Sydwayz

iTrader: (1)

Nothing wrong with 496HOs. I love mine and know plenty more who do.

The air pump system is NOT sufficient for winterizing, especially in a really cold climate. You MUST winterize it the old fashioned way by running antifreeze through the sea water side of the cooling system. The sea water side of the cooling system will absolutely hold pockets of water in it by only using the air pump to push out water. The air pump system is only good enough for marginal temps to extend your boating season.

Raylar

HOBoater:

Sounds like you may have just had a failure in the factory stock head gasket, but it could also be a crack in the head, so isolate which it is. Raylar has stock new takeoff iron heads in stock and we have our 496 Raylar/Cometic MLS stainless head gaskets in stock as well as any other 496 parts you might need. We can give you some tips on how to properly clean the coolant from your motor and make sure you have a clean, water free crankcase as well as methods for checking the seal up after you reassemble. Call Raylar toll free @ (866) 496-8181 M-F Pacific time if you need parts and assistance.

Best Regards,
Ray @ Raylar

launchpad475

iTrader: (1)

yikes, sounds like I have the same problem. Just added a bunch of anti freeze, ran it for a day and it's low again. Not a winter problem I don't think, I've put 100 hours on this thing this summer at least.

I'll have to keep an eye on it.

TWIN-SPINS

pressure test the coolant system first,,might just be a small leak,,,

Griff

If there is AF in the oil, its going to eat the bearings real fast.

launchpad475

iTrader: (1)

what does oil look like with anti-freeze in it? Dipstick looks pretty normal.

GO4BROKE

iTrader: (1)

If it has been run, it will look like baby diahrea.
Not run it will stay seperate.

Raylar

Believe it or not on the Mercrusier 496's, the dipsticks only go into the oil fitting at the bottom of the pan and run up along the side out of the engine so we have seen 496's with 2 -3 quarts of dex-cool in the crankcase that would not even show up on the dipstick until it was way to late!!
If you've got coolant in the oil, do not run the engine, drain the oil, pressure test the coolant system and find the leak. If the block is cracked its already over for the internals.
If its just a minor or moderate leak, find the leaking head gasket or cracked head or oil cooler leak and fix it right away! and then you can flush the oil system with oil and dexron mix and change the filter and refill with fresh oil, run the engine lightly for a few hours and then re-change the oil and filter until no more oil contamination shows in the filter and cooler. If you are real lucky and you catch it in time and your oil pressure runs at normal ranges and your filter, cut open shows no metal debris you might just be damn lucky!! Hope you become Damn Lucky!

Best Regards,
Ray @ Raylar

launchpad475

iTrader: (1)

Thanks for the responses, I have a couple questions. Does the 496 have alum heads? The oil gets dirty pretty fast, I've seen alum heads do this to oil.

Or, it could just mix real fast with the oil that doesn't get sucked out and looks kinda dirty sooner than normal.

Once I get the oil out, is there a way to check besides the baby puke method? Maybe it's not sucking it out, the antifreeze part.

I put about 1/3 of a gallon into the reservoir recently, and it is reading low again. Hope it's not too late, but at least its the end of the season.

Any advice on pressure checking the system?

Thanks-

plowboy

Are you saying the closed side(engine block and heads) should have 100% dexcool instead of 50/50 mix??? The merc manual says it should be a 50/50 mix of extended a/f and distilled water.