Chevy 350 - Water in oil

D

dl2525

Member
Joined
May 4, 2009
RO Number
31205
Messages
375
My buddy has water in his oil on a chevy 350. I checked the dipstick and it's painfully obvious. He just picked this boat up, so previous work by the owner is suspect.

Let me know if my thought process is correct for diagnosis -

Causes for water in oil -

1. Leaking riser joints
2. Leaking intake manifold gasket
3. Leaking head gasket
4. Oil cooler that is mixing due to a leak internally.
5. Cracked head/block

Here's what I would do...

1. Pull the plugs and turn the engine over with the key. Do you see water shoot out? Is it the center cylinders? If so, it's probably the riser gaskets.

2. Pull the risers and look at the surfaces. Do they look flat? No material missing or eroded on the mating surfaces? Do you see any rust traces down the manifold internally? If so, again the riser gasket may be leaking.

3. Pull the valve covers. Any milky fluid in the top end? Could be intake manifold gaskets.

4. You said compression numbers were all even? 170ish? That could be a sign that the head gasket is good, but a leak down test would be better (pressurizing the cooling end of the block). Sometimes this doesn't even show a bad gasket because the block needs to be hot.

5. Pressure test the oil cooler.

That was my recommendation. Am I missing anything? If the oil cooler is good and holding pressure, would you throw new riser gaskets and intake manfold gaskets on and water test the boat? If that doesn't fix it, then I'd assume the head gasket must be bad or the head is cracked? Pull the heads then, get them manufluxed unless you can visibly see a bad gasket, replace the gasket, and finally water test again?

Let me know.
 
Depending on how long the engine sat with this condition, BUT, water won't readily leak past the rings so you can generally eliminate the leaking riser gasket.

Oil cooler is raw water cooled and not likely to get in the block other than the water jacket...in raw water cooled engine.

Head gasket or cracked head/block if there's lots of water in the oil...or leak in intake manifold/gasket or not tightened down.

Is water/oil mixed (chocklately) indicating the engine has been run with contaminated oil?
 
quote:
Originally posted by jtybt15

Depending on how long the engine sat with this condition, BUT, water won't readily leak past the rings so you can generally eliminate the leaking riser gasket.

Oil cooler is raw water cooled and not likely to get in the block other than the water jacket...in raw water cooled engine.

Head gasket or cracked head/block if there's lots of water in the oil...or leak in intake manifold/gasket or not tightened down.

Is water/oil mixed (chocklately) indicating the engine has been run with contaminated oil?

Click to expand...


The engine is in fact raw water cooled. The engine has definitely ran with water in the pan. It's all over the dipstick (milky). I believe this is why the previous owner sold it. I think he gave up on trying to figure it out.

Good point on the rings and riser gasket (duh). That probably rules riser gaskets out. Why do you say the oil cooler is probably not the culprit? So that leaves intake manifold gasket, head gasket, or cracked head/block, correct?
 
i had this on a boat, replaced risers and mainfolds turned out when i pulled the heads there was a hole in one of them from corrosion.
 
Salt water? If left in the water or not flushed the block may not last more than 5-7 years.
 
Charlie - See my post above and comment if you have a second.

Thanks again.
 
Oh, If you're talking about the oil cooler, oil pressure is generally many times higher than the cooling system. A raw water cooled engine probably doesn't have more than 2-3 PSI(or so) because it's just flowing out of the system. A closed system with a heat exchanger will build up quite a bit of pressure comparatively but it generally has a 14 PSI pressure cap(raises the boiling point) and allows a more even running engine temp through out the block.
 
quote:
Originally posted by jtybt15

Oh, If you're talking about the oil cooler, oil pressure is generally many times higher than the cooling system. A raw water cooled engine probably doesn't have more than 2-3 PSI(or so) because it's just flowing out of the system. A closed system with a heat exchanger will build up quite a bit of pressure comparatively but it generally has a 14 PSI pressure cap(raises the boiling point) and allows a more even running engine temp through out the block.

Click to expand...


Ok makes sense. So definitely leaning towards intake manifold and or head gasket.
 
Could still be cracked block...could be the reason it was sold.[:I]
 
If the previous owners maintainence is suspect my guess is cracked block from lack of winterization.
 
quote:
Originally posted by mdoherty

If the previous owners maintainence is suspect my guess is cracked block from lack of winterization.

Click to expand...


Well it could very well be a cracked block, but I doubt it would be from a lack of winterization.

