Milky oil

SeaRayboater95 · 2026-09-12T11:01:30-0600

Hey Guys and Gals.
Not sure what to do. I suspect the risers and manifolds. Possibly head gasket. Buddy doest want to put any more money into it now. Can we lay it up like this?. Also, how does I locate where the water is coming from. Can I run it like this to see how much water it adds to the oil? Started it many times and no hydrolock. Not sure how to proceed.
Thanks,

Ken

alldodge · 2026-09-12T11:24:30-0600

SeaRayboater95 said:
Not sure what to do. I suspect the risers and manifolds. Possibly head gasket. Buddy doest want to put any more money into it now. Can we lay it up like this?. Also, how does I locate where the water is coming from. Can I run it like this to see how much water it adds to the oil?

No, No, unless ......... you want to have rusted and scored internal like bearings.

Need to get the water out and have everything coated with oil, if any water is present it will rust. There is no short cut

It won't cost much to take things apart, only when putting back together. Take exhaust mans off to see if that's the problem. Can use a drill with a oil pump fixture to pump clean oil thru without starting motor

SeaRayboater95 · 2026-09-12T11:39:20-0600

alldodge said:
No, No, unless ......... you want to have rusted and scored internal like bearings.

Need to get the water out and have everything coated with oil, if any water is present it will rust. There is no short cut

It won't cost much to take things apart, only when putting back together. Take exhaust mans off to see if that's the problem. Can use a drill with a oil pump fixture to pump clean oil thru without starting motor

Thanks for that response.

Not sure how long it been run like that. Did a bunch of work, then changed oil and discovered this. Couldn't see it on the dip stick. How would I know when to stop throwing money at this boat?
It's a 96 4.3 Alpha1 Gen 2 in not bad shape.
Recently done;
New bellows(All, hoses too?)
New shift cable
New exhaust flappers
New trim senders
New cap, rotor, wires and plugs
New impeller kit and drive oil
Also, what do i need to move fresh oil through the motor.
Still......thanks

Ken

Ken

alldodge · 2026-09-12T13:01:00-0600

Search for "gm oil pump primer tool" and several will show up

Your motor may be fine, I'm just saying you need to get the water out if you want to keep it.

You can run any motor for 30 seconds without water, but do remove the drive.

Get all the water out, put fresh oil in and prefill the oil filter. Start it and stop after 30 seconds. Wait an hour and do it again. This will displace all the water out of the bearings

Your motor is ok to leave until you want to dig into it to find out where the issue is. If your in salt water than most likely the exhaust. If your in fresh water than I would look at intake and heads

Exhaust flappers were replaced, was it just because or was there an incident or was just time?

nola mike · 2026-09-12T13:46:38-0600

Was the oil level increased? Might try an oil change and run it on muffs for a while to see if it returns. You can pressure test the system to see where the leak is. Are you in freezing temps? If you don't want to mess with it any more, do as AD says...me, I couldn't sit all winter not knowing what was up. As for is it worth fixing, that's a personal call. Shouldn't take much to get a 4.3 running.

SeaRayboater95 · 2026-09-12T14:30:56-0600

alldodge said:
Exhaust flappers were replaced, was it just because or was there an incident or was just time?

Port side was was kinda floppy and the other side was missing.

SeaRayboater95 · 2026-09-12T14:33:45-0600

nola mike said:
Was the oil level increased? Might try an oil change and run it on muffs for a while to see if it returns. You can pressure test the system to see where the leak is. Are you in freezing temps? If you don't want to mess with it any more, do as AD says...me, I couldn't sit all winter not knowing what was up. As for is it worth fixing, that's a personal call. Shouldn't take much to get a 4.3 running.

Oil level was increased. Did an oil change and it milked up again.

SeaRayboater95 · 2026-09-12T15:14:39-0600

Can I run a cheap automotive oil filter to flush the oil? How would i find one at the parts store?

Ken

Lou C · 2026-09-12T15:20:41-0600

If the engine has good compression and doesn't make abnormal noises it is definitely worth finding out where the problem is now, before you winterize it.
It could be:
exhaust system, elbows, manifolds, gasket between the 2 (a '96 still has the wet exhaust system), if in salt water exhaust systems need periodic replacement.
intake manifold (if it is a Vortec with the 8 bolt intake manifold, the early gaskets were very problematic and would put water right in the oil via the cam valley), if in salt water they sometimes rust through right under the thermostat with the same outcome
cylinder heads, head gasket or block
I'd start with the exhaust system.
I was able to remove a plug on the top of my OMC/Volvo style exhaust and look down into the exhaust gas passage to see if it's leaking inside. Need an endoscope inspection camera of course, but that's a great tool to have for problems like this. The exhaust is the easiest of the causes to put right.

