3.0 typical crack area?

[HopinImFloatin]

ive got a friend with a new project boat on his hands. He just got it unsiezed and running but now is finding what he says looks like water in the oil. The boat sat for 3 years uncovered so rainwater may not be totally out of the question but sounds like a cracked block. He says that he didnt see any external cracks in the block or maniofold and i realize that doesnt mean its not cracked internally. He wants to change the oil and filter and run it to see if the oil level rises and the oil becomes milky again but the starter solenoid puked also. Is there any typical places to look on these blocks where they may normally crack so he may check that first before purchasing a starter for a motor that is junk?

 

[thumpar]

Re: 3.0 typical crack area?

How did he get it running if the starter is bad? I would suggest a leak down test.

 

[HopinImFloatin]

Re: 3.0 typical crack area?

he had it running twice but then wouldnt restart, badly corroded solenoid. Was just wondering if there were any typical crack spots that he may have missed before he continues.

 

[Don S]

Re: 3.0 typical crack area?

To see if there is a cracked block, disconnect the water hose going to the exhaust manifold and plug it. Then disconnect the water inlet hose from the thermostat housing. Drain the block of water and pressurize the block. Should hold around 15 psi with no problem.

 

[HopinImFloatin]

Re: 3.0 typical crack area?

To see if there is a cracked block, disconnect the water hose going to the exhaust manifold and plug it. Then disconnect the water inlet hose from the thermostat housing. Drain the block of water and pressurize the block. Should hold around 15 psi with no problem.

easy enough, thanks

 

[HopinImFloatin]

Re: 3.0 typical crack area?

ok, he pulled the exhaust manifold, filled the coolant jacket with brake clean and in the morning the exhaust was full of the brake clean( this was after he ran the motor and found water pouring into 2 cyls.). So we know the manifold is no good. There was lots of water mixed in the oil now. We made a pressure test rig for the block and so far has been holding 15 psi for the last half hour or so. So 2 more questions. (1) can a cracked exhaust manifold let lots of water in the crank case past the rings and (2) should the block be pressure tested warm also or is the cold test good enough?

 

[sti1471]

Re: 3.0 typical crack area?

Check for a blown head gasket. I am currently in the process of replacing mine out and it is not too hard. This will also let you see the cylinder walls as well as the cylinders themselves and let you know if the motor is even fixable. It could be a crack on the head surface, block surface etc..

A big cracking area for the 3.0L is right under the exhaust manifold right above the 2 freeze plugs on the outside of the block. During my head gasket change, I used a wire brush to clean the engine off so I can paint it. While I was using a wire brush I started removing epoxy putty. I removed more and noticed that the last owner cracked the block there and filed it with Putty and painted it black making it 100% un-noticeable. lucky for me it cracked on the outside of the block and not the inside as I don't have water in my oil. So I drilled the ends of the crack to prevent further cracking, and re-puttied it and it is fine.

If a 3.0L is going to crack, it will be under the exhaust manifold above the freeze plugs.

 

[bonzoscott]

Re: 3.0 typical crack area?

I think you need to look for a replacement motor. Water in the oil is typically cracked block. Water in the cylinder is typically faulty exhaust. Sounds like this motor has both, and a long road to recovery.

 

[HopinImFloatin]

Re: 3.0 typical crack area?

even though it pressure tests ok? finally took off the gauge after about 3 1/2 hours with no pressure loss

 

[bonzoscott]

Re: 3.0 typical crack area?

If Pressure test ok, next change oil and move on to compression test. Try and determine if bad head gasket. If all is ok, try and locate new exhaust.

 

[pastorjoes]

Re: 3.0 typical crack area?

IMPORTANT: First determine location of water in engine. This information can be of
great help when trying to determine where the water came from and how it got into
the engine. The three most common problems are ?water on top of pistons, water in
crankcase oil or water in crankcase oil and on top of pistons.?
The first step, after locating water, is to remove all the water from the engine by removing
all spark plugs and pumping cylinders out by cranking engine over. Next change oil and filter.
Now, start engine and see if problem can be duplicated. If problem can be duplicated, there
is probably a mechanical problem. If the problem cannot be duplicated, the problem is either
an operator error or a problem that exists only under certain environmental conditions.
If water is contained to cylinder(s) only, it is usually entering through the intake system,
exhaust system or head gasket.
If the water is contained to crankcase only, it is usually caused by a cracked or porous block,
a flooded bilge or condensation.
If the water is located in both the cylinder(s) and the crankcase, it is usually caused by water
in the cylinders getting past the rings and valves or complete submersion.
Check for rust in the intake manifold or exhaust manifolds. Rust in these areas will show that
if the water entered these areas.
If water is contained to cylinder(s) only, it is usually entering through the intake system,
exhaust system or head gasket.

