Just Had a "HOLY S**t" moment - Need Advice (Mercruiser 470)

[djfam]

I am pretty sure what the answer will be to this question (and I am sure it is NOT GOOD):

1983 Mercruiser 470 - has always ran like a champ except for when i needed to rebuild the carb a few years ago. I also replaced the entire fuel system including tank and all lines last year.

Was de-winterizing the boat today - checked all oils, fluids, anti-freeze, belts, fuel, etc. Getting boat ready to go to the dealer on monday for a tune-up. The boat ran 15 minutes, then i had a sputter and what looked like a mix of oil and water came out the vent from the crank case (next to the flame arrestor). Not just a few drops, but about a cupful. I knew this was not good and to say i am totally deflated right now would be an understatement. I think i am looking at something terminal (i.e: cracked block perhaps?). I'd like to get some advice from the great folks on this forum to let me know their thoughts. Is this a terminal issue or is there a possible reason for this that i am overlooking.

This could be the end of my boating for the foreseeable future as in this economy, i will not be in for an engine replacement at this time.

thanks.

 

[zbnutcase]

Re: Just Had a "HOLY S**t" moment - Need Advice (Mercruiser 470)

Well it shouldnt be a cracked block if it had the proper mix of anti-freeze in it. My guess is head gasket.

 

[180shabah]

Re: Just Had a "HOLY S**t" moment - Need Advice (Mercruiser 470)

Do compression test, and pressure test the cooling system. You'll know for sure pretty quick.

 

[djfam]

Re: Just Had a "HOLY S**t" moment - Need Advice (Mercruiser 470)

Thanks for the responses...

The coolant levels and oil levels were both fine although i did not check them again after the fact and the coolant mix was correct (50/50). I'll do a compression test and check that. I dont think i have the tools to do a pressure test on the cooling system, so i"ll need to schedule a visit to the dealer for that. If it is just a head gasket - i know that is not an easy job but is it one i can do on my own? Any special tools required?

I'll keep you updated.

 

[betayv]

Re: Just Had a "HOLY S**t" moment - Need Advice (Mercruiser 470)

I think will be cheaper if you buy a tester and do it yourself taking to the dealer can cost a lot of $$$$$. Or look for a good boat shop the dealer always charge more.

 

[ken_23434]

Re: Just Had a "HOLY S**t" moment - Need Advice (Mercruiser 470)

You can "rent" the cooling system pressure tester for free from Autozone via their "Loan a Tool" program.

They will charge you for it upfront, and when you bring it back they refund you the full amount. Or, you can just buy the tester outright. I think the tester is somewhere around $60 to $100 there.

http://www.autozone.com/autozone/inourstores/lat/latLanding.jsp?bodyContent=heatingAndCooling

That link will show you the tester, but it did not show a price.

 

[sdoomaha]

Re: Just Had a "HOLY S**t" moment - Need Advice (Mercruiser 470)

Yes, if you can turn a wrench and follow instructions, you can change the head gasket. If you are familiar with the motor, only takes a couple hours with 2 guys. Not familiar, can take an afternoon. No specialized tools, but make sure you have a good torque wrench when torqueing down the head,,,and make sure you follow the correct sequence.

Good luck.

 

[djfam]

Re: Just Had a "HOLY S**t" moment - Need Advice (Mercruiser 470)

As i think about addressing this issue, it seems to me that I need to get the water out of wherever it is in the motor and since the oil and water mixed (somewhere - presumably inside the crank case), I presume i need to drain the oil as soon as possible, correct? I am going to try and get this work done this coming weekend (I'm travelling all week for work), but I think letting the water/oil mix sit in the engine is not a good thing. Any other areas i should drain or is draining all the oil the correct thing to do?

Thanks again, in advance, for your comments.

 

[djfam]

Re: Just Had a "HOLY S**t" moment - Need Advice (Mercruiser 470)

So i have yet to check anything (hopefully tonight), but i've spent a lot of time looking through posts trying to find additional answers.

A lot of guys say to check the exhaust manifold and riser as they can deteriorate and rust out letting water into the engine. Should I also check this? If so, how? I'm guessing taking off the manifold and pressure testing would be best?

This boat was run in saltwater most of its life and i dont know how well the previous owner took care of it. Could this be another potential issue i need to look at?

 

[djfam]

***UPDATE***Re: Just Had a "HOLY S**t" moment - Need Advice (Mercruiser 470)

***UPDATE***Re: Just Had a "HOLY S**t" moment - Need Advice (Mercruiser 470)

My aplogies for taking so long to the guys who provided advice. Work schedule and weather worked against me this week.

I just checked the compression and here is what I have:

1-140#
2-110#
3-125#
4-130#

They are a bit over the place and I am concerned about #2. I dont think I like a 30# spread from high to low cylinder. BUT... do I have some hope here? Do these numbers show a cracked block? Perhaps a head gasket, but maybe not the block? Also, I was wondering what folks thought about the exhaust manifold/elbow question? The more I research, the more I am leaning towards that, but I have no experience with it. You guys are the experts, so what do you think?

Again, I REALLY appreciate your responses.

 

[djfam]

Re: Just Had a "HOLY S**t" moment - Need Advice (Mercruiser 470)

By the way....since i didnt mention it,

There was no visible water in the cylinders upon visual inspection. I had half expected to pull the plugs and see one of the cylinders full. That may be my inexperience talking. I'm sure it would drain eventually. I turned over the engine (briefly - 5-6 cranks) before i took the compression readings to see if water came out. Nothing. Plugs were black but not wet. They definitely needed cleaning and I am embarrassed to say that I let them go for two years.

