Oil Change Maintanance- Blown Head Gasket?

[trdexpert]

Hey Guys, Im going out to the lake this weekend but I want to do an oil change on the engine before going out.

I have an 1979 OMC v8 185, What type of oil is recommended for this engine.?? It has 769 hours on it.

I also noticed clear milky goldish oil on the dipstick, does that mean I have a blown head gasket? It sat for 10yrs, or could it be just old oil that has been sitting for years or water when in the engine some other way..??

Thanks!


Thank

 

[bigman8u4lunch]

Re: Oil Change Maintanance- Blown Head Gasket?

to answer the first question a marine grade 10w-30 would be fine. As to the second question it could be a number of things... i would go shotgun method on this, I would change the oil, then run it at home with water hooked up to it and pull the valve covers (look in oil fill hole or check dipstick again) after about 5-10 minutes. If you get icecream it could be anything from a craked block, bad headgasket, or craked intake manifold, in which case i would pull it and overhaul

 

[Howard Sterndrive]

Re: Oil Change Maintanance- Blown Head Gasket?

three recommended oils
straight 30 weight
20W50
25W40

nothing beginning with a number lower than 20 for a marine engine with no oil cooler (and OMC never used oil coolers)

grow very long arms, and loosen the fitting at the bottom of the dipstick tube to drain the bottom of the oil pan and see what comes out before putting any money into a boat with a potentially cracked block

if water comes out- you need to pressurize the cooling system

 

[bigman8u4lunch]

Re: Oil Change Maintanance- Blown Head Gasket?

three recommended oils
straight 30 weight
20W50
25W40

nothing beginning with a number lower than 20 for a marine engine with no oil cooler (and OMC never used oil coolers)

grow very long arms, and loosen the fitting at the bottom of the dipstick tube to drain the bottom of the oil pan and see what comes out before putting any money into a boat with a potentially cracked block

if water comes out- you need to pressurize the cooling system

Not trying to thread jack. Could you clarify why? i was told 10w-30 from the maintinence shop I frequent. thank you. I dont want to mis inform.

 

[Howard Sterndrive]

Re: Oil Change Maintanance- Blown Head Gasket?

10W is too thin unless you boat in very cold ambient temps (e.g. Arctic Ocean)
10W30 fine for Volvo Penta engines with an oil cooler, but not OMC

I recommend consulting an OMC manual . All fluid specs are in the manual. even the aftermarket manuals are pretty good with recommended fluids

769 hours is also quite a bit for pleasure boat motor - don't want oil in there that is too thin

 

[bigman8u4lunch]

Re: Oil Change Maintanance- Blown Head Gasket?

I went and found one for my engine, wish I did earlier. Has a chart and confirms, thanks a bunch.