MD 7 B water in oil

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shell

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my volvo md 7b seems to be suffering from water in the oil, grey coloured thickened oil in the sump and condensation in the rocker box.
I have read the posts on syphoning but the engine is fitted with an anti-syphoning device, also running the engine hard does not seem to improve the situation. She starts well and idles fine.
Is it possible that water can come in any other way, possibly through corroded cooling channels. I have also seen a post stating that the MD7B does not have an engine electrode, how is corrosion kept under control? Perhaps I could remove the head and then remove the block to inspect. Is this easily done in situ?

Any suggestions?

Thanks......
 
it can get via water pump if shaft seals leak and the telltale holes get blocked easier to check than taking head off

correct no anode but unlikely to get water in through corrosion of block

also check that a syphon valve is not choked up take it off and boil in water to get salt crud out
gaskets are expensive on this engine so taking apart just for a look not best idea
 
When it happened to mine it was accompanied by steam from the exhaust and was caused by a blown head gasket. The water was leaking across from a cooling channel to one of the cylinders.
I replaced the head gasket and had the head skimmed but the problem returned within a couple of months.
Best solution was to completely block the offending water channel with 'plastic steel'. That lasted until I changed the engine for a Beta but I think it would have solved the problem permanently. There was no sign of overheating and no apparent hotspots. It is relatively easy to remove the head in situ, I did it at anchor in less than an hour. Gaskets are expensive...
 
These engines have cooling channels very close to the cylinders. After time it is not uncommon to find corrosion or cracking of the cylinder head and /or block that can only be corrected by skimming. If it has cracked, welding and skimming is possible. If corroded badly you can machine the head and block to the thickness of the cylinder head gasket and replace with 2 gaskets to restore the correct compression ratio. Gaskets are indeed expensive but not as expensive as a new engine.
 
You probably had corrosion on the face of the block itself as well. Even if you didn't skimming the head increases the compression ratio and makes the problem more prone to happen again. See full answer on my other post...
 
Does your engine have brass drain plugs on the blocks and do you have wet liners ?????

There is an oddball occurence with some Volvo engines and allthough a typical example existed in a photograph in PBO last year the writer made no reference.

I have seen several of the wet liner volvo engines mysteriously develope water leaks to the sump whiich was difficult to identify the source...What can happen is that some sort of electolytic action takes place between the drain plug and liner which results in pitting so deep it breaks into the liner below the piston so is invisible unless the block is lifted.

Usually there is a slight shadow on the liner wall above the drain plug level indicating water is destoying the lubrication of the rings in this position.

To prevent this I recomend owners turn the wet liners about 45 degrees on every occassion they have a head off, say every 5 years..this spreads the pitting.

You should consider changing both liners if you find one has pitted right through.

If you can find the article in PBO you will see what looks like a drilled hole in the lower liner...Why did the contributor NOT comment ??


John
 
First suspect the water pump...

if the set up is the same as the older Volvos, which I think it is, then, as Scottie says, the seals on the waterpump shaft can fail and if the drain hole blocks as it well may the upshot is water in the oil.

I fancy this is the most common cause - and easy to fix, for much less than the cost of a gasket set!
 
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