Anti-freeze leaking from 496
03-11-2004, 01:39 PM
#12
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Hey, Hopefully some good news.....I had a 2001 with twin 496 MAG's and had the same problem. Took it back to the dealer and Mercruiser said the problem was due to the seals shrinking in extremely cold weather and the seals would re-seat themselves when the weather warms above 30 F. (he gave me a gallon of antifreeze)Mine leaked about a pint for each engine for two winters. Never had a problem in the summer. I flushed the bilge and forgot about it. Suppose you could get mercrusier to replace the seals but the main thing is it's not a major problem like a cracked block,etc). I did my own winterizing so I know the sea water side was drained and flushed with coolant. I've since traded the boat in for one with 496 HO's and wonder if it will have the same problem.
03-11-2004, 03:00 PM
#13
Bajabouy,
I have 2002 HO's.
Summer 2002 no problem
Winter 2002/2003 no problem
Summer 2003 no problem
Winter 2003/2004 both engines have leaked about 1/3 of the tank.
I went to Merc microfich and those seals on the bottom of the heat exchanger changed part numbers. I wonder if the reason the part changed was to improve/solve this problem.
Does anyone know if this is true????
Rick
I have 2002 HO's.
Summer 2002 no problem
Winter 2002/2003 no problem
Summer 2003 no problem
Winter 2003/2004 both engines have leaked about 1/3 of the tank.
I went to Merc microfich and those seals on the bottom of the heat exchanger changed part numbers. I wonder if the reason the part changed was to improve/solve this problem.
Does anyone know if this is true????
Rick
03-11-2004, 04:25 PM
#14
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I went ahead and changed the two seals between the heat exchanger and the crossover. The seals looked fine so I hope that fixed it. Mine must have also leaked last winter because I found anti-freeze in the bilge but could'nt find were it came from. Didn't have any problems all summer.
03-12-2004, 07:30 AM
#16
Nofed,
Did you get any insight from your dealer on this or did you just go ahead and replace them yourself? If you did it yourself, how bad of a job was it, any problem areas?
Bajabouy,
'getting ansi for spring' me too!
Rick
Did you get any insight from your dealer on this or did you just go ahead and replace them yourself? If you did it yourself, how bad of a job was it, any problem areas?
Bajabouy,
'getting ansi for spring' me too!
Rick
03-12-2004, 04:34 PM
#17
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I did'nt contact the dealer. I just went onto the Mercury Marine web site and checked out the closed cooling section on the 496. It was pretty easy to change the seals. All you do is loosen the 2 clamps that hold the heat exchanger to the crossover and pry it up VERY carefully. It should just pop up off the seals without taking any of the hoses loose. It takes a little patience to get the seals out and in , but all in all it was pretty simple.
05-16-2004, 07:44 PM
#20
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Re: Anti-freeze leaking from 496
anybody having any more experience with this? I went over today to put the batts in and low and behold...port coolant res. empty! 
Two quarts or so in the bilge. If it's a severe cold problem with the seal (it was -20 to -40 here for 3 weeks this winter) why didn't both leak down? Is there, or is there not a service bulletin on this?? 
Do I just fill the reservoir back up and forget it? Take it for granted it wont leak in warmer ambient temps?
Two quarts or so in the bilge. If it's a severe cold problem with the seal (it was -20 to -40 here for 3 weeks this winter) why didn't both leak down? Is there, or is there not a service bulletin on this?? Do I just fill the reservoir back up and forget it? Take it for granted it wont leak in warmer ambient temps?
