Water In Oil

I know this question comes up a lot, but cant find anything pertaining to my problem. I have an 83 MerCruiser 120 that I just got from a guy and it hasn't been winterized in a couple years or running since then. The oil was milky on the dip stick so I drained the pan and got a quart or two of water out before the oil started coming out. I seen a line of rust on the side of the engine block that looked like it was a drip from either the exhaust manifold or the head gasket so I took the manifold and head off. The head gasket looked good and didn't see any cracks or areas that allowed any kind of blow by. The manifold gasket looked like it was in good shape also but then it tore apart when the manifold came off. I had no water or rust in the cylinders so what is my next step? I have all the old gasket material taken off and surfaces clean up and see no cracks on manifold or head. I looked down each cylinder with pistons in lowest position and see no cracks. What would be my next step or what are anybodys thoughts? I know nothing about the manifold or risers so if someone could give me some input on this as well if there is anything I should be checking there?

Thank you!!

Replace the head and manifold (with new gaskets, of course). Replace the oil and filter, apply cooling water to the engine, and run it up to operating temperature. Start looking for external leaks. Run the engine for 10-15 minutes, and check for water intrusion in the oil.

Ok...I guess that was my plan. Didn't know if there was anything specific to look at before I throw the head and manifold back on. It will be a week or two before I get the gaskets and head bolts. I heard you should always use new head bolts, is this true or shouldn't I spend the $100 on new ones? You don't know what the torque happens to be for the head and manifold bolts do you? Do I start with center bolts and work my way out? Ill be sure to post a reply when I get things put back together with an update.

You should be able to re-use your head bolts, as long as they are not corroded. Clean them up with a wire wheel and use anti-seize when assembling. Here's a couple of links for your torque specs.

http://www.marineparts.com/mpf/mpf520.aspx

https://www.perfprotech.com/blog/articles/mercruiser-30l-mechanical-specifications#

Devon said:

I know this question comes up a lot, but cant find anything pertaining to my problem. I have an 83 MerCruiser 120 that I just got from a guy and it hasn't been winterized in a couple years or running since then. The oil was milky on the dip stick so I drained the pan and got a quart or two of water out before the oil started coming out. I seen a line of rust on the side of the engine block that looked like it was a drip from either the exhaust manifold or the head gasket so I took the manifold and head off. The head gasket looked good and didn't see any cracks or areas that allowed any kind of blow by. The manifold gasket looked like it was in good shape also but then it tore apart when the manifold came off. I had no water or rust in the cylinders so what is my next step? I have all the old gasket material taken off and surfaces clean up and see no cracks on manifold or head. I looked down each cylinder with pistons in lowest position and see no cracks. What would be my next step or what are anybodys thoughts? I know nothing about the manifold or risers so if someone could give me some input on this as well if there is anything I should be checking there?

Thank you!!

Click to expand...

Ayuh,.... Yer 1st mistake was pullin' the head, so now ya can't pressure test the motor's coolin' passages,.....

Pull the motor, flip it over, 'n pull the oil pan,....
You'll most likely see cracks along the manifold side of the block, inside, opposite the block's drain plug,....

No reason for new head bolts either,... Clean, 'n reuse the originals, so long as they ain't rusted out,... ei: the threads are gone,...

Thanks for the links. Great help!!

Well I guess I’m getting the head pressure checked for leaksbeings its out so I can rule out the head being cracked. Just over $10 to haveit checked. I would pull the engine but really don’t have the time for it and don’twant to stick any more money than I have to into it. I guess my thinking is if it’sanything more than the head or manifold it’s not worth fixing, because thatmust mean there is an internal crack on the block if I don’t see water coming outexternally somewhere right??? The boat is a 83 and nothing pretty so just notworth a whole lot of anything to me, except if it’s a cheap fix.

Ok so I took the head and manifold to have pressure checked and will not get them back till early next week. The guy said that the two center ports on the manifold looked bad on the surface where the gasket goes and it looked like water could have escaped there. I am having the head and manifold resurfaced if they pass the pressure test. My question is, is it possible for 2 quarts of water to get into the pan from a bad manifold or manifold gasket without the water having to travel down through the valves and cylinders?

The shop called me back and said the head and manifold checked out ok with pressure checking them, but he said the manifold would have to be resurfaced 50 thousands of an inch. Would this be ok to have done or not? I guess the guy was unsure if it would be worth to do it or if that much off would cause problems with the way it ran if this was the only problem. He also said that there was no way that it didn't have a gasket leak with that much of an offset, which is why I prob seen the rust mark on the same side of the block where it ran down.

It should not make any difference for your application. I would ask if he would try to mill it a minimum just to get it flat.

.050" seems like a lot..............

.050" off from the manifold surface is a bit unusal, be it won't be a deal breaker.

I agree with Bill.
When you prematurely pulled the cylinder head, you missed your oportunity to:
perform a cylinder pressure test.
perform a leak down test.
perform a clyinder block and cylinder head cooling system pressure test.


If the boat is OK and meets your needs, it may be worth repairing or even replacing the engine.


.

Thanks for all the input guys. Next time I wont be tearing things apart so soon. Ill go ahead then and have him resurface the manifold. I thought is was quiet a bit too beings it just had some minor pitting. This is a guy I know nothing about so who knows if he knows what he is doing either. He just opened up shop. I moved away from a really good machine shop that worked with racing motors and knew every in and out, so I'm w/o their knowledge and help now. They were cheap and had no problem teaching a person some things.