Lou C · 2026-09-12T15:21:49-0600

SeaRayboater95 said:
Can I run a cheap automotive oil filter to flush the oil? How would i find one at the parts store?

Ken

yes you can and just get a filter for a Chevy S10 pick up with the 4.3, try to find one that is for the non-remote filter set up.

nola mike · 2026-09-12T15:25:17-0600

Lou C said:
yes you can and just get a filter for a Chevy S10 pick up with the 4.3, try to find one that is for the non-remote filter set up.

Unless you have a remote filter

alldodge · 2026-09-12T15:27:12-0600

Remote non-remote, filter will be the same thread

Lou C · 2026-09-12T15:54:21-0600

But the diameter of the non remote (standard) filter on the V6 is smaller than on the V8s, it all depends on what remote set up if any is present. Even though the 4.3 is often referred to as 3/4ths of a 5.7, there are a number of differences. I bought a remote set up for my engine from Michigan Motorz and the remote filter base takes a Ford style filter so go figure lol.

SeaRayboater95 · 2026-09-12T16:02:49-0600

nola mike said:
Unless you have a remote filter

Have a normal one on the bottom, back port side

nola mike · 2026-09-12T18:04:15-0600

alldodge said:
Remote non-remote, filter will be the same thread

Lou C said:
But the diameter of the non remote (standard) filter on the V6 is smaller than on the V8s, it all depends on what remote set up if any is present. Even though the 4.3 is often referred to as 3/4ths of a 5.7, there are a number of differences. I bought a remote set up for my engine from Michigan Motorz and the remote filter base takes a Ford style filter so go figure lol.

Yeah, my remote filter from Summit is also Ford style.

SeaRayboater95 · 2026-09-12T18:17:12-0600

Is there and order to check these different possibilities? Is it visual, or do I need to pressure test? I remember from years ago that acetone was used some how to find damage in exhaust. Would like a definitive diagnosis before we buy parts

Grub54891 · 2026-09-13T06:40:10-0600

I usually dump the oil, put in the cheapest oil you can get along with the filter. Add a half can of seafoam, run it for a couple minutes. Repeat a few times and when the oil looks good fill with your normal oil. Seafoam helps flush the water out. This works if the water leak isn’t too bad. In your case, if it’s just being stored you can just leave the cheap oil in it for now, if it looks decent. More investigation is definitely needed.

Scott06 · 2026-09-13T07:11:13-0600

SeaRayboater95 said:
Is there and order to check these different possibilities? Is it visual, or do I need to pressure test? I remember from years ago that acetone was used some how to find damage in exhaust. Would like a definitive diagnosis before we buy parts

I would pressure test the block and heads to make sure they are not cracked if they are you know is exhaust or other water source.
you will need to change multiple times to get the water out of the oil. Issue will be if exhaust is still leaking water back in it’s not going to get you anywhere

SeaRayboater95 · 2026-09-13T13:45:47-0600

Ok, I've done a bit of exploring since we last talked. I've drained the oil and filter will screen the first oil change. Forgot to clean the pan on the milky one. When I pick up some oil and filters tomorrow, I will fill the engine and filter with oil, run for 30 seconds, with drive removed, and shut off. Run again in an hour, drain and repeat. Currently, I have the hoses on the water jacket blocked and pressurized to 10 lbs. Had a very slow leak coming from the hose from the power steering cooler bubbling from under a electrical tape repair. I believe that accounts for the very slow loss of pressure. I got a small piece of tubing and listened from the oil fill. pcv vents, dip stick, carburetor and exhaust. no hissing. Does that mean I don't have to open the motor? The culprit is likely the exhaust?

Ken

Lou C · 2026-09-13T14:17:32-0600

You really need a pressure gauge to accurately measure if the water passages hold pressure. A fuel pressure gauge will work.

Milky oil

Chief Petty Officer

Moderator

Chief Petty Officer

Moderator

Admiral

Chief Petty Officer

Chief Petty Officer

Chief Petty Officer

Supreme Mariner

Supreme Mariner

Admiral

Moderator

Supreme Mariner

Chief Petty Officer

Admiral

Chief Petty Officer

Admiral

Fleet Admiral

Chief Petty Officer

Supreme Mariner