Volvo penta 2003 help - rusty liquid coming out air intake silencer

[SailsFlying]

Hi,

I have a 1989 Volvo Penta 2003 fresh water cooled engine which has started doing this:

Air intake silencer leak <- had to link photo as image size too big.

No signs of blown headgasket under oil cap or in expansion tank. Engine starts easily and doesn't loose any coolant or oil, runs well as far as concerned.

This patch of rusty fluid only appears after a good few hours of engine use. It's not visibly coming out when running and not loads of it either in total at the end of the day. Most of that in the photo is what had been dripping out overnight into the bellhousing from the silencer drainage hole.

Could this just be condensation? Recently I've been adding marine 16 diesel additive, the correct amount specified if that would have any impact like this :s?

Any advice or opinions welcomed

 

[Freebee]

marine 16 would have no impact on this, if its water running out of a drain hole i would suggest that the designer knew this might happen, condensation and rusty because the inside of the silencer is rusty???

 

[vyv_cox]

Difficult to imagine condensation in a warm engine. It takes hours for one to cool inside the engine room and will probably be warmer than the rest of the boat for 12 hours. Looks more like a fine coolant leak, but if the inside of the silencer is so rusty, painting it will give you more information and will save it

 

[Snowgoose-1]

Is it definitely coming from the air cleaner hole ? Not from something dripping higher up ?

As mentioned, worth checking the innards of the air cleaner which would be conclusive.

 

[Pete7]

Is it definitely coming from the air cleaner hole ? Not from something dripping higher up ?

As mentioned, worth checking the innards of the air cleaner which would be conclusive.

Since this is likely to require destroying the pan as its pressed steel, perhaps replace with a K&N filter from their universal range.

Pete

 

[SailsFlying]

marine 16 would have no impact on this, if its water running out of a drain hole i would suggest that the designer knew this might happen, condensation and rusty because the inside of the silencer is rusty???

I cleaned the inside of the silencer by soaking it in diesel last year as it says to do this in the Volvo workshop manual. Its been a while since then so doubt it would be that out of nowhere.

There is rust in the intake manifold part of the head when you take the silencer off and look inside but the rest looks spotless under the rocker cover.

 

[SailsFlying]

Difficult to imagine condensation in a warm engine. It takes hours for one to cool inside the engine room and will probably be warmer than the rest of the boat for 12 hours. Looks more like a fine coolant leak, but if the inside of the silencer is so rusty, painting it will give you more information and will save it

A coolant leak is my main concern - I really don't want to have to take the head off to find out. In that area of the head there is a crank shaft breather hole which I have checked is clear. That's the only place I can imagine fluid to coming from as the area of the valves/under the rocker cover is clean as anything!

 

[SailsFlying]

Is it definitely coming from the air cleaner hole ? Not from something dripping higher up ?

As mentioned, worth checking the innards of the air cleaner which would be conclusive.

Yea it's definitely coming from the air intake silencer, when looking underneath it you can visibly see where it's coming out of it

 

[SailsFlying]

Since this is likely to require destroying the pan as its pressed steel, perhaps replace with a K&N filter from their universal range.

Pete

My next idea is to take the silencer off while running and see if I can see anything else happening inside the intake manifold.

I'll have a look at those K&N filters as its worth a shot for trial and error. I would think more clean air through one of those rather than a 30+ year old silencer has to be better for the engine too!

 

[QBhoy]

Hi. I’d say you’re taking water in from the exhaust side or a compromised interface seal somewhere.
Don’t suppose you’ve had a positive pressure of water to it without the engine running at some point ? Like a hose into the cooling system for running her when on the hard for example?
Failing that…it certainly looks like the rusty colour of water you’d see from a failed header or exhaust elbow, allowing water where it shouldn’t be. Only other thing that would cause that, would be if it’s being rotated or cranked in the wrong direction…meaning it wound actually pull water in from the exhaust side

 

[SailsFlying]

Hi. I’d say you’re taking water in from the exhaust side or a compromised interface seal somewhere.
Don’t suppose you’ve had a positive pressure of water to it without the engine running at some point ? Like a hose into the cooling system for running her when on the hard for example?
Failing that…it certainly looks like the rusty colour of water you’d see from a failed header or exhaust elbow, allowing water where it shouldn’t be. Only other thing that would cause that, would be if it’s being rotated or cranked in the wrong direction…meaning it wound actually pull water in from the exhaust side

I swapped out the exhaust elbow for a stainless steel one when we first bought the boat, I might try to tighten it up a bit more see what happens, failing that it's gotta come off to do the head anyway if it comes to it. From what I can remember I didn't actually check the head where the elbow mates to it to see if there was carbon build up inside there. The exhaust piping looks original to the boat too, it doesn't seem like its collapsed inside as there's good water flow etc.
The original elbow was pretty bad for carbon build up, maybe over time it forced water through the head gasket creating a channel and I'm only seeing the results of that now? I haven't had a hose pipe running water through it at any point nor cranked it in the wrong direction either.