Putting together the pieces of the puzzle here is what I am able to determine. Previous owner bought the boat and the engines were toast. He rebuilt both engines and had both drives resealed, blasted, and painted. He rebuilt the motors himself. From what I've found, he overheated the motor(s)? at least once after rebuild because the thermostats lacked a couple holes drilled in them (the boat is an off shore style race boat with crossover cooling - no engine block style water pump). Subsequently he replaced the head gaskets at least once, if not twice. Apparently he also tuliped a valve on the one engine. It appears as though he was chasing this water issue for a while and hence why he got rid of the boat.

I am unsure the best route to take to get the boat on the water at this point. Either way, we are looking to get him on the water for the summer with the least amount of wrenching as possible. For the past 2 years or so, his old boat has been nothing but problems - Another off shore Apache with a Merc 8200 rpm race motor. He's done with that and back to an outdrive setup with twin 350's on this new boat.

We could screw around and pull the intake and look for any signs of the intake not sealing. We could then throw gaskets on it and retry. Chances are it will still leak. Then we'd pull it all over again and then pull the heads. If the head gaskets look ok, then what? Manuflux the heads? Deck the heads too while they're off? Throw new head gaskets on again and retry a second time? Now we're into it $200 for gaskets, $100 to deck the heads, $100 to manuflux? And the problem still exists?

Should we purcahse a used marine 350 for a few hundred bucks, swap out his cam, intake, and other long block parts to just get him on the water and then look at rebuilding a motor over the winter? Or should we just cut our losses now and buy a reman long block and swap his cam, intake, etc into it?

Thoughts?
 
quote:
Originally posted by jtybt15

Oh, If you're talking about the oil cooler, oil pressure is generally many times higher than the cooling system. A raw water cooled engine probably doesn't have more than 2-3 PSI(or so) because it's just flowing out of the system. A closed system with a heat exchanger will build up quite a bit of pressure comparatively but it generally has a 14 PSI pressure cap(raises the boiling point) and allows a more even running engine temp through out the block.

Click to expand...


Charlie,
I used to agree with this. In Oct. 2010 while winterizing my engines, the port motor suddenly showed milky water AFTER the oil change. I had only run it about 15 minutes & was getting ready to run the antifreeze through. Did a final dipstick level check & saw the water. Tracked it down to the 8 year old oil cooler on a FWC 454. Replaced the cooler & after the next change oil started clearing up.
Al
 
Wellll, Sh*t Al, Ya learn something new every day...and another thing, NOTHING is written in stone.

Sometimes a valve job can be 'over done' or the head ground too many times and you go thru the 'hardened' area of the seat. Did that once and sucked an exhaust valve. At the time, it was explained to me the exhaust got so hot, the ex seat got soft. Make sure the exhaust valves ride as high as possible in the exhaust seat. That way you know it ain't been over ground or too many times....happens when you go too cheap with junkyard heads and not sure what you're gettin'.[:I]

Just curious! What is it about his present long block parts that are so desirable. An engine is capable of making just so power in a given WOT range. The more HP you try to get, the higher (and narrower) the torque ban and HP range will be...and the higher you'll have to go with the compression and octane.

in other words, what are your build #'s gonna be? Too much cam on an otherwise stock engine and you might be going backwards.
 
quote:
Originally posted by lobsta1

quote:
Originally posted by jtybt15

Oh, If you're talking about the oil cooler, oil pressure is generally many times higher than the cooling system. A raw water cooled engine probably doesn't have more than 2-3 PSI(or so) because it's just flowing out of the system. A closed system with a heat exchanger will build up quite a bit of pressure comparatively but it generally has a 14 PSI pressure cap(raises the boiling point) and allows a more even running engine temp through out the block.

Click to expand...


Charlie,
I used to agree with this. In Oct. 2010 while winterizing my engines, the port motor suddenly showed milky water AFTER the oil change. I had only run it about 15 minutes & was getting ready to run the antifreeze through. Did a final dipstick level check & saw the water. Tracked it down to the 8 year old oil cooler on a FWC 454. Replaced the cooler & after the next change oil started clearing up.
Al

Click to expand...


Ok I'll throw the oil cooler as a possibility to check. Thanks.
 
quote:
Originally posted by jtybt15

Just curious! What is it about his present long block parts that are so desirable. An engine is capable of making just so power in a given WOT range. The more HP you try to get, the higher (and narrower) the torque ban and HP range will be...and the higher you'll have to go with the compression and octane.

in other words, what are your build #'s gonna be? Too much cam on an otherwise stock engine and you might be going backwards.

