Mercruiser 4.3lx - Water in oil pan and milky oil

[Rick Stephens]

If it's in the block you are gonna have to pull the motor, so might as well have at. Pull the motor down and then the shop can tank it and magnaflux it if you don't see a crack. I did exactly that when I had the same issue on a boat I bought that was full of water. Never did find a crack and the rebuild was cheap. Machine shop had several good V6 blocks sitting around that they offered me if I needed one. I decided to go with the one I had even though we had no idea where the water came from. Four years later I figure the water was rain water from previous owner leaving the spark arrestor off.

 

[TurnerBFC]

I’m leaning towards a new motor and am about to ask the obvious (and probably most asked) question...
can I put an auto engine into it? I found a GM 4.3 Vortec for $300 and I was thinking I’d swap my heads over, intake manifold, carb, exhaust manifolds and risers, etc and use that in the boat. Is there any reason I could not go this route? Would love some input ... I’m assuming the block I currently have is a total loss and will end up at the scrap yard... thanks again guys!

 

[Rick Stephens]

Have to change core plugs to brass, swap to a marine water pump, use marine gaskets (Felpro!) and if you get a block from a car and not a truck, you will want to change the cam to a truck cam.

 

[nola mike]

Core plugs on my junk yard engine were brass already (2001 Blazer). Also found that I couldn't get a felpro gasket set for vortec intake. I ended up with a mahle set. Looks like you have a non balance shaft v belt setup? If so, you'll need:
1. New water pump. Old one won't clear the new composite timing cover.
2. You'll need to trade out your harmonic balancer. I had a hell of a time with this.
3. The new block may be metric, in which case you'll need new hardware for the starter, flywheel cover, and motor mounts
4. New starter if metric. M10 bolts won't fit the starter holes. You could probably drill out the holes a bit, but I didn't feel like messing with it and upgraded the starter to a pmgr anyway.
5. New motor mounts. The non balance shaft engines have solid mounts and use different mount bracket. Otherwise you'll need to stick with the fluid mounts you have (otherwise the mount height will be off)

​​​​​​Check out my swap thread for more details.

 

[Lou C]

Read Nola Mike's thread on the complexities of the long run of 4.3 engines, the devil is in the details, and you really want to stick with whatever generation all your old stuff is from. Having said that, look at the lifter valley very carefully, look at the sides of the block, and all round the bolt holes for the cyl heads. If you still have the old head gaskets, show them to the machinist. It could be as simple as that, I had the same problem but I know for sure that a bad overheat 3 seasons prior is the likely cause. That would enable you to not have to pull the engine and get the boat back together with all your old accessories just with a Fel/Pro gasket set and maybe a set of new head bolts. JUST MAKE SURE ITS NOT THE HEAD GASKETS before proceeding. Given how bad my engine overheated (running it that way was not just neglect, the boat was in danger of sinking, the little hose from the transom mount to the P/S cooler popped off, pumping salt water in and overheating the engine at the same time) I thought for sure the block would be cracked but it was not. The heads had very small cracks in the center cyls exhaust ports but that didn't let in water. It was all the head gaskets...Fel Pro makes a very nice set of marine quality HGs for the 4.3....

 

[TurnerBFC]

Core plugs on my junk yard engine were brass already (2001 Blazer). Also found that I couldn't get a felpro gasket set for vortec intake. I ended up with a mahle set. Looks like you have a non balance shaft v belt setup? If so, you'll need:
1. New water pump. Old one won't clear the new composite timing cover.
2. You'll need to trade out your harmonic balancer. I had a hell of a time with this.
3. The new block may be metric, in which case you'll need new hardware for the starter, flywheel cover, and motor mounts
4. New starter if metric. M10 bolts won't fit the starter holes. You could probably drill out the holes a bit, but I didn't feel like messing with it and upgraded the starter to a pmgr anyway.
5. New motor mounts. The non balance shaft engines have solid mounts and use different mount bracket. Otherwise you'll need to stick with the fluid mounts you have (otherwise the mount height will be off)

​​​​​​Check out my swap thread for more details.

Thanks for your detailed reply - I have some homework to do before I make a decision, no doubt!

 

[nola mike]

I probably would have kept my squish mounts if the base of one of them hadn't been thin/corroded. New hard mounts were $40 each, but like I said, you need the brackets as well. I picked up a used set of brackets/hard mounts on ebay for $75. Didn't make sense to buy new squish mounts since they're for a much more limited application and they're not really correct with a balance shaft engine anyways. The new mounts and brackets appear to be common among all the v8s and balance shaft v6s.

 

[TurnerBFC]

Read Nola Mike's thread on the complexities of the long run of 4.3 engines, the devil is in the details, and you really want to stick with whatever generation all your old stuff is from. Having said that, look at the lifter valley very carefully, look at the sides of the block, and all round the bolt holes for the cyl heads. If you still have the old head gaskets, show them to the machinist. It could be as simple as that, I had the same problem but I know for sure that a bad overheat 3 seasons prior is the likely cause. That would enable you to not have to pull the engine and get the boat back together with all your old accessories just with a Fel/Pro gasket set and maybe a set of new head bolts. JUST MAKE SURE ITS NOT THE HEAD GASKETS before proceeding. Given how bad my engine overheated (running it that way was not just neglect, the boat was in danger of sinking, the little hose from the transom mount to the P/S cooler popped off, pumping salt water in and overheating the engine at the same time) I thought for sure the block would be cracked but it was not. The heads had very small cracks in the center cyls exhaust ports but that didn't let in water. It was all the head gaskets...Fel Pro makes a very nice set of marine quality HGs for the 4.3....

