volvo 4.3l - water in oil

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  #1  
Old 07-09-07, 09:21 PM
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volvo 4.3l - water in oil

I need a suggestion----
I have a 21.5 Sunrunner with a Volvo 4.3L and a 290 dual prop leg.
Last winter it froze. I though that I got all the water out, but there was just enough to pop the frost plugs.
I pulled the top of the motor down, had the heads tested along with the intake and the manifold/risers.
After regasketing the whole thing and making sure that there was sealer on the head bolts, all seemed to be OK.
I ran it for 30 minutes on the hose and there was no water in the oil. I put it in the water and under idle, it was fine.
Once I got it under load for about 10 minutes, I took off one of the valve covers and the oil was all milky.
I thought that one of the water cross overs in the intake had let go, so I took it off and regasketed it.
Same result.
I have now ripped the whole motor down, had everything including the block checked with 50 pounds of air and magnafluxed.
I added new rings and bearings nad a new crank.
I put it all back together and thought that the situation was cured as there was no water presenting at low revs. As soon as I put it under load again, the top of the motor filled up with water.
The motor never got over 110 degrees and it is raw water cooled.

I am now at the point of throwing away all the old engine parts and starting again.
Anybody got any suggestions?

Thank You
 
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  #2  
Old 07-10-07, 06:15 AM
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A few things come to mind when reading your post. First: If I strictly read your issue - I would have to guess that you've got a cracked block/head that didn't show up during the magnaflux process. Everything seems to point in that direction. When the engine heats up and gets under pressure, the crack allows the water to leak into the system.

Second: On the other hand, the problem you describe could also be as simple as a warped deck/head surface that does the same thing (I assume you had both checked for straighteness during the machine work). Typically this doesn't happen unless you've experienced some serious overheating prior to the problem rearing it's ugly head.

Third: You sound as if you've some experience rebuilding engines - so I will assume your followed the correct torque sequence/specifications when putting the top of the engine back together. Those specs are critical in preventing leaks also.

I would guess that you're faced with three choices - take her all apart again and have the block/heads checked again by a different machine shop after explaining the situation clearly to them - then reassemble with all new gaskets, new head bolts if appropriate, and following the manufacturers specs to the letter. The easier, though spendier option is to toss the unit and buy a new or rebuilt engine to slip into place. The third option would be to have the existing engine rebuilt by a reputable shop that will guarantee their work - probably the mid range choice for cost. If it leaks after they do the rebuild - then it shouldn't have cost you anything and you can move to the new/rebuilt engine option.

Good luck - I know it can be extremely frustrating.
 
  #3  
Old 07-11-07, 03:33 AM
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One thing to consider that happened to me on my volvo penta inboard was the impeller shaft seal had failed and was leaking water back into the block...good luck, frustrating problems I know.
 
  #4  
Old 07-15-07, 08:34 AM
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Location: Savannah, Ga.
Posts: 38
From my experience, most of the time water in the oil is caused by a problem in the exhaust, either manifolds, risers, or bad or missing flapper valves in y-pipes that can let a rush of water into the engine when you come down off of plane quickly. Did you use the same exhaust components that you took off? Did you use RTV on the gaskets when you put it back together? I know the manufacturers mostly say not to use it, but that's because they don't think that we have the good sense to just use a very thin coat on both sides of the gasket so there isn't a lot of excess RTV squeezed out to clog the water passages.

Sounds like a frustrating deal. Good luck with it.
 
  #5  
Old 07-15-07, 09:17 AM
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Dan has a real good point, a lot of repairs are done without
looking into the exhaust. And as the shops are not able to mag them
many times they are presumed good. Freezing will crack them and they
are a lot thinner than the cylinder walls.
On the Volvo though we have had a lot of water intrusion due to
the riser gaskets alone. The mfg has changed the composition of
them recently.
It would probably be the best move at this point to check the
exhaust carefully or just swap it out.
I assume you are not getting any puddling of water in the cylinders
and that it runs fairly well, just gets the oil all milkshakey.
Sounds like exhaust.
 
  #6  
Old 07-16-07, 06:33 PM
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Join Date: May 2007
Location: VA
Posts: 16
BoatMech,

Of course anything is possible but I just don't see how cracked exhaust manifolds or bad riser gaskets will allow water to wind up in the oil that quickly. Any water entering the exhaust will wind up in the combustion chamber. If there is a lot of water entering it will hydrolock the engine. A little bit of water may still allow the engine to run but if it's sitting for a while it usually will cause a piston or valve to rust and seize. The only way for the water to wind up in the oil is if it is pushing past the rings or the valve guides. Since the engine just had a total rebuild this seems unlikely.

Bigguns, pull your spark plugs and look at the tips. If Normal plugs show a slight layer of soot. If you have water in the cylinders the plugs will usually show signs of rust or will be "waterblasted" perfectly clean. If you pull the manifolds you may see signs of rust at the bottom of the exhaust ports.
 
  #7  
Old 07-18-07, 09:00 PM
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Join Date: Jul 2007
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Unhappy Try this

Originally Posted by bigguns View Post
I need a suggestion----
I have a 21.5 Sunrunner with a Volvo 4.3L and a 290 dual prop leg.
Last winter it froze. I though that I got all the water out, but there was just enough to pop the frost plugs.
I pulled the top of the motor down, had the heads tested along with the intake and the manifold/risers.
After regasketing the whole thing and making sure that there was sealer on the head bolts, all seemed to be OK.
I ran it for 30 minutes on the hose and there was no water in the oil. I put it in the water and under idle, it was fine.
Once I got it under load for about 10 minutes, I took off one of the valve covers and the oil was all milky.
I thought that one of the water cross overs in the intake had let go, so I took it off and regasketed it.
Same result.
I have now ripped the whole motor down, had everything including the block checked with 50 pounds of air and magnafluxed.
I added new rings and bearings nad a new crank.
I put it all back together and thought that the situation was cured as there was no water presenting at low revs. As soon as I put it under load again, the top of the motor filled up with water.
The motor never got over 110 degrees and it is raw water cooled.

I am now at the point of throwing away all the old engine parts and starting again.
Anybody got any suggestions?

Thank You
I had the same thing a few years back and it was believe it or not the intake manifold.....the crack was visible just never thought to look there.

Good luck....BreakOutAnotherThousand Boat......
 
  #8  
Old 07-18-07, 09:05 PM
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Posts: 2
Try this!!!!!!

I had the same thing a few years back and it was believe it or not the intake manifold.....the crack was visible just never thought to look there.

Good luck....BreakOutAnotherThousand Boat.......
 
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