Mercruiser 4.3lx - Water in oil pan and milky oil

[Lou C]

I see signs of a blown head gasket between cyls 4&6, see that dark area? if you lift off the head gaskets, are the fire rings all in one piece or are they slit on the side anywhere? That was the cause of water in 2 cyls in my engine and about the same amount of milky oil. The cyl heads had cracks in the center cyls exhaust ports but those cyls did not have water, it was the #2 mostly and just a mist of water in #1.
I guess you can start with taking the cyl heads to a machine shop and get them checked out. When you pull off the head gaskets, clean up the block deck surface really well (no rotary tools!) and look very carefully for cracks.

 

[TurnerBFC]

Thanks guys for the input so far... I'm still totally lost. The air was very distinct when I had my ear up near the cyl #4 exhaust port. LouC, I will definitely investigate what you said and clean up the block and the head and check for cracks and then after that, I'll do as alldodge said and rig up some sort of plate and gasket to pressurize the cooling ports of the intake and head and then see if I can hear/find anything. And Rick, I will clean up the mess and look by the lifters lower in the valley.. any other ideas before I continue? I'm sure this one has you guys puzzled just as much as me!

 

[TurnerBFC]

Also thinking I shouldn't rule out the port side head and I should consider removing that as well..

 

[Lou C]

when you clean up the block look carefully for cracks around the cyl head bolt holes, some of the wind up in water passages.That might be a hint to how cooling water is getting into the oiling system.

 

[Lou C]

If you get the heads magnafluxed you’ll know if a crack in them was the cause...,

 

[TurnerBFC]

Yikes.. Looks like I still have my work cut out for me... wondering if I should just buy a motor for it

 

[Rick Stephens]

Do both heads. Have them magnafluxed. Find the problem then decide whether to replace the motor. That motor, if it is a cracked head, still looks brand new.

 

[TurnerBFC]

So if you guys could correct me if I’m wrong but here’s my action list:
-remove head on port side
-make block-off plates and pressure test cooling Passages of both heads and intake manifold (see if problem resides in one of these 3)
-have heads maganfluxed (local shop quoted me $40CAD/head)

Failing all of this, a new block..

 

[Rick Stephens]

Block is no different than heads, as far as disassembly and magnafluxing. Sounds about right for the job, he has to tank the heads before he can check them out. When machinist did mine he pulled all the valves as well. Then after magnafluxing he did all the valve seats since they were rusted and reassembled. Was not much over $120 for that.

 

[TurnerBFC]

OK kindly appreciate your help and insight... I'll get going on these !! Let's hope we can get it fixed up and others can reference this thread if they have similar issues. I'll be in touch soon guys!!

 

[TurnerBFC]

Quick question, I’m going to order the new head gaskets so I have them ready because if I need new heads or these turn out ok, etc.. I’m gonna need the gaskets anyways but I just want to verify that I should replace the head bolts or do you guys reuse them?

 

[alldodge]

Its not your issue but wouldn't hurt

 

[TurnerBFC]

Its not your issue but wouldn't hurt

I know.. this is starting to drive me crazy!! What would you do if you were in my position?

 

[alldodge]

I think the heads have been off at least 2 times already, so bolts have been torqued (stretched) twice. I would replace because this would be 3rd

 

[TurnerBFC]

I think the heads have been off at least 2 times already, so bolts have been torqued (stretched) twice. I would replace because this would be 3rd

OK thanks again alldodge.. I'll post back what the guy says after checking the heads. Let's hope we make some findings there...

 

[Gerhard Peters]

I had a similar situation as you. My boat has been standing without use for 2 years and it was not winterized.

My engine has cracks all over. On head had a hairline crack, boat exhaust manifolds had inner cracks and because of the cracks in the exhaust manifolds, the water got into the cylinders where the values where open. After taking the engine out and apart I found a big crack in the block on one side under the head. Since water had been sitting in two cylinders the had rust built up so the engine could not even turn.

I bought a used engine to replace it. I did a partial rebuild on the used engine. I took it all apart and did replace the main bearings and crank bearings, new piston rings and a full gasket set. I have lots of experience rebuilding engines so it was fund to rebuild. Now I know that I have a solid engine that will last a long time.

