Harper220

I really don't have any decent Mercury Marine mechanics in my area, so I thought this would be something I could tackle. I'm somewhat mechanically inclined, so I'd like to learn to do some of these things on my own. I could probably figure out how to remove the heat exchanger, but would like to hear from the pros how to do it most effectively?

Wally

iTrader: (1)

Just out of curiosity....has anyone had any problems yet in the boating community with the orange antifreeze? I know that ALOT of the guys on the GM forums i visit have switched out the dexcool Or "deathcool" as they call it cause if the system get some air in it the stuff starts to sludge and will block the cooling passages!!! I'm not talking about just a little air exposure but letting the level drop enough that it gets into the radiator etc.....
I changed mine out on my 96 yukon when i did the water pump cause it was showing signs of sludging when i pulled off the pump!! And i am anal about keeping levels right! Maybe it was the previous owner i dont kow but i didnt want to take any chances!

Gizmo

Wally, I had the same issue with my girlfriends Jimmy. Coolant got low and turned to sludge. Even the heater hoses got plugged. I drained the system, flushed with clear water, several times, added a system cleaner, drained and flushed some more, then refilled with new dex. Now, it seems to be happening again. This time (after it is clean) I will use regular anti-freeze.

Bill 3

Harper220

I replaced the grommets on one motor this spring for this problem exactly. I had both motors out over the winter and so my bilge was sparkling and after the first time out this spring I noticed pink water in the bilge and traced it down to these grommets. I did not know anything about asking merc to pony up for the grommets, I just bought new ones. They are about $7 each. They are not hard to replace, but you will get a lot more antifreeze in the bilge. I believe there are 3 hoses you will need to remove from the heat exchanger and the 2 big hose clamps that hold the heat exchanger in place. Once it is loose, rock the exchanger back and forth as you pull up. Put a little grease on the new grommets when installing them and put everything back together.

The first step would be to make sure there is antifreeze in the bilge and that this is for sure your problem. I would imagine it is. You could also take a clean paper towel and wipe it around where the grommets are sealing and see what you come up with.

Hope this helps,
Bill

Harper220

Thanks Bill, this helps a lot. It sounds like I can handle this one...

Dave M

I just had a 496 installed in Feb and I noticed a few drops of coolant in the bilge but not the whole reservoir. Maybe the temps are not as extreme in my locale.

Harper220

Ok, here goes.. I just finished pushing, pulling and cussing to finally get the heat exchanger off. I pulled both grommets out and completely cleaned them up as the one on the left had a little white scale build up. I put everything back together and filled the reservoir back up with dex-cool and here it comes again, except I think it was coming out of the little hex plug on the left just below the large hose that goes into the bottom of the heat exchanger. So I pulled everything back apart and removed the plug and found that it has a ton of scale and lime build up. Could this be the only other place it's leaking from? It was very tough to see up in there, but I'm pretty sure that's where the leak stemmed from. When I removed the plug, of course all the coolant came out. I'm going to clean up the plug and teflon tape it. Anybody else have any other ideas? Cuz, so far this has really sucked chasing a little leak... I've got about 3 hours into it so far.

PatBrennan

I had this identical problem with my 2003 496 Mag HO, after winter storage the Anti Freeze tank was always a quart or two low. After reading this forum string I ordered a new pair of grommets (I couldn't tell for sure that it was leaking from there, but for a few bucks thought I'd give it a try. The replacement part number is 26-865066, they were $7.85 each. I compared them to the old units and they are indeed different. There is a molded o-ring on the outside of both grommets but the new ones the o-ring was much thicker than the old ones. I installed them and will have to wait until next winter to see if they fix things.

fyi,

Tantrum

You want my professional drinking opinion on this

Rippem

exactly! same program here. Only my port leaked down...2 winters in a row, and definitely redesigned with the embossed o-ring effect on the new part#