Mysterious sea water leak

[volvopaul]

Oil cooler end cap , the oil coolers corrode , you can’t see the cooler much as it’s under the heat exchanger and super charger , the steering oil cooler is on the suction side before the sw pump so I doubt it’s that as engine would draw air and overheat .

strainer lids leak , possibly exhaust elbow corroded or underside of intercooler.

 

[SimonD]

Thanks for the suggestions. I'd hope that the engineer would be able to see water coming from any of these leakage points. My worry is that he doesn't see where it's coming from. We'll see.

One final question before he looks at it on Wednesday. If he can't see any leakage from the engine(s) is it possible that the bellows are leaking and would this account for the symptoms? If so, would he be able to see this? I ask because he replaced the bellows on both stern drives and, as I say, the starboard engine has had water collecting under it ever since. The port engine has only had water under it since I lifted the drives to the beach position to clean the props a few weeks ago. Could the bellows have been disturbed by this? If water is coming through this area, it would run into the sumps under the engines.

 

[SimonD]

Thanks again for all the suggestions. Just to finish this off, the engineer came out this morning and found leaks on both engines. The port engine exhaust is leaking from the hose on the elbow. The starboard engine is throwing out large quantities of water from the area of the oil cooler. It's likely that this is from the drain hose which seems very perished, but he's going to pressure test the cooler if it's not that.

The lessons learned are that separate faults can occur in different places for no reason - just coincidence. Second, sometimes problems have the most obvious causes. Third, if the drain hose on the oil cooler fails, the engine will pump huge amounts of water into the engine sump and it would be a while before this reached the bilge and set off the alarm/pump. I'm thinking a float switch in each sump with an alarm might be prudent.

 

[Portofino]

A oil cooler fail = catastrophic engine fail if water enters the sump in any volume .
Best practice is ask around / internet search etc and timely arrange to change out parts rather than wait for fail .
With the Volvo KAD series and derivatives
List is not exhaustive....Black pipes , oil cooler , exhaust elbow , the horn , aftercooler box +++++ much more .
The professionals on here know , theses engines keep the wolf from the door

 

[BruceK]

A oil cooler fail = catastrophic engine fail if water enters the sump in any volume .
Best practice is ask around / internet search etc and timely arrange to change out parts rather than wait for fail .
With the Volvo KAD series and derivatives
List is not exhaustive....Black pipes , oil cooler , exhaust elbow , the horn , aftercooler box +++++ much more .
The professionals on here know , theses engines keep the wolf from the door

By sump I am pretty sure the OP meant engine bay bilge sump. And I completely disagree on your synopsis of KADs. They are one engine that thankfully are relatively simple to maintain. Yours has so many bells and whistle and squeaking flashy bits to make you sweat and hawk over it's hardly any wonder you've become a bit of an Eeyore and pedantic about every nuance of your engines when really they should be almost fit, forget and enjoy.

 

[SimonD]

By sump I am pretty sure the OP meant engine bay bilge sump.

Quite right; that's what I meant. Apologies for the misunderstanding.

Looking at the (non-exhaustive) list of parts that could fail, it might be best if I never started the engines again! It's true that bits can fail in a catastrophic way and I guess this provides customers for boat warranty providers. However, routine inspections of the condition of hoses etc. is enough for me. Certainly in this case, doing so would have saved me a lot of angst.

 

[Portofino]

@BruceK I have not got any VP KAD series or derivatives!
When I did ( first mobo after Yanmar 1GM s in sail boats ) I was a bit horrified by the complexity and poor quality of the components and general in my view preventable maintenance if stuff was better engineered.
eg like removing the strainer , a plastic cap and threaded thing to inadvertently drench the alternator.
Rusty pulleys = black belt disease , leaky water pump shaft .air leaks .Rusty and clogged elbows , rusty horn edge , loom insulation disintegration, every bolt or screw rusting .
Then theres all the VP woes on here .Ok even if you mentally give a bit or a lot stat wise because of the numbers out there the issues are for ever repeating eh “won’t rev above [ insert your rpm ] ,or “ Supercharger [ insert your problem ] “
” throttle pots “ + Trim pumps etc etc .
Just to be clear the above is excluding the actual outdrive ......lets not go there .Iam just writing about the bit inside the boat not the ally bits dangling in salt water .

