470. Oil coming from valve breather tube

[jabfd]

Hello. I have oil coming from valve tube to carb when I run the boat . oil level is just passed the last L of full . So it's a over filled by 1/4 inch on the dip stick . Can this cause this ? Also when I take the oil fill plug out there is a lot of pressure coming out of it . And inside looks like white froth and under the cap as well. Motor runs good oil was just changed with 25 w40 the run after was when the probably started . Did compression test 145 to 155 on all cyl. Spark plugs look clean and only have about 8 hr on them . Any help would be great thanks

 

[Another retired guy]

Re: 470. Oil coming from valve breather tube

This is a strange one there shouldn't be pressure in the oil pan, and oil coming out of the rocker cover vent means it's full of oil ?? How much oil did you put in? It's either way over full or the drain passages through the head are plugged?

 

[jabfd]

Re: 470. Oil coming from valve breather tube

I put five qt in the oil level is a little high as I stated in the first post . Could that be it ?

 

[Another retired guy]

Re: 470. Oil coming from valve breather tube

I put five qt in the oil level is a little high as I stated in the first post . Could that be it ?

How much oil is coming out the breather tube? Solid flow? Spray?

According to a chart I have, the capacity of a 470 is 5 1/2 quarts, so it should be slightly low, not high. There's something else in there, and the white froth could indicate water

 

[jabfd]

Re: 470. Oil coming from valve breather tube

Not sure but it seems like a spray or mist it foams up at the carb but yesterday on a 30 min run there was a little oil that leak down the carb and on the top of the valve cover so the valve cover and down the back of the head was wet of oil . Not much oil but it wasn't dry

 

[Another retired guy]

Re: 470. Oil coming from valve breather tube

Not sure but it seems like a spray or mist it foams up at the carb but yesterday on a 30 min run there was a little oil that leak down the carb and on the top of the valve cover so the valve cover and down the back of the head was wet of oil . Not much oil but it wasn't dry

Is the valve cover full of foam?
Best thing to do now is to drain the oil again- make sure it's all out, and refill with fresh oil. If it happens again, I'm guessing water is getting in somewhere.

 

[jabfd]

Re: 470. Oil coming from valve breather tube

Is the valve cover full of foam?
Best thing to do now is to drain the oil again- make sure it's all out, and refill with fresh oil. If it happens again, I'm guessing water is getting in somewhere.

I do see some white foam in the valve cover not full but there is some there . I pumped oil out so I don't think the pump gets it all so that's why I only put 5 in there must be old only still left there . I will Change the oil again and see if it happens again .how can water be getting in

 

[Another retired guy]

Re: 470. Oil coming from valve breather tube

.how can water be getting in

Number 1 cause is a bad head gasket.

 

[jabfd]

Re: 470. Oil coming from valve breather tube

Number 1 cause is a bad head gasket.

Could it be a head gasket even though I have good compression 145 to 155 on all cyl. And the engine runs good

 

[Another retired guy]

Re: 470. Oil coming from valve breather tube

Could it be a head gasket even though I have good compression 145 to 155 on all cyl. And the engine runs good

Yes it could be. The gasket has to keep water passages sealed from oil passages sealed from the cylinders. Your cylinder seals are good, but maybe there's a leak from a water passage into an oil return passage.

 

[jabfd]

Re: 470. Oil coming from valve breather tube

Would that cause oil to come out of the valve cover and is there another test to check the head gasket ? Thank you for your help

 

[Another retired guy]

Re: 470. Oil coming from valve breather tube

Would that cause oil to come out of the valve cover and is there another test to check the head gasket ? Thank you for your help

Yes. The water mixes with the oil and the level in the oil pan increases to the point where the crankshaft starts splashing into it. This creates foam which will make its way up the oil return passages into the valve cover and out the vent tube. Engine heat will then evaporate the water in the foam leaving only the oily residue on the engine.

I don't think there is any test for this

 

[jabfd]

Re: 470. Oil coming from valve breather tube

Ok should I try a oil change and see if it happens again . If I take the head off will I see the damaged gasket . Can I replace the just the gasket .or is there something else I need to do .

 

[Another retired guy]

Re: 470. Oil coming from valve breather tube

Ok should I try a oil change and see if it happens again . If I take the head off will I see the damaged gasket . Can I replace the just the gasket .or is there something else I need to do .

At this point everything is just speculation. Changing the oil "may" be a waste of money, but it would help to confirm that this was not some form of "one-time" event.
If there is a leak it may not be obvious when the head is removed.
Has the engine overheated at all recently? While the head is off it should be checked to make sure it isn't warped.
I believe the 470 has an aluminum head? and it is fairly common to have problems when mating aluminum to iron
Follow torque instructions in the manual very carefully!

Edit. I may have that backwards? Aluminum block with iron head? Not sure!

 

[wrestling coach]

Re: 470. Oil coming from valve breather tube

FWIW 470's have aluminum BLOCKS, IRON 460 Ford heads.

I would attribute the milky oil in the breather to condensation. I don't know how you use your boat but if you don't operate any engine for some extended time at full operating temp and speed it has a hard time getting the moisture out of the crankcase and associated parts. I would only keep a watch on your coolant level and oil level for now. I would make some long runs at higher speeds and get the ENGINE, not just the temp gauge, fully up to temperature. Your oil filler cap should be wiped clean and watch it for the telltale results.

Dennis

 

[jabfd]

Re: 470. Oil coming from valve breather tube

At this point everything is just speculation. Changing the oil "may" be a waste of money, but it would help to confirm that this was not some form of "one-time" event.
If there is a leak it may not be obvious when the head is removed.
Has the engine overheated at all recently? While the head is off it should be checked to make sure it isn't warped.
I believe the 470 has an aluminum head? and it is fairly common to have problems when mating aluminum to iron
Follow torque instructions in the manual very carefully!

Edit. I may have that backwards? Aluminum block with iron head? Not sure!

Engine never over heated changed the oil took it for a two hour ride and came back and had a problem

 

[Another retired guy]

Re: 470. Oil coming from valve breather tube

I considered condensation, but it sounds like too much foam being produced - it's in the oil pan, valve cover, and flowing down the engine

 

[jabfd]

Re: 470. Oil coming from valve breather tube

I considered condensation, but it sounds like too much foam being produced - it's in the oil pan, valve cover, and flowing down the engine

Ian going to change oil and see if the problem happens again I hope not ! But if it does . could it be something else or is the headgasket the only thing that could cause it thanks

 

[Another retired guy]

Re: 470. Oil coming from valve breather tube

Ian going to change oil and see if the problem happens again I hope not ! But if it does . could it be something else or is the headgasket the only thing that could cause it thanks

I also hope it was just one of those strange one-time things
If it is water getting in the oil, there is one other way but I was hoping you wouldn't ask
It's unlikely in your case, more likely if this was a winterization problem, and that is a cracked block

Another way to tell if it is water is to keep a close watch on your coolant level. You have a closed system, so any water getting into the oil would lower the coolant level.

 

[stonyloam]

Re: 470. Oil coming from valve breather tube

Wait a minute here! Is there water (coolant) in the crankcase oil? Is it milky or does it look like normal oil? If the crankcase oil looks good than it is doubtful you have a headgasket leak.