 

[Lou C]

as far as the head bolts, some of the newer ones used torque to yield bolts which you are only supposed to use one time. On my top end overhaul I changed the bolts because they were corroded from years of raw water cooling and so I picked up a set of ARP bolts for the cyl heads and intake. Also get a thread chaser to clean out those cyl head bolt threads and when you re-assemble make sure the bolts will thread all the way in. And yes use gasket sealer on them (Merc perfect seal, OMC gasket sealer or Permatex Aviation).
when you start re-assembling I strongly advise getting a merc shop manual or GM shop manual for that engine. on the newer ones the procedure for torqueing the heads is different and more complex, you have to get the right instructions for the year/gen that your engine belongs to...
Looking at your pix, you have a pre-vortec like mine so you can re-use the bolts but make sure the threads are REALLY clean because you want to get accurate torque on those head bolts
I used Fel Pro marine gaskets for the cyl heads and intake. Both fit and sealed well. There is a kit for that era 4.3 that includes all the ones you need and sealer for the china wall areas. I used an extra bit of Permatex on the water ports of the intake as there was slight pitting there.
the thing that took me the longest was cleaning the deck surface of the block and the bolt holes. Took hrs to get it just right. But, 3 years later and still good....
total parts cost for a pair of re-man 4.3 heads, gaskets and head bolts was about $800. I reused my old intake as it was still good. Also replaced the exhaust at the same time because it was due.

 

[TurnerBFC]

as far as the head bolts, some of the newer ones used torque to yield bolts which you are only supposed to use one time. On my top end overhaul I changed the bolts because they were corroded from years of raw water cooling and so I picked up a set of ARP bolts for the cyl heads and intake. Also get a thread chaser to clean out those cyl head bolt threads and when you re-assemble make sure the bolts will thread all the way in. And yes use gasket sealer on them (Merc perfect seal, OMC gasket sealer or Permatex Aviation).
when you start re-assembling I strongly advise getting a merc shop manual or GM shop manual for that engine. on the newer ones the procedure for torqueing the heads is different and more complex, you have to get the right instructions for the year/gen that your engine belongs to...
Looking at your pix, you have a pre-vortec like mine so you can re-use the bolts but make sure the threads are REALLY clean because you want to get accurate torque on those head bolts
I used Fel Pro marine gaskets for the cyl heads and intake. Both fit and sealed well. There is a kit for that era 4.3 that includes all the ones you need and sealer for the china wall areas. I used an extra bit of Permatex on the water ports of the intake as there was slight pitting there.
the thing that took me the longest was cleaning the deck surface of the block and the bolt holes. Took hrs to get it just right. But, 3 years later and still good....
total parts cost for a pair of re-man 4.3 heads, gaskets and head bolts was about $800. I reused my old intake as it was still good. Also replaced the exhaust at the same time because it was due.

Thanks LouC, I have the shop manual in .pdf format so I plan to print the pages and ensure I follow the correct torque sequence and values. My old GM 5.3 truck had the lifters fail so this process isn't entirely new to me... I just like that these are easily accessible to get to opposed to the truck! I haven't had time this week to remove the port side head (probably won't until Saturday/Sunday) so this thread may go quiet for a week or so but once they're removed I have a local guy for magnafluxing the heads and I'm really hoping we make a good finding there and we can relay the cause back to a cracked head(s).

Another question for ya.. is there an online store to get reman heads for this thing, OR is it a matter of finding a part out online somewhere? Also, do you know what size thread chaser I need for the head bolts? That way I can buy just the single chaser.

Thanks again for your help thus far since I started this thread!

 

[Lou C]

I got my reman heads from a local speed shop in Long Island that does engine work and has a machine shop (SK Speed, Lindenhurst Long Island) I think I paid $550 for the pair, and I also got the Fel Pro gasket set and the APR head bolts from them. The way to tell what size the thread chaser to get is to bring a head bolt to the store and they can match up the threads. If I can find it in my mass of tools I'll try to figure out which one I used (the one that's still dirty lol). I had a really hard time finding a thread chaser, everyone sells taps but only specialized tool stores sell thread chasers at least here that's how it is here. I found a set of them at Paramount Tools, Farmingdale Long Island. This place is the mother lode of high quality specialty tools and has been around forever, in fact they made machine tools for Grumman Aircraft Engineering and Republic Aviation Corp in the old days.

https://www.skspeed.com/

https://www.ptetool.net/

 

[Lou C]

reman cyl heads....