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Water leaks - Rubber seals

dwleo

New member
Hi all,
Newbie here running into a brick wall with my boat.
I have an AQ170C in-line 6 cylinder with 280 drive. I recently acquired this boat and was warned about overheating. I removed the intake/exhaust manifold and ensured it was clear in the water jackets. I replaced the circulating water pump and, after also replacing some corroded wiring got it fired up. Ran great but as I watched the temp gauge, it was rising very quickly. I also had some water leaks where the various coolant pipes fitted into the water pump and the exhaust manifold. I had replaced these with new seals but still leaked. Also saw leaks at the thermostat housing where it joins through to the waterpump.
So, I fixed the overheating (thanks to a tip on this forum that worked extremely well) but am problemed by these rubber seals and getting them to seal. Also in my manual it states that when replacing the thermostat and rubber seal, the thermostat MUST be installed with the seal against the block. I also have an exploded view which shows the thermostat against the block.

5104.jpgthermostat.jpg
Which is correct?

I cannot, for the life of me, get the seals to seal where the water pump attaches.
All in all, of the over 8 rubber sealing rings, only two are actually sealing. I suspect this is by dumb luck only. Is there a great, huge secret to properly install these rings? Should I use a compound with them? I have had these on and off several times and have replaced them numerous times without success.
I would appreciate any and all help.
Thank you.

- Daryl
 
Daryl, After working on these older engines for many years, I myself, use a very slight amount of silicone on them and then let it dry for a day or two before testing it. Over the years and after many folks working on them, these old iron headed engines have been beat on or heated up and the copper pipes just aren't the same as they were new. A slight bend in any of all those pipes and it will leak. The silicone will work wonders, just don't go for the old "a little more is better" angle. Silicone in the cooling system is not a good thing.
 
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