Head Gasket / Milky Oil

[Jon1229]

hi,

boat is running fine but there is an air leak I can’t pinpoint it. When it runs it is loud. I did a compression test and have 150 in all 4 cylinders (2001 mercruiser 3.0). If I have full compression it isn’t a head gasket (based on what I know, but I don’t know that much), so I was thinking it could be the gasket between the head and the exhaust manifold? this is where it is. It comes from underneath the manifold next to cylinder 1, I just don’t have a better angle.

 

[TyeeMan]

When you say "air leak" what exactly do you mean? If you hear something like a pop, pop, pop you could have an exhaust gasket leaking. As in the gasket between the exhaust manifold and head. Pretty easy fix.
Mix up some dish detergent and water, drizzle that in the area you suspect your air leak. If it's leaking it will bubble like crazy.
If you are hearing a hissing, like vacuum, you can find that leak fairly easily with a can of carb cleaner.

I agree, I think your head gasket is fine especially if your getting 150 in all 4 cylinders.

 

[Bt Doctur]

hearing anything like a hole in a muffler is a exaust manifold leak

 

[Jon1229]

Thanks, yeah it’s a pop pop pop that pops more rapidly as I increase the rpms.

 

[Bt Doctur]

depending on your serial number I would use 27-96429

 

[Jon1229]

Chronic head gasket

Okay so the head gasket blew once, we replaced it. It blew again and we dove deeper and found the Block was 0.015 off and head was 0019. I had the engine worked on by a machine shop and put it back together with a new gasket. Now, it has blown a third time in 3 weeks.. what could be causing this?? It’s a 2001 mercruiser 3.0 on a Monterey edge 180 bowrider.

 

[Searay240sd]

What head gasket are you using? Are you using new head bolts. Are you following the right torque sequence? What are you using to torque the bolts?

 

[Scott Danforth]

Overheat/over RPM is the number one reason.

Will also .Aks what gaskets and head bolts?

What is your WOT RPM

 

[Bt Doctur]

timing set to ????????????? Anything from 1 BTDC or more will blow the gaskets Standard is zero ,1 ATDC or 2ATDC

 

[Jon1229]

I did not replace the head bolts, I reused the stock ones both times. The gasket I’m using is a Sierra for the 4 cyl mercruiser engines. I’m using a torque wrench and following the sequence in the diagram starting from middle working outward alternating sides. I want to say wot my rpms Are just under 5000. Maybe like 4800. Every time it blew I was going very very close to full throttle.

 

[stonyloam]

Where is it blowing. Between two cylinders?

 

[Jon1229]

Where is it blowing. Between two cylinders?

No it is blowing out of the side of cylinder 3

 

[Jon1229]

[No message]

 

[Searay240sd]

What do your plugs look like, do you have the rights one in? Also what is your base timing and full timing at?

 

[Jon1229]

What do your plugs look like, do you have the rights one in? Also what is your base timing and full timing at?

All 4 plugs are brand new I replaced them after the first blown gasket. I replaced them with the same type that was previously in there, so I think they’re the right ones but i guess it could be possible that they weren’t the right ones in the first place. As for the timing I don’t know how to figure that out so I couldn’t tell you unfortunately

 

[Bt Doctur]

you paint a white line on the balancer at the notch and use a timing light.

 

[Bt Doctur]

you did say number 3 cylinder, right

 

[scoflaw]

The 2 surfaces are not flat enough

 

[stonyloam]

You could use a machine file draw filing the top of the block to see if there is a low spot. There is a good little video on you tube.

 

[Jon1229]

you did say number 3 cylinder, right

Yes exactly this