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Water in cylinder 1 Volvo Penta V6

danwils

New member
New to the forum. I have a Mustang 32 foot boat with twin Volvo Penta V6 4.3 ltr engines. I had recently had the boat at the marina for the yearly anti foul. after relaunching I decided to test the new props and took both engines up to 3000 rpm It all went well for about 1 minute when the Starboard engine started to miss and splutter, I pulled the throttles back down slowly. and the Starboard engine stopped. I tried to start it with no success. it sounded like the starter wasn't working just a click, tried a few more times with same result. Arrived back at my private jetty when my friend told me the bilge pump was spewing water out of the bilge.Tuned the Port engine off to discover the bilge half full of water and the Starboard engine was flooded with salt water. I emptied the bilge and decided to investigate the Starboard engine, it wouldn't turn over. it hydrollicked I then pulled the spark plugs out and water pressure in number 1 cylinder blew the plug out of my fingers. I then pulled all the other plugs with no water at all, then turned the engine over until no water came out of the no 1 cylinder. I then squirted water displacement oil into all cylinders , removed the exhaust and riser from that bank and checked the gaskets ,no problems, all good no water leakage there. I put number 1 spark plug back in to see if the engine would turn over, and it did with no lockup at all and no water in number 1.
Can anyone give me any idea as to what the problem could be. I don't like to put all the plugs back in in case it bends a rod or something worse.
Sorry for the long post, just wanted to give you all the full picture.
 
Hi Capt. Bob,
I have done a compression test and all cylinders are between 198 & 206psi . both engines are raw water cooled. with fresh water flush system
 
do you boat in fresh or salt water? how many hours on the engines? Does it freeze where you live? IFSO, Were engines winterized?
Look for a crack at the elbow to manifold joint or a bad elbow ( corroded wall between water jacket and exhaust path).
 
In Australia the weather doesn't get cold enough to winterize. We use boats all year round. It is used in salt water only, the engines have around 200 hrs.on each. The exhaust and riser manifolds were replaced 12 months ago, and are in top condition. I checked the exhaust to riser gasket, it looks perfect, no sign of cracks in the water jackets. It just seems strange to me that the Starboard engine got this problem at the same time the Port engine blew the raw water pressure hose.
I am stumped. Looks like I pull the head and look for water ingress there. Thanks Captain Bob.
 
4.3 old cyl heads small.jpg4.3 reman cyl head 2 small.jpg4.3 new cyl heads installed.jpg
I had the same problem on my 4.3 (at the time it was about 28 years old and had approx 1,000 hrs on it, I tested the exhaust manifolds and they were fine, it turned out to be a leaky head gasket right between a cyl and one of the water passages. I had a bad overheat about 3 seasons before the head gasket leaked (actually had the same problem on both sides, #1 and #2 cyls). My compression test results were pretty normal but I tested for bubbles in the cooling water (replace the hoses that go from the thermostat housing to the manifolds with clear hose) warm it up good with it in the water (you want the stat open) and you could see it then. Took it all apart and it was obvious, likely overheat damage. The heads had cracks in the center cyl exhaust valve seat area so I wound up replacing both and putting it back together with new gaskets and cyl head bolts. Still running well 5 years later.
 
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Hi LOUC,
Thanks for the advice, That is my next attempt. I have done lots of work on Auto engines but have not done anything on a marine engine. All the electronics have slowed me down a bit, but I am getting there. All I require are about 20 photos to see where everything goes, plus a few additional tools. I have downloaded a
Volvo Penta workshop manual for all the correct toque sequences, so here goes nothing. Will keep all notified when it all happens.
 
