1985 2.5 motor has water in oil

i am looking at a 1985 17.5 ft boat with 2.5. boat has been sitting two years. i checked the oil and it is overfull and milky. should i change the oil and run the engine? if the engine is leaking where is the most lickly place to look

Re: 1985 2.5 motor has water in oil

dmead000 said:

i am looking at a 1985 17.5 ft boat with 2.5. boat has been sitting two years. i checked the oil and it is overfull and milky. should i change the oil and run the engine? if the engine is leaking where is the most lickly place to look

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Ayuh,.... Welcome Aboard,... It's got a Cracked block, 'n needs, atleast a new motor...

Re: 1985 2.5 motor has water in oil

Well I don't know much about boats and there motors, but when it comes to car engines especially classic mustang 302 motors, milky oil generally means blown head gasket. I wouldn't say cracked block yet, but that is just my two cents and I could be wrong. Pull the valve covers and then heads, check head gaskets for signs of cracks or missing pieces, damaged. You may be in luck, as for oil over filled though maybe that is indication of cracked block. At this point you can't really go wrong checking unless its not your boat yet.

Re: 1985 2.5 motor has water in oil

And when you mention your looking at then I assume its not your boat. Ask owner if you can remove heads and see what he says though. If he wants it gone then good chance he will say yes. Post pictures when you can.

Re: 1985 2.5 motor has water in oil

Well I don't know much about boats and there motors, but when it comes to car engines especially classic mustang 302 motors, milky oil generally means blown head gasket. I wouldn't say cracked block yet,

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Milky oil and over filled sump generally means a cracked block in a marine engine.......and it's usually due to poor or no winterization..... "Blown" head gaskets are not a frequent problem. The original posters engine is a 2.5L 4cyl.

Re: 1985 2.5 motor has water in oil

That's good to know.......as like I said I know nothing about marine engines. Learning as much as I can but only telling it how it is with a auto gasoline engine. Keep my two cents to myself then
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Re: 1985 2.5 motor has water in oil

thanks . where is the most likely to look for crack the head or the block?

Re: 1985 2.5 motor has water in oil

dmead000 said:

thanks . where is the most likely to look for crack the head or the block?

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Right below the intake/exhaust manifold on the block. Between the blow out plugs. I would close off cooling system and pressure test it.

Re: 1985 2.5 motor has water in oil

dmead000 said:

thanks . where is the most likely to look for crack the head or the block?

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It's as frequently internal as external. The best way to find a block crack is to pressurize the block and head with about 15 psi air pressure.

Remove the riser and manifold and treat the long block like a pressure vessel with multiple, different size openings.

Plug all the openings except 2, using whatever plumbing fittings and hoses and you can scrounge from your favourite home center.

Connect a 0-30 psi gage to one of them and a valve + air hose to the other. (or connect the gage on the engine side of the valve)

Apply about 15 psi with your compressor (turn it off so you can hear) and close the valve.

Look at the gage and listen for leaks. If the gage "drops" it's leaking some place.....

If you have a leak on the outside and you cannot identify where, use a little soapy water. If it's internal, you'll hear it in the oil fill tube.

water in the oil is almost always due to internal cracks.

Blocks usually crack more frequently than heads because the head is above the block and it somewhat drained of water which will usually pool in the block since it's the lowest (internal) point in the cooling system. This is why there's block drains (petcocks, pipe-plugs etc) on the side of the block.

Re: 1985 2.5 motor has water in oil

thanks for all the help