Hey Lou, thanks! I like what you're thinking and I'm going to pick up the heads today. I still have the head gaskets so I will grab those quickly and I am going to take them with me to get his input since this is what he does and sees everyday. For the FelPro gaskets (if I decide to go that route based on everything) do you have a part number? The dealer wants $100CAD for each gasket... Thanks again guys... we will figure out where this water is coming in from!!

 

[TurnerBFC]

I found this... is this the marine application?
https://www.amazon.ca/Fel-Pro-17211-Head-Set/dp/B000CMESPY

 

[nola mike]

I found this... is this the marine application?
https://www.amazon.ca/Fel-Pro-17211-Head-Set/dp/B000CMESPY

Yes, but you'll need a separate intake manifold gasket for the vortec (also, that's about double the price as you can find elsewhere, even CDN). Like I said, I ended up with the mahle set, which should work well and includes the correct intake gasket (the head gasket is composite).

 

[TurnerBFC]

Yes, but you'll need a separate intake manifold gasket for the vortec (also, that's about double the price as you can find elsewhere, even CDN). Like I said, I ended up with the mahle set, which should work well and includes the correct intake gasket (the head gasket is composite).

Ok great but my engine is non vortec, Serial No. 0D810408 so I think these intake gaskets would work?

 

[nola mike]

Sorry, yeah. Misread post #82. But if you end up needing new heads, might as well upgrade to some vortecs.

 

[TurnerBFC]

Sorry, yeah. Misread post #82. But if you end up needing new heads, might as well upgrade to some vortecs.

Thanks Mike, I just did some intense reading on your swap thread... I gained a lot of valuable information on there. How does your boat run without swapping the cam over to a marine spec cam? I have a motor lined up already if it comes down to it! Thanks again for your insight.

 

[Lou C]

QUOTE=TurnerBFC;n10888859]I found this... is this the marine application?

https://www.amazon.ca/Fel-Pro-17211-.../dp/B000CMESPY[/QUOTE]



yes it is and is the same one I used on my top end overhaul...
https://shop.advanceautoparts.com/p/...211/20680441-P

PS if your old heads are good it saves you a good amount since you can keep the old intake as well. I paid about $550 USD for a pair of reman pre-vortec 4.3 heads which was reasonable I thought...while the Vortec puts out a good 20 hp more, I think the older pre-vortecs were less troublesome in some ways, no issue with leaky intakes, no balance shaft which can start making noise, etc.
Try taking really good high res pix of the block deck surface and cam valley (clean it up well after you've removed the lifters). I did this and took it to my mechanic and he advised looking at it real close with a magnifier.

 

[TurnerBFC]

Ok so here's my update for the night (and probably rest of weekend as I am heading up to the cottage) but I cleaned up the block well tonight in the lifter valley and attached the photos here. The machine shop said the heads were fine and I also showed hi, the head gaskets as LouC suggested and he said they don't show anything that would give rise to my issue. HE did mention for me to bring the intake manifold back to him and he would magnaflux it for me free of charge, and also to bring the entire boat and he said we can make an attempt to flux the block in the boat... anyways, let me know what you guys think based on these pictures. I spent a good chunk of my night just staring at the block and nothing caught my eye... Thanks again, guys!!!

 

[nola mike]

Thanks Mike, I just did some intense reading on your swap thread... I gained a lot of valuable information on there. How does your boat run without swapping the cam over to a marine spec cam? I have a motor lined up already if it comes down to it! Thanks again for your insight.

Ha ha, obviously you didn't make it to the end of the thread...I'll let you know when I get it done. But conventional wisdom is that a truck cam is at least close enough, if not identical to the merc.

 

[Lou C]

Ok so here's my update for the night (and probably rest of weekend as I am heading up to the cottage) but I cleaned up the block well tonight in the lifter valley and attached the photos here. The machine shop said the heads were fine and I also showed hi, the head gaskets as LouC suggested and he said they don't show anything that would give rise to my issue. HE did mention for me to bring the intake manifold back to him and he would magnaflux it for me free of charge, and also to bring the entire boat and he said we can make an attempt to flux the block in the boat... anyways, let me know what you guys think based on these pictures. I spent a good chunk of my night just staring at the block and nothing caught my eye... Thanks again, guys!!!

Ok in these pics, there is a brown line vertically extending on both sides, is that just leftover milky oil stain or something else? Hard to tell in the pic, clean it up again with some solvent...

 

[TurnerBFC]

Ok in these pics, there is a brown line vertically extending on both sides, is that just leftover milky oil stain or something else? Hard to tell in the pic, clean it up again with some solvent...

I think I brought this up back a few pages.. both sides have it... I wondered if this was an indication of something but nothing on the heads or the block. Maybe HG??? This was cleaned up with solvent prior to these pics

 

[Rick Stephens]

I think those are paint marks from the factory. Not sure what they indicate, but my motor had them as well.

 

[TurnerBFC]

Felpro gasket kit is coming tomorrow or Thursday... this is my last bit of insurance to know whether or not it was/is the head gaskets. I should also add I used an inspection camera I had and poked around inside the water jackets, etc... but didn't notice anything (lots of rust so hard to see). I'd like to look at making block off plates as alldodge suggested earlier, but put them on the block deck surfaces so I can pressurize again... not sure yet how to do this but I'll put some thought into it...