Any questions ask away.
Tips:
I had a hard time getting the intake off due to the baked on OE gaskets (unlike the Vortec gaskets the pre-vortec ones never leak but they also don't want to come off!)....I used two padded screwdrivers (with electrical tape) to shove in the gap where the RTV is in the front and rear of the block to pry it loose. It was not coming off at all, till I did that as a last resort, it didn't damage the sealing surfaces due to padding the screwdriver with electrical tape.
To remove the head bolts, due to raw water cooling you will probably have to use an impact gun, I did and I tried an 18" 1/2" drive ratchet before that, with all my strength, it was not budging them. The impact did the trick.
get a thread chaser and clean out the cyl head bolt holes in the block they will have crud in the bottom of some of them due to raw water cooling that will prevent the head bolts from getting an accurate torque reading. Buy new head bolts, same reason the old ones will be corroded, and throw off your torque reading.
Organize the parts so you don't lose stuff, take pix, make notes, etc. Clean, clean clean. Bolt holes, and all sealing surfaces on the block and heads must be immaculately clean. Use Fel-Pro marine head gaskets if you can get em. They seal very well. I used Permatex Aviation sealer on the threads for head bolts and intake bolts. No leaks, so that's what works.
 
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Hi Louc,
Took the port head off, expecting to see a crack in the gasket, or at least a sign of water leaking through but to no avail. The gasket was in perfect shape with no sign of water intrusion. Checked the inlet manifold for any leakage signs, but no sign of water leakage, and the same problem , I am sure whoever installed the gasket must have used super glue or something like it. Couldn't see any obvious signs of cracks or leakage. Next step is to send the head and inlet manifold off to the engineer for crack testing. Haven't yet removed the valves to check for cracks in the valve seats, (next project).Will keep you informed.
 
With the head gaskets the problem on mine was not obvious till I took them off and there was a slit in the ring that goes around each cylinder that was allowing water in. If your intake had sealer on it it is possible that someone was in there before. Is this a pre Vortec (12 bolts on intake manifold) or a Vortec (8 bolts on the intake manifold)? The Vortecs were definitely more prone to leaks at the water ports of the intake manifold. However these leaks were more likely to put water in the cam valley & motor oil not so much in a cylinder. Not saying it's not possible though. This problem was solved with revised gaskets. If it is a Vortec keep in mind that the torque specs for the intake manifold are much lower than those of the pre Vortec; those got 30-35 ft lbs, the Vortec gets like 11-15 ft lbs IIRC. Tbe head bolt tightening procedure is also different between these 2 styles of the same engine. See what the inspection of the intake & cyl head shows. On mine I had to replace the heads but was able to resurface the intake. Sometimes with salt water use the heads can rust through behind the exhaust valve seat but I doubt that in only 200 hrs. Mine were getting thin after 15 seasons worth & were cracked from an overheat. Reman units were approx $275 USD each. Gasket set $100 and head bolts $100. So parts cost of the whole repair was about $750-800 USD.
 
Hi louc,
I still haven't had time to remove the valves at this stage, I have to borrow or buy a valve spring compressor at our local parts shop. I can;t see any obvious signs of cracks at all , the inlet manifold looks in good shape and had the new type of gaskets fitted so it looks like the last owner had some problem. about to send heads to amachine shop for crack test, so I will also send intake manifold as well. I am hoping it is not a crack in the block, but doubt it very much. Have to turn the pistons over and check to see if any cracks stand out. fingers crossed. It is a slow process as I don't have a lot of time to do this. will keep all informed. Thanks.
 
I had a bad overheat on mine in 2013 which I think damaged the head gaskets and they failed about 3 seasons later. The cyl heads both had cracks in the center cylinders exhaust valve seat areas but the block was fine. It is common when a Chevy small block had a bad overheat the heads may crack but the block survives. 5 seasons after the repair there is still no water in cyls or motor oil. I’m interested to what the cause was in your case. I’m thinking a crack or rusted through area in the cyl head.
 
I have not had an overheat problem, I think mine is lack of use as I have had a few bad months, however I am still waiting for the valve spring compression tool to arrive from the supplier, I will then be able to check for a crack. To be truthful I am hoping that is the problem, I don't want a crack in the block as that is a major
for me as I will have to go to the marina and organize a crane to lift and replace the engine, and that is big dollars for us here. Will keep you posted.
 
I have my doubts there is anything wrong with that engine. sounds like you blew a hose, spewed water on to starbert engine which shut down causing backflow to #1 cyc.
( "discovered bilge half full of water" )
 
Hoping you are correct, just pulled the valves from the head exhaust valve seats on two ports showed a fair bit of rust but I am thinking that was due to the pull down letting water in. I will take precautions and send the head to be pressure tested as I am this far. Will keep you informed. If all OK I will reassemble and hope for the best.
 
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