View Full Version : Loosing coolant

Don Brown
07-10-2008, 08:25 PM
"Have 350 yanmar that is loosing coolant each time used. Engine does not overheat(unless at wot) but after cooling down coolant is low, up to one and one half gallons after 2-3 hours of use.
Any ideas?"

07-11-2008, 08:21 AM
I would think you have a 6LY model? Check the intercooler and the exhaust manifold. You will have to emove and presure test. Always use a long life silica free coolant. Dexcool or a Texico full mix long life coolant.

03-22-2010, 07:33 PM
"My problems have increased. Still loosing coolant. Also overheating at less than wot.
How do I check the intercooler or pressure test the exhaust manifold. Do I need to flush anything, if so, how? Where, and what is, the build up that clogs the coolant system?

03-23-2010, 08:16 AM
It sound slike you have a bad heat exchanger to me. It sounds like one or more of the tubes have rutptured and leaking coolant into the raw water flow and being washed out the exhaust.

You can remove it and take it to a radiator shop (that has the proper equipment) for rodding out and pressure testing.

06-25-2015, 06:08 AM
Just reading though some of the posts here and I am interested in any charge air cooler/heat exchanger issues that arise. I work for a company called Vestas aircoil who manufacture and design charge air coolers for large diesel engines typically for ships/vessels. I think it is known to block some of the leaking tubes to temporarily fix the problem but is n quick fix.