 

[natemoore]

Re: Just Had a "HOLY S**t" moment - Need Advice (Mercruiser 470)

You've got a pretty old 470. I'll bet you a million dollars that your engine needs to be overhauled. I bought an '87 boat with a 470 last year and I'm still wrapping up a complete engine rebuild (of course had a harsh winter AND a hip replacement....oh yeah and not much extra money).

Once you pull the cylinder head off (and I think you should at this point), you'll learn a lot. Mine had rust on the inside of the cylinders, plus gouges, scratches, and dents on the top of the pistons. I documented all this in several of my posts last year.

And now for some encouragement: I rebuilt my engine, transom unit, and lower unit for less than $2K. Did it a little at a time as I earned the money. The Mercruiser shop manual is very good, so, like others have mentioned, if you're half-way mechanical and can read and follow instructions, you'll do fine. Use this forum a lot, though!!!!

 

[solar7647]

Re: Just Had a "HOLY S**t" moment - Need Advice (Mercruiser 470)

have you checked the amount of Coolant in it yet? If so Is it low or have any oil in it?

This information will narrow down the possible places for your issue.

If you have the right amount of coolant in the engine this would suggest that it is indead water that mixed with the oil and would put you problem in your exhust manifold because that is the only area that water will be that has the potential to mix with oil. Considering the engines salt water like, the manifold is where I would start.

Now if you are low on Coolant, this suggest that the coolant is what mixed with the oil and increases the possible locations for the issue.
The two places that I would saspect if this is the case is the intake gasket or the oil seal for the cam. It could also be the head gasket, considering the compreasion readings it could very well be that. The most likely location of failure in the head gasket would be the intake side, since that would allow the coolant to mix with the oil Via the lifters.

In MO a cracked block prop not your issue.

 

[djfam]

Re: Just Had a "HOLY S**t" moment - Need Advice (Mercruiser 470)

Just checked the coolant and the level is fine and it is clean. No issues from what I can tell. I do have a very minor leak just below the overflow reservoir, but that looks like the clamp just needs to be tightened. Barely leaking - more wet with coolant than anything else.

 

[djfam]

Re: Just Had a "HOLY S**t" moment - Need Advice (Mercruiser 470)

NateMoore - thanks for the encouragement. I am willing to do what ever it takes to get this thing back going again, but my better half would have a few issues with another couple of grand being dumped into the boat. For me, it is worth it, but for her, not so much. I'll have to figure out a way of her not finding out.

I probably will end up pulling the head and changing the gasket at this point, but it looks like the exhaust manifold/elbow might be where this problem potentially gets solved. I'm looking at close to a grand for a new manifold/elbow set up, so maybe I'll try to get mine fixed at a machine shop.

By they way...nice plane in your picture. Did you fly them?

 

[solar7647]

Re: Just Had a "HOLY S**t" moment - Need Advice (Mercruiser 470)

Just checked the coolant and the level is fine and it is clean. No issues from what I can tell. I do have a very minor leak just below the overflow reservoir, but that looks like the clamp just needs to be tightened. Barely leaking - more wet with coolant than anything else.

This could be very important info!.......Now is your overflow mounted to the block in the lower left hand corner when looking at the engine? If so the coolant you are seeing could indicate the issue is the oil seal for the cam. But then again if your not missing any coolant it wouldnt be

 

[solar7647]

Re: Just Had a "HOLY S**t" moment - Need Advice (Mercruiser 470)

NateMoore - thanks for the encouragement. I am willing to do what ever it takes to get this thing back going again, but my better half would have a few issues with another couple of grand being dumped into the boat. For me, it is worth it, but for her, not so much. I'll have to figure out a way of her not finding out.

I probably will end up pulling the head and changing the gasket at this point, but it looks like the exhaust manifold/elbow might be where this problem potentially gets solved. I'm looking at close to a grand for a new manifold/elbow set up, so maybe I'll try to get mine fixed at a machine shop.

By they way...nice plane in your picture. Did you fly them?

Check ebay, you can get much better prices for these parts. Also if your going to take the head off and change the gasket be sure to give the head a good cleaning. If the exhust is where the leak is, the water is mixing with the oil in the head so you want to clean any water out.

 

[djfam]

Re: Just Had a "HOLY S**t" moment - Need Advice (Mercruiser 470)

The reservoir is in the upper right of the engine (if looking head on at the front)

I am already scouring ebay for parts. What about a machine shop? Can these be machined back into shape?

I really do value and thank you for your input.

 

[solar7647]

Re: Just Had a "HOLY S**t" moment - Need Advice (Mercruiser 470)

Well you must not have power steering then...good though, power steering would pput the resivoir in the lower corner and there is an out let in the same area that will leak if the oils seal for the cam was bad.

As for the manifold have you takin it off yet to see what your dealing with? Or in that case anything at all? Before you by parts we need to find the issue so your not wasting money.

I am not yet sure the issue is the manifold.

 

[djfam]

Re: Just Had a "HOLY S**t" moment - Need Advice (Mercruiser 470)

I did not get the chance to get the manifold off yet. I wanted to but I am in "supposed" to be babysitting my sick 7 year old. Wife will be home soon and I don't want the 7 year old to rat me out. Tomorrow is my wedding anniversary, so it will be Thursday at the earliest. Weather permitting I'll knock it out then. I'll refer to my manual once I find it, but how hard is it to get off? Doesn't look like it should be too bad. I'll take off the manifold and elbow in one shot if i can. When I get it off, what should I be looking for in both the manifold and elbow?