Another thought is that it could be stuck rings creating lots of blow by? It's hard to figure out what the brown residue is as it doesn't smell like diesel and seems to have an oily consistency, it's definitely rusty. I haven't got the stomach to do a taste test yet!!

I'll be going out again soon hopefully so will wipe the rusty mess off and see what appears afterwards!

 

[Boater Sam]

I cleaned the inside of the silencer by soaking it in diesel last year as it says to do this in the Volvo workshop manual. Its been a while since then so doubt it would be that out of nowhere.

There is rust in the intake manifold part of the head when you take the silencer off and look inside but the rest looks spotless under the rocker cover.

Could this possibly be just residue from soaking it in diesel that has run out when it got warm?
Cleaning wire gauze by just soaking would leave a lot of oily muck in the gauze.
I think you have nothing to worry about.
If you eliminate all possible leaks and causes then this is what it is.

 

[Stemar]

My experience of those "air cleaners" is that they don't do much. I'd take it off, run the engine until the dribble should have started and see what happens.

I'm struggling to see where water could come from within the engine as, from memory, it's a crossflow job, so no connection between the inlet and exhaust manifolds, and the inlet manifold is all above the head gasket.

I can't help wondering if the source isn't a leaky water pipe above the air cleaner - or rainwater getting in somwhere.

 

[SailsFlying]

Could this possibly be just residue from soaking it in diesel that has run out when it got warm?
Cleaning wire gauze by just soaking would leave a lot of oily muck in the gauze.
I think you have nothing to worry about.
If you eliminate all possible leaks and causes then this is what it is.

Hopefully it is just that and I'm worrying too much and not sailing enough lol.

Randomly it's just started happening now, there's been no rusty residue for a long time since I cleaned the filter. :s

My experience of those "air cleaners" is that they don't do much. I'd take it off, run the engine until the dribble should have started and see what happens.

I'm struggling to see where water could come from within the engine as, from memory, it's a crossflow job, so no connection between the inlet and exhaust manifolds, and the inlet manifold is all above the head gasket.

I can't help wondering if the source isn't a leaky water pipe above the air cleaner - or rainwater getting in somwhere.

The inlet manifold is definitely above the head gasket - could it be possible that raw water is getting into the cylinder via dodgy head gasket then forced out past of the valves on the upstroke and out through of the inlet manifold?

The silencer appears to have drainage hole underneath and it's really obvious it's coming out of it, there seems to be a 'spray' going on too from it when you look at the bellhousing. The spray is new as it was previously just dripping out over time.

 

[scottie]

The drain hole may actually be a hangover from when the same air filter was originally used on the MD1 engine and had a breather hose fitted and on later engines had a plastic bung the inlet trumpet faced down and was self draining as I recall
taking the air filter off and leave it to drain whilst not using the engine may give a better idea of what is actually coming out
it would also give you a chance to look at exhaust
most boats can probably run without a filter short term but not wise long term
if you have antifreeze it would not normally be brown but worth checking header tank
the genuine filter costs is extreme to alternatives may be worth

 

[Stemar]

The drain hole may actually be a hangover from when the same air filter was originally used on the MD1 engine and had a breather hose fitted and on later engines had a plastic bung the inlet trumpet faced down and was self draining as I recall
taking the air filter off and leave it to drain whilst not using the engine may give a better idea of what is actually coming out
it would also give you a chance to look at exhaust
most boats can probably run without a filter short term but not wise long term
if you have antifreeze it would not normally be brown but worth checking header tank
the genuine filter costs is extreme to alternatives may be worth

They didn't seem to be available when mine disintegrated a few years ago, so I MacGyvered something out of a Tupperware thing that was the right diameter and a few washing up sponges. The engine didn't seem to notice the difference,