Click to expand...


I believe the engines had mostly stock rebuilds minus the cams. I have the specs on the cams. To me I would want to have the same cams in both motors from a symmetry standpoint, no? I don't think you would want one engine making 250 hp and one engine making 325 or so, would you?
 
So to update this thread -

1. We pulled the manifolds and found water tracking rust stains on the center two cylinders on one side of the motor. This obviously points to a leaking riser gasket. We separated the riser/manifold and found the gasket to be fully in place. It actually tore in two when taking the joint apart. So it appears as though the leak may have been there previously?

2. Before we did anything else, we pulled the plugs and found several of the plugs wet on that same side of the motor that contained the suspect manifold. We cranked the motor over and sure enough some light misting of water came out the center cylinders.

3. We pulled the intake and visually there was rusting inside the intake tract on the head with the same center cylinder. Only one center intake tract was rusted. The coolant crossover ports appeared to be sealing fine and it didn't look like water was flowing into the lifter valley. The gaskets were the good Felpro style with sealing rings around every port, plus the seller used some RTV on the coolant ports.

4. We pulled the heads and found a couple of interesting things.... 1. Exhaust valve was changed on the center cylinder which agrees with the research I was able to turn up on the seller. He said the one valve tulliped at some point? 2. The heads are casting number 14096217 and the valve spring cap/hat (whatever they are called) appear to be swapped intake/exhaust on that same suspect cylinder. I don't know that it makes a difference? 3. I could not see anything definite that points to a leak on the head gasket. I was able to visually see the coolant ports had made what appeared to be sufficient marks on the gasket indicating good clamping load. I did find the head locating pin to be very very short on the one side of the block. The pin barely holds the gasket itself. The block surface on the suspect side of the motor definitely does not appear to be prepped as well as the good side. I think a honing stone needs to be run over the entire surface before we even think about reassembling.

5. With both the head and the intake off, there is definitely a ton of water in the oil.

6. My buddy planned to make some testing rig in order to pressurize and test the oil cooler for leaks.

At this point I am somewhat stumped. I can't definitively say we've found the problem. If the oil cooler checks out OK, then I guess we'll get the heads cleaned up and pressure checked. Maybe that will provide some insight. If that turns up OK, I don't know how we should proceed from here. Any advice? Should we just buy another long block for $1500-$1800 and be done with it? What are the chances that the heads check out OK, we reassemble and the problem still occurs? Again any advice would help.
 
Oil cooler was pressure tested at 40psi. It held pressure overnight.
 
Once he gets the water in the oil figured he out he should really put the circulator pump back in. those crossovers are tricky. running wide open they work great. when operating at low rpm's no water is circulating at all if the thermostat is closed.you get hot spots and thats probably how it overheated in the first place. operating without thermostats presents problems too. at low rpm the engine never gets hot, all sorts of problems with that too.if he insists on keeping them he should probably run with out thermostats. the motor looks alot neater without the circulator pump and you might gain a few hp. for day to day use though he should put the pump back in.
 
I wasn't sure what you were referring to about the cross-over.If in fact the circulating pump was eliminated, I'd do what Zane recommended.
Go to Offshoreonly and ask questions there. They deal with your friends type boats. I don't know any of their 'tricks of the trade'. I presume you have a raw water pump. What make/model is it. Mostly I'm asking cuz of the number of over-heating incidents. Sounds like the cause was never fixed, sooooo...replacing the block at this point may just lead to another over-heat.

What were your compression test #'s? Did you do a leak-down test?

At this point, I's inspect each cylinder wall with the piston all the way down. Same with the heads and mating surface. Looking for cracks. Put a straight edge on the heads and block and look for warpage.

What we don't have is info on how the engine was running prior to any of the over-heat. Could the water in the center cylinders be caused by 'reversion' or back-fire?

What make/model is the engine/drive train (inboard, I/O?) You may have already said but I haven't re-read everything.
 
I'm a bit curious how water/rust got in the intake. You talkin' about the heads runners or intake manifold.

This is really one of those cases that need visual inspection to see what's going on. How much experience did the previous owner/builder have with marine engines? My first engine rebuild I had the heads done my a friends machine shop. Surrrrre, he knew how to build a marine engine. ALL the exhaust valves got 'sucked'.
 
You must log in or register to reply here.
Back
Top