Mercruiser Closed Cooling Installation Tip for Old Engines

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Topic: Marine Engine Cooling System Installation Tip's

Question #1: Can I install a new Closed Cooling system on an old engine? I've heard that the antifreeze will "Gel" due to a reaction with the salt and cause the system to somehow plug up.

Response #1: Although the potential might exist for this to happen our experience and extensive testing has shown this is a situation where the reality is not nearly as severe as the concern. We have sold or installed hundreds of systems on older engines since the late 1990's. To date we've never had a single case where the effect was dramatic enough that it prevented the system from functioning normally for the purpose it was originally installed; to cool and protect the engine. At the same time we acknowledge the fact that many people are convinced this is a major issue and WILL cause engine problems. Therefore we strongly encourage installing the closed systems on older engines for the intended purpose and benefits they provide.

Here are a few additional installation tips we've found to be very helpful when installing a closed system on a previously operated engine.

Flush out the engine by forcing water through the intake manifold thermostat seat, allowing it to flow out the engine circulating pump inlet.
Install the cooling system but do no assemble the thermostat. Instead take a small pair of panty hose and cut off the foot to make a small "Sock" type of debris filter. Insert this sock/filter into the hose fitting where the hose connects that normally allows for coolant to flow up out of the thermostat before re-entering the heat exchanger.
Following the normal system fill instructions, fill the system with tap water.
Run the engine on a water hose for a minimum of 30 minutes (not exceeding 2,000 rpm), then allow then engine to cool.
Drain and remove the "Sock" filter and discard along with any debris.
Insert the thermostat as specified in the instructions.
Fill with antifreeze mixture per the supplied cooling system instructions.

NOTE: If you are still convinced this is topic is an issue and area for concern we recommend following the above procedure while flushing the system out with "Salt Away" to ensure maximum removal of existing salt buildup.

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