1997 4.3L GL Volvo (OMC) Water in oil

[Jprevat]

Ok, I know this has been brought up a thousand times, but I could really use some advice before I tear the top end off of my engine.

I got this boat for less than the price of the trailer just as a project and it seems I have definitely gotten in a little over my head.

This boat is a 1998 Sunbird 200SL with the 1997 4.3 GL and I know it was overheated before it came into my possession due to a failed water pump. Once I replaced the pump I have water mixing with the oil at a very fast rate. I had the mixture coming up through the vents on the valve covers. I pulled the plugs and checked the cylinders and I have no water intrusion.

Does this sound like it could be a head gasket or cracked block, or did I maybe dodge a bullet and just need to look at the intake and gasket for it?

If anyone has any knowledge in this matter or need any more details please feel free to point me in the right direction.

Thanks in advance yall.

 

[HT32BSX115]

------------I had the mixture coming up through the vents on the valve covers. I pulled the plugs and checked the cylinders and I have no water intrusion.

Does this sound like it could be a head gasket or cracked block, or did I maybe dodge a bullet and just need to look at the intake and gasket for it?

If anyone has any knowledge in this matter or need any more details please feel free to point me in the right direction.

Thanks in advance yall.

Howdy,

Don't tear off the upper end yet.........I would start by assuming it's a cracked block, since that is by far the most common cause of water in the oil..............and, since head gaskets don't usually fail and allow water into the oil.

You can test for that by pressurizing the cooling system using air pressure. Simply treat the block and heads as an air tank with multiple openings.

Close off all the openings (using hose and fittings from home depot etc)[disconnect the hoses to the manifolds/risers]

While you're at Home depot, get a plastic or brass ball valve and get a 0-30 psi air gage at your favorite autoparts store.

Close off all the openings and connect the gage and valve so that when the valve is closed, the gage will read pressure on the block.

Use an air compressor to pump up the block to approx 15 psi, close the valve and shut off the compressor.

If the block is cracked, it will not maintain pressure after the valve is closed. You can listen for air escaping. If it's on the outside, you can use a soapy water to find the crack(s). If it's inside, you'll hear it in a quiet setting....

Once you determine it's a cracked block, go to your favorite (truck) wrecking yard and find a similar year 4.3L V-6, swap all the marine stuff over to the truck engine and go boating!

Cheers,

Rick

 

[Jprevat]

Hmm well I am in the process of pulling all of the oil now. Well more emulsion than anything else. I am going to change out the intake gaskets since I have some spares on hand and the nearest home depot or lowes is more than an hour away.

If this doesnt change my situation I may go get another long block just to save on the headache. lol

 

[HT32BSX115]

Hmm well I am in the process of pulling all of the oil now. Well more emulsion than anything else. I am going to change out the intake gaskets since I have some spares on hand and the nearest home depot or lowes is more than an hour away.

If this doesnt change my situation I may go get another long block just to save on the headache. lol

More emulsion than actual liquid water probably means it was run that way.

Since you're going to have the intake off, you can look at the inside cyl area under the pushrods. That's where the SBC engines (4.3/5.0/5.7) like to crack because water pools there in the water jacket.

If the cracks are "old", you *may* be able to see evidence of it, but probably not.

The easiest way to test for block cracks is to pressurize. It doesn't have to be "Home Depot".......It can be any hardware/home store, or a well stocked "junk-box". You can even pinch off hoses using vise grips! (15psi is fairly easy to hold back.....(except in a cracked area)

A tiny bit of water in the oil will evaporate out fairly quickly once you run the engine at full operating temp. Obviously, if water is flowing into the oil faster than it can evaporate out, you get "milk-shake".

If the boat is in pretty nice shape, you might consider finding either a 5.0 or 5.7L V-8 too. either way, I would probably replace the manifolds and risers unless they look really good!)

 

[Jprevat]

I honestly havent had a chance to get the engine up to operating temperature. Ill look for those cracks and see what I can tell as soon as I take the intake off. It is a nice boat with solid interior and floors. will a 5.0 or 5.7 bolt up using the same engine mounts, wiring harness, and bolt up to the outdrive? I have more experience with Ford this is my first Chevy engine.

 

[Jprevat]

So I think I found the problem. There are two large cracks on the bottom of the intake underneath the thermostat.

Could this be causing my oil/water mix?

 

[Jprevat]

... and after more investigation two cracks on the inside of the cylinder walls underneath the push rods. Is there any way to temp fix this while I hunt for another long block?

 

[HT32BSX115]

... and after more investigation two cracks on the inside of the cylinder walls underneath the push rods. Is there any way to temp fix this while I hunt for another long block?

Nope. There just isn't any way to reliably seal those cracks in the block. (there are shops that can presumably weld them but it cost FAR more than just getting another engine!)

Some people use JB weld on outside cracks. Sometimes it works, sometimes not. Inside, it's impossible to get any sort of epoxy to stick to cast iron that is permeated with oil. Plus, it flexes slightly with heat/cool cycles. I wouldn't waste time trying to fix any cast iron cracks. Just find yourself a good truck 4.3 and swap everything over.

Pay attention to year model though, rear crank seals are slightly different (don't know when they changed) any truck engine will work ok. consider replacing the core plugs with brass and if you're going to operate in salt, get a marine circulating pump. Non-marine head gaskets can be a problem in salt water too.

If you're only going to run in fresh water, a truck block will work for a good long time......

 

[Jprevat]

Thank you so much for walking me through this. The cracks are on the inside and go all the way up to the deck where the head bolts up. Definitely not worth risking. It will only be used in fresh water so maybe a truck engine may be the best way to go. I have a line on a used 2000 model 4.3 long block for 800 but a used truck engine is close to the same price. Which would be the best way to go do you think?

 

[HT32BSX115]

If it's out of a truck, it has a fairly good approximation of a "marine" camshaft. ......low end torque, peak HP near 4800-5000 RPM.

A "car" V-6 may not perform as well. You want to be sure to be able to use your starter and intake manifold. Was your intake manifold cracked too? If so, you'll need to find another one..... is it a 2bbl or 4bbl carb?

I cannot tell you which year is best, someone should jump right in here and tell you which year would be the best choice to replace your 97 engine.....

On the other hand, If you want to swap to a 5.0 or 5.7, it will bolt up to your flywheel housing but you may have to find different alternator and PS brackets.

Best bet there is to find a complete engine or rotten boat with a 5.0/5.7 in it and pull the engine so you have all the doo-dads needed. Going to a V-8 will be good since it's always better with more power! Side engine mounts may have to be relocated slightly, but that's not all that hard.

 

[Jprevat]

I have a line on a few short block 4.3s that I would be able to throw my heads on and be good to go. I will need a new intake manifold as mine was busted as well. I have the 2 bbl holley setup.

I gave some thought to the v8s but honestly I want to keep the 4.3L.

Thank you again for taking the time to help me out.

 

[HT32BSX115]

I have a line on a few short block 4.3s that I would be able to throw my heads on and be good to go.

Nothing wrong with the 4.3L V-6. One of the best engines ever used in a marine application. If you're going to use your original heads, I would have them checked out by a machine shop for cracks, maybe do a valve job, check for flatness, etc...

 

[Jprevat]

If I go used engine I may have to get these heads checked. Whatever I put in there I want to stay there for a good long while.