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Hello all
I am new to this forum but have followed it before registering. I have a 2000 Larson Volvo Penta 5.7 gsi, that i recently overheated. Hot enough that the exhaust boots started to melt. I am a TN boater in fresh water.
I have had replaced the impeller, exhuast boots, riser gaskets. Now the boat will start up and run fine until you shut it off. Then it wont turn over. Take the spark plug out and i have water come out. Mechanic say head gasket and/or heads, but probably not a cracked block, and there is no sign of water in the oil. I am not sure if exhaust gaskets were changed or not (would it matter?). If it was a cracked block would there be water in the oil?
Or is the fact of no water in oil a good indication of head gasket/ heads?
Thanks
Sounds like water is leaking from head gaskets into the combustion chambers(CC).
With the CC full of water as the piston cranks upward approaching the firing stroke it is hydraulically locking.
I saw a 454 Vovo Penta literally break the aluminum starter drive housing.
I would close off cooling water supply. Remove the spark plugs. Pull the coil wire or pull overboard safety key,and crank it over several times and push out the water.
spray in some oil and crank it over some more,spray in more oil. Reinstall spark plugs.
Anyway the heads will need to come off and inspect.
You will need to determine what caused the overheat (like bad water pump) ;
because when it overheated it ,the heads could have warped, headgaskets blew,etc.
May be even worse.
I saw an overheat to a MAN Diesel,Repair was $85,000.
The hottest part of an engine is the exhaust manifold and the cylinder head.
Both can warp if overheated but since the head is not constant thickness, it warps much more easily than the exhaust manifold which is constant thickness.
my guess is the head is warped and since it is Fresh Water Cooled, the coolant is pressurized and leaks past the gap between the head gasket and the warped cylinder head. This fills the affected cylinder(s) with coolant when it is shut off.
You can blow the water out thru the plug holes and refire the engine but it will do the same thing again once you shut down. you can also allow high pressure combustion gasses to flow into the water jacket and blow the water out the overflow past the pressure cap.
don't run it! you could do much more damage to the engine. Save it from further corrosion by pulling plugs and putting oil in each cylinder and slowly crank over. Drain coolant out of block too.
There should have been an engine over temp alarm somewhere along the way...........
You'll have to pull heads to inspect anyway. New gaskets are an automatic, the previous poster was correct to get the cylinders clear of water quickly and fog them
Volvo had a service bulletin on that very problem a few years ago. There was a problem with the gaskets between the manifolds and the risers. I had the same problem and replacing the gaskets with the re-designed gaskets solved the problem.
Here is the Service Bulletin:
Quote:
During our routine audit processes, we have noted a potential for water entering the engine through the exhaust following an overheat condition. This can be traced at times to the loss of proper torque of the high-rise exhaust elbow. The expansion and contraction during and following an overheat condition can cause distortion to the gasket and prevent proper sealing.
It is our recommendation that when servicing an engine that has been overheated, the high-rise exhaust elbow gasket(s) should be replaced with gasket P/N 3863191 (V-6 & V-8). The following procedure supersedes the procedures that are outlined in the workshop manual under “High-Rise Exhaust Elbow Replacement.” 50347
Information for replacing the gasket are provided in the Installation Instructions entitled “Exhaust Riser Gasket, V-6 and V-8” (PN 7742588).
NOTE! When replacing this gasket, be sure to follow the directions exactly as described in the Installation Instructions.
There is no connection between cracked block and water in oil. However, an engine that hot may have sustained other damage which is not readily apparent. Chevy heads do crack. Disassembly is the first step.
Tear the heads off and bring them to a machine shop.....I bet they are cracked, if your lucky it's just head gaskets but my guess is cracked heads, I see it a lot.
I agree with carbo. Blocks that FREEZE from water in the cylinders crack at the bottom where the oil pan is. Blocks that crack from overheating crack where the hot areas are, which is away from the oil. A cracked exhaust port in a head will leak water into the engine when its shut off. A crack in the combustion chamber, where pressures are 2000 psi, will blow all the coolant out of the engine. In any case, excessive heat can damage the rings and warp stuff. Disassembly is the only test.
I have a 2 year old Volvo Penta 5.0GXi engine that is now catastrophically failed. You got it. Water in the cylinders after an overheat. Dealer botched properly troubleshooting the overheat condition on several occassions. The details are in another thread (I forget which one). Been duking it out with the dealerships insurance company.
While I am convinced Volvo Penta is the best I/O engine on the market, I will never buy one again because Volvo reps just cared about trying to screw me and protect the dealer.
What good is owning a great engine when the dealer can't properly diagnose and fix problems with the engine. Then you go to the manufacturer for relief and the Manufacturer slides it up your back door.
Tear the heads off and bring them to a machine shop.....I bet they are cracked, if your lucky it's just head gaskets but my guess is cracked heads, I see it a lot.
Before you go pulling off the heads....check the risers/gaskets...cooling water can enter the cylinders if they're leaking or the risers are cracked.....you can run the boat and remove the risers...look down into the manifolds and see it there is water laying around the exhaust ports....good luck...Mick
Before you go pulling off the heads....check the risers/gaskets...cooling water can enter the cylinders if they're leaking or the risers are cracked.....you can run the boat and remove the risers...look down into the manifolds and see it there is water laying around the exhaust ports....good luck...Mick
2 times I have had hydrolocked 2 seperate mercruiser 496's. Both times fault was manifolds/risers. Is the water isolated to one side of the block? If so I would pull the manifold and risers on that side, visually inspect and pressure test.
I'm with Slickster and meii. go with the easiest and less expensive first. Manifolds and risers go bad and do let water go back into the cylinder's. When you find water, is it the same cylinder or a different one each time? If it is the same one chances are it's the head. If it varies (but on the same side) it is probably a riser or manifold. If you pull them the dealer should be able to pressure test them. If they can't you can make a plug from a piece of wood and bolt it down. Pressurize the manifold and see if it leaks into the exhaust portion.
You never did say what caused the overheat in the first place. Was it the impeller or something else?
All you have to do is perform a compression test for each cylinder. If you have a cracked head or bad head gasket this wil show up as poor compression in that cylinder. The compression will be listed in a service manual. Look for even compression on all cylinders.
Slats, the split jury is pretty close but you can narrow your diagnosis a little more. Riser / gasket failures usually first appear in the center cylinders directly under the riser, Cylinders # 3,5,2,4. Is water in all of the holes? just One? You can pull the water hose off the bottom of the manifold and run the engine for a few seconds, maybe 10 or so. Then pull the plugs and bar it over. If water is still found rip the heads off. No water found then its an exhaust issue. You can trouble shoot it with a screw driver and plug wrench in minutes. Oh yeah, kink off the loose hose when running the engine to insure good internal pressure of the engine. And don't worry you wont fry your new boots. Just pay attention.
__________________ Baitkiller= Accredited Marine Surveyor
Bait fear me, fish just laugh.....
The little Dutch boy was just buying time...
Thanks for all the responses. The overheating came from the impeller going out, and i did not notice the temp gauge. The alarm didnt go off either. The smell got our attention, we shut it off and black smoke from the boots came out when we opened the hatch.
The mechanic said there is water coming out of the cylinders (plural, but did not say if both sides). Riser gaskets were put on after the overheat, but nothing about risers or manifolds was mentioned. From what i read on here, i am probably looking at heads. Thanks
I talked with mechanic this morning. Water is in both sides and mainly front and back cylinders. he said he would inspect exhaust first and continue all the way to heads until he finds problem. I am hoping for it to be gaskets but am not holding my breath.
Thanks
David
water in cylinders 