 

[pastorjoes]

Re: 3.0 typical crack area?

[Did compression test 165 3 cyl 90 in the last cyl did leak down test and found bad rings, I want to know,,,, if the block holds pressure cold (15 lbs for 3+ hours)three is the block good or does it need to be warmed up and retested

 

[thumpar]

Re: 3.0 typical crack area?

Are you sure it is bad rings? How did you come to that conclusion?

 

[pastorjoes]

Re: 3.0 typical crack area?

Are you sure it is bad rings? How did you come to that conclusion?

leak down test. after determining it wasn't the valves I pulled the piston with low compression and two rings were unmovable when I tried to free them they broke,
Back to the question at hand if we put 15 lbs of pressure in the block and it doesn't lose pressure after 3hrs is the block good, I don't want to rebuild a cracked block

 

[thumpar]

Re: 3.0 typical crack area?

I understand a leakdown test but are you sure it was the rings and not a crack in that cylinder? Water doesn't get into the oil from bad rings.

 

[pastorjoes]

Re: 3.0 typical crack area?

I understand a leakdown test but are you sure it was the rings and not a crack in that cylinder? Water doesn't get into the oil from bad rings.

that's why I asked I pressurized the block with 15 lbs for 3hr with no leak down as Don S said
I did find that the manifold was cracked and allowing water into the cyl are you saying that water cant get by the rings
Merc says If the water is located in both the cylinder(s) and the crankcase, it is usually caused by water
in the cylinders getting past the rings and valves or complete submersion.

 

[sti1471]

Re: 3.0 typical crack area?

doing a leak down test is a good start. now that you have the head totally removed, pull the rest of the pistons. With the pistons out of the engine, get a light and inspect the engine top to bottom 100% sometimes you don't find a crack as it is so small that only magnafluxing can find it. however if there is not a crack visible to the eye, and you found a leak in the exhaust manifold to show where the water was coming from, I would install new rings and assemble it back up. Without magnafluxing, there is really no way to ever be sure that the block is crack free. You will just have to decide if you want to roll the dice and rebuild it or not.

doing a pressure test of 15 lb. does not say if the engine is good or not. If the crack is internal, then it will hold 15 lb. all day as the block is holding the air in from getting out, but it does not mean there is not an internal crack. Just remove the pistons and inspect it top to bottom and make your best judgment on if you feel comfortable moving forward with the rebuild.

 

[pastorjoes]

Re: 3.0 typical crack area?

doing a leak down test is a good start. now that you have the head totally removed, pull the rest of the pistons. With the pistons out of the engine, get a light and inspect the engine top to bottom 100% sometimes you don't find a crack as it is so small that only magnafluxing can find it. however if there is not a crack visible to the eye, and you found a leak in the exhaust manifold to show where the water was coming from, I would install new rings and assemble it back up. Without magnafluxing, there is really no way to ever be sure that the block is crack free. You will just have to decide if you want to roll the dice and rebuild it or not.

doing a pressure test of 15 lb. does not say if the engine is good or not. If the crack is internal, then it will hold 15 lb. all day as the block is holding the air in from getting out, but it does not mean there is not an internal crack. Just remove the pistons and inspect it top to bottom and make your best judgment on if you feel comfortable moving forward with the rebuild.

If there is an internal crack wouldn't it leak into the crankcase and out the oil stick or valve cover? If there is a crack it will lose preasure no matter where it is, Again my question if it holds pressure cold will it hold warm

 

[fishrdan]

Re: 3.0 typical crack area?

A leaky manifold allowing water into the pistons can let water into the crankcase, I had this issue earlier in the year, manifold was cracked by the center exhaust runner and I was getting a bit of water into the oil.

If the block held 15PSI for 3 hours, you're good to go, the water jacket isn't cracked.

 

[aerobat]

Re: 3.0 typical crack area?

doing a pressure test of 15 lb. does not say if the engine is good or not. If the crack is internal, then it will hold 15 lb. all day as the block is holding the air in from getting out, but it does not mean there is not an internal crack.

BS my friend. an external crack will leave the air just out and an internal crack will leave the air into the crankcase , the same way water goes into the oil- in any case it would loose pressure. thats why we maka pressure testing at all.

Again my question if it holds pressure cold will it hold warm

basicly yes. you use 15 lb of air to "force" tiny cracks to open and simulate with this a warmed up engine and expanding small cracks.

when it holds 15 lb for hours i would without any fear rebuild this block because you can strongly assume its not cracked.