Current machines MAN , my 2 nd mobo .....bolts / screws and the rest of the components don’t seem to rust , eg the belt pulleys are made of a metal that’s stable in salt air , alternator never gets wet , the pipe age is metal and bolted together, wether water or air = no leaks and the past 5 years have been refreshingly uneventful.....no parts except annual service consumables have been used ........in fact it’s predictably pretty boring compared to living with a VP KAD .

I know you are hands on and quite rightly proud of your own DIY ing , trouble shooting , diagnostics and spannering but not all are as enthusiastic about this kind of stuff and you may be atypically de sensitised to the huge effort required running aged KAD series + what ever outdrive they are attached .

Realise I,ll get flamed for this but I just say it ( pass on experience) as I see it .

If I was to go back down in size to a 30 odd ftr sports boat I would go the outboard route rather than tackle another VP outdrive outfit .Do my research first ....take a good look at them under the hood speak to techs etc .

 

[BruceK]

Porto

It's not what you say but how it's delivered. It's always on a downer. Hence Eeyore. Owners get filled with dread and depression after reading one of your rants on the engine. Now where as everything you say is grounded in truth the fact that these engines are still going strong 30 years after they were built in a huge number of boats is testament enough that what you are saying is heavily loaded. And the fact that they are doing so demonstrates that their problems are neither insurmountable nor particularly taxing. The fact that with a modicum of nous your average spanner spinner can keep them going just peachy but if yours go it's time to call in the consulting engineers. The KAD is easily serviced and rebuilt. Never forget it is an essentially cheap and cheerful replacement for the petrol V8 and competing at that level. Comparing them to yours is rather like telling your Mondeo owner that his car is shite because it's not Bentley. Or is that why this was brought up?

 

[Mr Googler]

Comparing them to yours is rather like telling your Mondeo owner that his car is shite because it's not Bentley.

Brilliant ???

 

[Portofino]

Bruce I don’t ,t buy into that , feel like you have missed the point ....my mention of a Yanmar 1GM was to illustrate reliability and build quality can be done at a low price .In other words I do not think there is a linear hierarchy with the cost and materials / engineering .
My geny Yanmar engine has a stain steel exhaust elbow , all the bolts still have paint on them , where it’s scratched off ( white ) they are grey not rusty .Its pulley is grey metal too .
Kubobta is another small marine engine well engineered.

Remember I,am not talking about the oily bits inside ....indeed Volvo do great piston rings , cranks , valves etc ...your point they don’t wear out .
Its the bits bolted on to the block and the execution of the design that lets them down going forwards .

So why ?
Well as you say they have such a grip on the market maybe it’s deliberate to not go down the longevity of the bolt on parts / bits in order to max out on the after sales and spares revenue .Sort of total marketing ploy kind of thing .

Others ( marine engine players ) do have obviously after sales networks but it’s more of a support ethos rather than a competing income stream from head office .

Otherwise Yanmar would have chosen a cast metal exhaust manifold over a stainless steel once only jobbie .

VP could build better engineered bolt on bits with the KAD and D series but they didn't,/ don’t

 

[BruceK]

You missed the point though. The KADs were engineered to compete against the petrol V8 and to my knowlege were the first to do so. That's compete on a power, weight and price point. The bolt on parts that need replacing are exhaust elbows, dirt cheap at 200 -300 quid, raw water pumps at the same, turbos' which can be serviced again at about 200-300 or replaced at ~twice that. These are not expensive or particularly taxing to replace in the world of diesel engines. I would agree that Volvo locking down Ogura in the root charger is a bit of a downer but even in a car a root charger is going to cost damn near the same. Yet when all is said and done there are huge numbers of these engines still out there. I got to be honest Porto, what ever you want to say about them it's an amazingly successful series and a testament to Volvo for producing such an engine at the price point they did.