Signs of impending engine failure

[Montemar]

Assuming that your engine has been correctly serviced and not abused is it fair to say that it will go on forever or that sooner or later something major will go wrong.
If so would there be any warning signs and what might they be?

 

[Bandit]

Give us a clue what engine?

One of the most important things with a service is an experienced and trained engineer who knows the model he is working on well having a good look all over the engine toom at engines, gearboxes, stern seals etc.

 

[Montemar]

TAMD41B or TAMD61. Basically the older, six cylinder VP diesels.

 

[stelican]

Assuming that your engine has been correctly serviced and not abused is it fair to say that it will go on forever or that sooner or later something major will go wrong.
If so would there be any warning signs and what might they be?

High coolant temperature or low oil pressure

 

[kashurst]

Oil consumption starts to noticeably increase, topping up on a regular basis, not as powerful as it used to be - intake tracts getting coked up, gungy inlet valves.
very noticeable blue tinge to exhaust smoke on a very sunny day - I find most diesel engine smoke looks a bit blue on a dull afternoon. However if it is a Ford Mermaid it's absolutely fine.
crankcase breathers blocking faster

Oil pressure at idle lower,cruise oil pressure lower. - check the engine manual for acceptable limits
Eventually oil pressure warning light will start to flicker at idle - by this stage its probably NOT the sensor, it's rebuild time. Our first boat started to do this when we sold it 16 years ago. It's still going - it does have a very easy life on a river though.

If you carry on further then you get a knocking noise at idle that reduces under load - big ends going. (my first car, you couldn't hear the knock at 90mph but it didn't last much longer after that experiment)

However a well maintained engine would take a long time to get to this point. Regular proper use and proper service etc will give long life. PS. I think marine turbos are a consumable.

 

[Portofino]

Not sure about looking too close at oil pressure .
I would check the “blow by “ - it may be called or referenced different.

What I mean is take off the oil filler cap on the rocker box and see if there’s any pressure at what ever various rpm s .

If there’s tons of oil spitting out and more so when revved up then the rings are shot - gas is escaping below and the air pressure coming out of the filler cap .

To fix this it’s gonna need new pistons / rings / liners at the minimum but you could carry on spending- while the heads off refurbish the head(s) , while its out of the boat new crank bearings etc .

 

[No Regrets]

It's either going to go bang due to a component failing due to metal fatigue, which is unusual these days, but most likely lose oil pressure and start to consume engine oil, and get harder and harder to start as the compression drops due to piston wear.

I suspect most old marine engines get cooked due to overheating though!? :ambivalence:

 

[mlines]

You are just thinking you seem to have money in your bank account at last and your boating expenses are under control = impending engine failure

 

[Bandit]

I am not familiar with the 61's,

The 40 series, 32, 40, 41, 42, 43 , 44 and 300.
Oil coolers corrosion
Overheating due to calcified build ups.
Water injection bends after turbochargers
Sumps on outdrive boats

 

[Montemar]

Thanks for your replies.
When doing a quick look around the engine compartment I found a bilge with water in it then saw the drain tap for the aftercooler sitting on a stringer. It was brass and had de-zincified and gone very soft. There were no obvious signs this had happened as it was seawater that had leaked. Eventually the bilge pump would have started up and given the game away. I was not aware there was an anode in the heat exchanger that would have prevented this, mine had completely dissolved. My manual did not mention them!
It pointed out the need for regular, thorough inspections.
Twice I have heard of problems with water injection bends so they go on the list but would the oil cooler corrosion be in the heat exchanger for the oil?

 

[Bandit]

It pointed out the need for regular, thorough inspections.
Twice I have heard of problems with water injection bends so they go on the list but would the oil cooler corrosion be in the heat exchanger for the oil?[/QUOTE]

Injection bends rust up and start to block up reducing the raw water cooling flow for the engine and causing hot spots in the rubber exhaust hose.

Oil cooler corrosion on the 40 series starts as a salt water drip which causes bi-metalic corrosion between the aluminium casting of the cooler housing and the brass end plate, eventually the oil which is under pressure forces out the rubber seal and it looses all of its oil. This is not good at WOT.

 

[Montemar]

Thanks, I suspect leaks of water or oil presage problems - nuff said.

 

[volvopaul]

Assuming that your engine has been correctly serviced and not abused is it fair to say that it will go on forever or that sooner or later something major will go wrong.
If so would there be any warning signs and what might they be?

If this is your engine get an oil sample taken .
If it poor starting . Low oil pressure when it’s hot, smoke from the crank case breather , these are all 41 series issues, your will always work hard in a Broom 33

 

[Montemar]

Thanks, so far so good as it shows none of your symptoms. I run them at 3500 rpm which gives me 15/16 knots which is just on the plane and I get about 1mpg (ouch).
Your survey was right.