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volvo penta injector blow by


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I started to smell some exhaust in the boat.  When I hold my hand over one of the injectors I feel pulsing air.  I assume that this is exhaust blow by and means that the injector is not completely seated.  On the side of the injector there is a shiny black coating that looks much like a vinyl product (e.g., liquid electrical tape).  I am not sure if this was some kind of "fix" that was applied by a previous owner or varnished oil/fuel?  There is almost no fuel that is leaking or bleeding.  I think that I can see a small bubble at the seat of the injector but a paper towel doesn't even get damp really.

Not sure what the fix is for this.  I saw an online video where someone removed the supply/return line and then put a small pipe over the injector and tapped it to reseat it.  Any advice on the best approach?

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On these old Volvo Pentas they use a copper sleeve, the injector sits in this & supposedly seals at the bottom. 
They're quite known for blow-by. 

The sleeves are still readily available, but you need a special tool to remove & install them. It was no longer (easily) available last time I looked. Nor could I find any local engine rebuilders that had it either. 
 

My solution in the end was to use an injector cutter tool to very carefully clean up the bottom of the injector sleeve. (use lots of grease) I followed this up with a with a disc of fine grit sand paper glued onto the end of a dowel. Use plenty of grease & go slowly and clean it out often. 
Once as clean as you can get it then refit the injector with a the thinnest copper washer you can get. 

This cured the blow by on my Penta 2001 & has been good for another 5 years so far. 

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I've had some luck backing off and retorquing the hold down nut... To "spec" of course ;)  Bits of carbon get pushed under there and not really much you can do without pulling the head once it starts leaking bad.  I pulled the head and shipped it off for rebuild on mine.. just under a boat buck if I recall and has been good since then.  Also.. pretty sure coolant is in the mix here so if for some ungodly reason you tried to pull a sleeve make sure the coolant is drained. 

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It appears to be a 2003 with plenty of info on google re this area. It appears to be wet around the area, like diesel is leaking and possibly combustion gases? When running the engine, backlight the injector and see what is being emitted, give the engine a rev and you should see/hear an increase in smoke and noise if it is combustion gas. Diesel leaking will typically be a drip, if it a mist then you may have bigger issues with the hp pipe or swagged end,

If it is just fuel leaking then try tightening the injector high pressure line nut, 17mm from memory. if it is combustion gases then as others have offered you will need to pull that injector and check the seating area. Clean as best you can and refit. If combustion gas has been leaking for any period of time there will be carbon build up on the injector seating area so this will need to be fixed prior to expecting a long term seal. Failing this cure then new injector tube is needed.

Is it a raw or fresh water cooled engine, does it have a heat exchanger?

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6 hours ago, Crazy Horse said:

It appears to be a 2003 with plenty of info on google re this area. It appears to be wet around the area, like diesel is leaking and possibly combustion gases? When running the engine, backlight the injector and see what is being emitted, give the engine a rev and you should see/hear an increase in smoke and noise if it is combustion gas. Diesel leaking will typically be a drip, if it a mist then you may have bigger issues with the hp pipe or swagged end,

If it is just fuel leaking then try tightening the injector high pressure line nut, 17mm from memory. if it is combustion gases then as others have offered you will need to pull that injector and check the seating area. Clean as best you can and refit. If combustion gas has been leaking for any period of time there will be carbon build up on the injector seating area so this will need to be fixed prior to expecting a long term seal. Failing this cure then new injector tube is needed.

Is it a raw or fresh water cooled engine, does it have a heat exchanger?

The engine is a raw water 2003.

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As has been said above, you can't do any more without now determining if you have a leak at the high pressure injection pipe (and they're usually quite obvious, as this is very high pressure) or pulling the injector to look underneath. 
 

Most likely its the seating area being dirty, if you end up having to take it off its a fairly easy job on these engines, no belts or chains, valves are pushrod actuated. 
I would try the copper washer first. Realistically these engine are 30 years old now, so you have to decide how much you want to spend on it. I'm not spending anything more outside of standard servicing on my 2001 & when it dies then its time for an upgrade. 

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  • 2 weeks later...

The shop manual indicates that there is an o-ring that goes around the injector but I don't see a part number and when I have looked up the sleeves online the sleeve is not referenced as a sleeve kit (some are) so I am not sure whether the sleeves come with an o-ring for the injector.  Has anyone sourced the o-ring and have an idea about a part number or size? 

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On 9/25/2021 at 5:02 PM, gkny said:

I started to smell some exhaust in the boat.  When I hold my hand over one of the injectors I feel pulsing air.  I assume that this is exhaust blow by and means that the injector is not completely seated.  On the side of the injector there is a shiny black coating that looks much like a vinyl product (e.g., liquid electrical tape).  I am not sure if this was some kind of "fix" that was applied by a previous owner or varnished oil/fuel?  There is almost no fuel that is leaking or bleeding.  I think that I can see a small bubble at the seat of the injector but a paper towel doesn't even get damp really.

Not sure what the fix is for this.  I saw an online video where someone removed the supply/return line and then put a small pipe over the injector and tapped it to reseat it.  Any advice on the best approach?

IMG_0478.JPG

Remove the injectors and send them off for service 

they will return with fresh seals and clean tips 

the classic  way to ruin a Diesel engine is with fouled injectors 

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As MiddayGun said, there is a special cutter to resurface the sealing surfaces on the insert without the need to remove/replace the copper sleeve.  I don't know where to find one, the old mechanic I used to fix this same problem (2003T engine) was in Mexico and had lots of weird old diesel stuff.  Maybe look for a mechanic as old as me?

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