View Full Version : Closed Cooling System Overheating Issues

01-03-2009, 11:16 PM
For those of you who have some overheating issues with you closed cooling system. Check the following. You closed cooling system can develop an air void in the block. This is indicated by: when engine is overheated and you idle up to 1200-1500 rpms the engine would then cool down. Also, same circumstance and you idle up to cool then engine you must refill the system with a mix of 50/50 water and coolant. Most of the boats down here by me have closed cooling because they are all saltwater boats. For some reason I seem to be the guy they call when they are stuck out on the water with something going wrong. Nonetheless I found that these guys were refilling with straight coolant, which will lead to overheating in its self. Be sure to mix 50/50...Also to burp the system, rev engine to 1200-1500 rpm start with engine is cool so you can get the cap off without getting burned or wet. While revving the engine squeeze all the closed cooling hoses, watch the coolant overflow bottle, you should see some bubbles and burps coming through. Hope this helps anybody. MCX and Crusader Motors. www.waterskimarcoisland.com