mercruiser v6 4.3 water in oil

jenny · Jul 16, 2010

Help! I had a water oil mixture in the engine. I pulled the oil plug and water came pouring out. When it was done draining water, it drained a water and oil mixture. I checked the compression, and the compression was about 140 for each cylinder.

Bondo · Jul 16, 2010

Re: mercruiser v6 4.3 water in oil

Ayuh,... If this is the 1st run of the year,...
I'm guessin' you've got a Cracked Block, probably from improper winterization...

jenny · Jul 16, 2010

Re: mercruiser v6 4.3 water in oil

This is the second time taking it out, but the first time out was only for an hour before it died. I replaced the cap and rotor and it started up. So basically, this was the first time taking it out for a significant period of time. How can you tell if it is a cracked block?

Bondo · Jul 16, 2010

Re: mercruiser v6 4.3 water in oil

How can you tell if it is a cracked block?

Ayuh,... You have to isolate the blocks cooling passages by disconnecting hoses, plugging, etc, then pressurize with air, about 15psi...
You Hear the leak, then follow the sound...

When/ how often was the oil level Checked,..??

jenny · Jul 16, 2010

Re: mercruiser v6 4.3 water in oil

Have you ever heard of lock n stitch? If so, what is you thoughts on it.

Bt Doctur · Jul 16, 2010

Re: mercruiser v6 4.3 water in oil

If you think you see a crack or leakage please tell us.
Freeze cracking happen internally as well as externally, cant "stitch" the inside ones.

Bondo · Jul 16, 2010

Re: mercruiser v6 4.3 water in oil

Ayuh,... On an antique Unreplacable block,... Maybe...
On your 4.3l,... No way,... They're a dime a dozen...
And,...
It takes some mass to support lock, 'n stitching...
Where you block is probably cracked, the distortion will be unacceptable...

Welding, or epoxy won't work either on the Oil side...

jenny · Jul 16, 2010

Re: mercruiser v6 4.3 water in oil

Every time before I took it out, the oil was checked.

jenny · Jul 16, 2010

Re: mercruiser v6 4.3 water in oil

There is also water oil mixture on top of the engine. I don't know if this helps or not.

Bondo · Jul 16, 2010

Re: mercruiser v6 4.3 water in oil

Nope,... Still sounds like a Cracked Block...

Who winterized it,..??

jenny · Jul 16, 2010

Re: mercruiser v6 4.3 water in oil

I did. But I started it in April and then it froze again in May and June.

Bondo · Jul 16, 2010

Re: mercruiser v6 4.3 water in oil

jenny said:
I did. But I started it in April and then it froze again in May and June.

Ayuh,... There ya go,... Now ya need a new motor... Shoulda atleast Drained it...

jenny · Jul 16, 2010

Re: mercruiser v6 4.3 water in oil

A freeze plug was popped off when I took it out the first time.

Bt Doctur · Jul 16, 2010

Re: mercruiser v6 4.3 water in oil

trouble is it cracked internally before it pushed the core plug out,.

1961_lonestar_holiday · Jul 16, 2010

Re: mercruiser v6 4.3 water in oil

just for the heck of it keep running it until it dies! then get a replacement engine. just so you know your mercruiser 4.3 is just a regular old chevy 4.3

jenny · Jul 16, 2010

Re: mercruiser v6 4.3 water in oil

Thank you everyone for you help. It looks like I am looking for a new motor now.

jenny · Jul 16, 2010

Re: mercruiser v6 4.3 water in oil

I just found a used engine. How do I know if it is still a good engine? It is already taken out of the boat.

1961_lonestar_holiday · Jul 16, 2010

Re: mercruiser v6 4.3 water in oil

how much is it?

Bt Doctur · Jul 16, 2010

Re: mercruiser v6 4.3 water in oil

portable tank,hook up a battery, jumper from the +batt to the + coil,jump starter.add water.

fossill · Jul 16, 2010

Re: mercruiser v6 4.3 water in oil

jenny said:
A freeze plug was popped off when I took it out the first time.

They are not freeze plugs. A common misconception. They are casting plugs used to cover the holes where the sand is extracted from the block when it is cast at the manufacturing plant. Those plugs have nothing to do with offering any kind of freeze protection.

mercruiser v6 4.3 water in oil

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