Volvo MD11C - blocked drain plug

[drawp]

During this year's lay-up, one of the drain plugs at the bottom of the engine block was plugged with the usual gritty, rusty crap and would not drain. Does anyone have any suggestions on a quick fix for this or is it a strip down job. Poking and scratching around with a bit of wire was not successful.

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[petersto]

Last year (after buying boat) I noticed that the back cylinder was far hotter than the forward one. I like you attempted to poke about until I was advised by someone on this site to take the manifold off and have a good look. Well worth it in my case water channel from back block to manifold completely blocked and manifold containing all sorts of debris. Water cocks had obviously not worked properly for some time. Fairly easy job with new gaskets and good tool set including torque wrench.

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[VicS]

I agree with what you have said about unblocking the water passages in the manifold, one passage is longer than the other and so seems to block more readily.

Unblocking the water ways in the blocks is another kettle of fish. If you can't get anywhere by poking around with piece of wire through the drain holes (after removing the cocks), and you probably won't, the next stage is removing the heads and having a go from the top. Having gone this far if the water ways are really bunged up then you may want to consider lifting the blocks off so that you can have a really good go at them. Ultimately the liners can be pressed out by a suitably equipped workshop and the blocks cleaned up properly.

I suggest you check the availability and price of gaskets etc before you start.

When removing the heads and blocks take care not to damage the oil feed pipes that come up though the blocks and heads to the rocker shafts. Make sure you mark the various bits an pieces so that you don't muddle them up. You will need a suitable piston ring clamp to enable the pistons to be fed up into the bores from below on reassembly (the nomal car type is only suitable for fitting the pistons in from the top) Theoretically different thicknesses of shims are available to fit beneath the blocks in order to adjust the compressions, you may want to think about that (we used the standard ones). Make sure sure you fit the head gaskets the right way up. If you get them wrong you'll block off one of the water passages (the voice of exprience).

Unless there are indications of overheating (and the temperature guage cannot be relied upon here). I would not go to all this trouble unless you enjoy that sort of thing.

PS this topic has been aired before. Try a search for md11c and you should find what I and others have said.

<hr width=100% size=1><font color=purple>Ne te confundant illegitimi.</font color=purple><P ID="edit"><FONT SIZE=-1>Edited by VicS on 03/11/2003 13:46 (server time).</FONT></P>

 

[petersto]

VicS
While we are talking mdIIc you seem to know your way around a penta mdIIc so can I pick your brains. During the annual winteriseing oil change my oil pressure switch started weeping oil for no apparent reason. Tried a slight tighten no good, took the switch off looks ok but no fibre washer. I will fit one this weekend and try it again. Any ideas?


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[spannerman]

The different thickness shims you mentioned are not to alter the compression, they are to obtain the correct piston deck height when at TDC, if you get it wrong the piston will hit the cylinder head with expensive results, so I would advise anyone removing the cylinders to have a good manual with them to calculate the correct piston height.

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[mdrifter]

Re: Volvo MD11C - oil pressure switch

This happened to me a few years ago whilst on holiday up West Coast. Can't remember how I spotted it initially but remember sticking mamade tin beneath to catch oil which I then fed back into the filler...The leak appeared to self-seal after a time and I replaced the switch at the usual outrageous Volvo spare costs since when it has never happened again...heard that this was not an unusual failure when I ordered up the replacement.

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[VicS]

Re: Oil pressure switch

I don't off hand remember much about this. I do remember that we had to change it once because oil started to leak through it! (I recently had a similar thing with the stop solenoid on the car.. diesel leaking this time of course). If the thread is parallel you would expect there to be a joint washer of some sort but not if the thread is tapered. So either try a washer, fibre, aluminium, soft copper or something else slightly compressible but not a O ring if the thread is parallel or some thread sealing compound or PTFE tape if its tapered. I'm sorry I don't remember which it is. The old one is still on board, I think, but that's 80 miles away.

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[VicS]

It's some years since really stripped the engine down so some of the details are getting a bit hazy. My recollection is that you have to measure and adjust the shims so that at TDC the pistons are a certain distance below the tops of the blocks. It means bolting every thing down to make the measurements then taking it all apart again to adjust and refit the heads. I thought it was more than just preventing the piston hitting the head. That would be easy to do. Last time this was on the forum somebody did make some useful suggestions which might be worth finding.

I would agree that access to a workshop manual is essential. Ours is on board 80 miles away so I'm working from memory.

We had to strip the whole thing down when a broken valve spring dropped a valve in the cylinder ... it was expensive and difficult to get parts even then. The cooling saga is more recent but still several years ago.

When the valve dropped we had to keep the engine running on one cylinder for some time because there was no wind and the tide was carting us towards the rocks north of Herm. It made a bit of a mess.

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[TheBoatman]

If you don't get the right shims you alter the compression ratio as well?

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[petersto]

Re: Oil pressure switch

vicS
Tried PTFE tape no good so I am going fot the fibre washer. Someone has since told me they sometimes get a hairline crack above the nut in the insulation that supports the electrical terminal. Thanks for the advice anyway.

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[drawp]

Gentlemen. Thanks for all the replies. I had a suspicion that you guys would come good. I've had the exhaust manifold off and its ports were pretty clear so I will have to dig deeper. One question. Where can I get hold of a workshop manual without breaking the bank.

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[maxxi]

If you are going to do any of the above, and invest the time & money, it will be more than worth your while addressing the main problem & not the symptom.

All the waterway blocking and build-up of rust and other accretions are caused by low temperature running with raw water cooling. Converting to fresh water cooling need not be expensive, and will transform the engine and give it almost eternal life. Faster warm-up, proper operating temperature 80-95 degreesC, free hot water, no build-up of crud or blocking of waterways, inhibited coolant, better fuel economy, no more head-off waterway clearing every other year at £90+ per gasket set! etc etc.

As regards a workshop manual, I could photocopy my much thumbed photocopy of a photocopy, if you PM your info.

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