oil coming out of dipstick at high rpms??

[peanutbay1]

Problem;
My 1990 5.7 mercruiser is intermitanly pushing oil out the dipstick at 4000+rpm range.

Background:
This boat was sitting for 3 years in a boat yard. We got her 6 weeks ago and have been bringing her back to life since. We had moisture in the oil which in the end proved to be a failed thermostat causing severly cool conditions in the engine thus forming condensation. We have 5 runs on her and every run we have an overflow of oil out the dipstick (maybe several tablespoons). This engine passed compression,leak down and vacuum tests and the boat runs like a top.

Questions:
1) Is there any type of crankcase vent that could be blocked??
2) Does the fact that this is intermitant tell anything???

Please help!!!!!!

 

[zbnutcase]

Re: oil coming out of dipstick at high rpms??

Assuming there is no probs with engine (as in cracked block or heads, or head gasket issue) all the moisture in it will evaporate when it gets warm. If continues to do it you have an issue somewhere. And an engine can pass every test known to man and run great and still have a cracked block. 'nutcase

 

[peanutbay1]

Re: oil coming out of dipstick at high rpms??

Mabye I need to ask some different questions.

How is the crank case vented to not build up pressure??
If your dipstick is at the high side of full could it push oil??

 

[peanutbay1]

Dipstick question??

Dipstick question??

1990 5.7 mercruiser

My dipstick is leaking oil out the finger loop tube. Is this supposed to be sealed??? Could there be a cap on the end of the tube that is missing??

 

[ErieRon]

Re: oil coming out of dipstick at high rpms??

I don't know about the "vent" question, but it seems to me there wouldn't be one. The fit of the fill cap and dipstick certainly aren't designed for high pressure sealing. I think the pressure is regulated in the pump only and then circulated through the engine.

If your over filled, I can see it coming up the dipstick tube. There's not a lot of volume in that little tube, so a little would act like a lot. Why don't you draw some out, to the correct level, and give it a go.

 

[ErieRon]

Re: Dipstick question??

Re: Dipstick question??

1990 5.7 mercruiser

My dipstick is leaking oil out the finger loop tube. Is this supposed to be sealed??? Could there be a cap on the end of the tube that is missing??

Ahhh, the old finger-loop-tube oil leak

It shouldn't be leaking. Make sure the dip stick is fully seated when returned. It should sort of snap/pop in to create a seal on the rubber boot inside the cap. Make sure the oil is not over full. If it still leaks, replace it, eh?

 

[Aviator5]

Re: oil coming out of dipstick at high rpms??

A tubes going from each valve cover to spark arrestor are your crankcase vents. Overfill won't push it up the dipstick tube.

 

[tfret]

Re: oil coming out of dipstick at high rpms??

I had the same problem once. The vent hoses that run from the valve covers to the spark arrestor were clogged. This caused a build up of crank case pressure which took the path of least resistance up and out the dip stick tube. Cleaned my vent hoses and have never seen the problem since.

 

[jtybt]

Re: oil coming out of dipstick at high rpms??

I agree with tfret. Check vent at valve covers first.

It's a case of excess crankcase pressure build-up. If it's not a clogged vent, the problem may be more serious.

 

[Gomer50]

Re: oil coming out of dipstick at high rpms??

I dont want to sound negative but in my experience oil coming out of the dip stick is because of excess amount of pressure in the crank case meaning possible blow by which is not a good sign.Start motor pull the dip stick and put your finger on the dip stick tube and see if there is any real noticeable pressure there.Possible head gasket, piston rings valve guides.Or as suggested above see if valve covers have ventilation.

 

[peanutbay1]

Re: oil coming out of dipstick at high rpms??

I need to give more details. This is not all the time. We ran the boat on sunday for an hour straight with no oil at all. Then after a short break we ran again and it pushed about 2 table spoons. Stopped again for 15 minutes and ran another 1/2 hour with no oil. This problem is consistant in the sense of each trip it has done it at least 1 time at higher rpms but through out each day of running it was an intermitant event.

 

[Don S]

Re: oil coming out of dipstick at high rpms??

Does your engine have a PCV valve in the valve cover? Is it supposed to? Many had just an elbow.
If it's supposed to have an elbow and someone stuck a PCV valve in it, that could be your problem.

 

[EddiePetty]

Re: oil coming out of dipstick at high rpms??

...... This problem is consistant in the sense of each trip it has done it at least 1 time at higher rpms but through out each day of running it was an intermitant event.

....just a little different angle here, as you have already done a leak-down test (which should have eliminated excessive blow-by).
What's the chance that either a) the dipstick is in the tube 'backwards', b) the crimp (or o-ring) around the dipstick handle does not fit the tube tightly, or c) the dipstick is ejected after a hard turn (caused by an oil splash resultant in either a) or b) ????

...just a SWAG, Ed in 'ol Virginny

 

[Bondo]

Re: Dipstick question??

Re: Dipstick question??

My dipstick is leaking oil out the finger loop tube.

Ayuh,... I searched,+ Searched,.... I can't find anything called That....

If the Dipstick tube is blowing oil,...
If might be Over-full, like Ron says,...
Or,...
You could be experiencing serious Blow-by,...
Or, the crankcase Vent might be plugged...

Even if it were an O-ringed dipstick,+ the o-rings were Gone,...
It shouldn't be blowin' oil....

 

[Knightgang]

Re: Dipstick question??

Re: Dipstick question??

I bet the crankcase vent it plugged up....

 

[EddiePetty]

Re: Dipstick question??

Re: Dipstick question??

1990 5.7 mercruiser

My dipstick is leaking oil out the finger loop tube.

...I believe you are referring to the curved, tubular, finger-hole on the DRY in of the dipstick.
If so, most of that type that I have seen are either crimped closed or have a plastic plug in the end.
In either case, seal with your favorite sealant and THEN locate the cause of either excessive oil level and/or crankcase pressure.

FWIW...Ed in 'ol Virginny

 

[Bondo]

Re: oil coming out of dipstick at high rpms??

Ayuh,.... Why are there 2 threads about this Same issue....

I posted in your Other thread,....
About the Finger Loop Tube....

 

[havasuboatman]

Re: oil coming out of dipstick at high rpms??

All motors have a cretain amount of piston blow by. The older an engine gets, the more blow by. Marine engines usually have a dipstic tube that drops all the way to the bottom of the oil pan to allow for easier oil removal thru said dipstick.
Look at you valve covers. There should be vent tubes that run from the valve cover to the spark arrestor. Make sure these are not clogged. Yours probably are because you said you had some water in your oil. Heat will steam it out, but in doing so it tends to clog the hoses that are for venting purposes. If you have a PCV valve, Remove it. Your boat shouldn't have one.

 

[ErieRon]

Re: oil coming out of dipstick at high rpms??

Believe it or not, I think this is the second, legitimate finger-loop-tube oil leak thread...

EDIT: OK...maybe not...what's up with that...

 

[Don S]

Re: oil coming out of dipstick at high rpms??

Ayuh,.... Why are there 2 threads about this Same issue....

I posted in your Other thread,....
About the Finger Loop Tube....

Both threads are now in this one thread. Now all the info is in one place, not two.