even a new one if the old is perished at all, the important bit is to get the 2 big hose clips on the right place on the boot and the boot over the casting in the right place so that when the clips are tightened they grip the right places.
simple really but also i repeat, if the engine is not over heating you could leave until haulout
stu

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[tome]

Here's what the Volvo MD2030 Workshop Manual says:

Important Close the bottom valve before working on the cooling system!

1 Drain off the water in the sea and fresh water systems

2 Release the hose clips and remove the rubber muffs at the front and back of the heat exchanger. Pull out the insert.

3 Flush and clean the insert inside and out. Clean also the housing.
NOTE! Make sure that the rod does not damage the tubes.

4 Fit the insert in the heat exchanger. NOTE! Make sure that the insert is positioned correctly! Make sure the hole in the insert casing comes opposite the hole in the housing and that the vent hole comes upwards. The insert is marked with "UP".

Place the insert so that its extruding parts are equal at the front and back.

5 Fit the rubber muffs on the heat exchanger's front and back and tighten the hose clips. Connect the hose from the sea water pump and tighten the clip.

6 Fill up with refrigerant.

7 Open the bottom cock or cock on the S-drive and start the engine. Check that no leakage occurs.

Good luck
Regards
Tom

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