Anti Freeze lost

doozie

Active Member
GOLD Sponsor
Dec 6, 2007
553
MIDDLE RIVE MD.
Boat Info
46 sundancer 2001
Engines
3126B 450hp Cats
Hi all, It seems after about 6 hours of running this year, I need to keep adding anti freeze to the port motor, about 16 ounces so far, It's doesn"t appear to going into the engine, just had Cat at the boat to do the valve adj. no ssgn of problems. Engineas are 3126B 350 hours, Any thoughts of were to check, starboard motor has been fine, both run at correct temp. Thanks Bob
 
I have not, naturally that would be the hardest one to get at and i"m guessing the only way to check is to remove it and have it pressure tested? Bob
 
You can pressure test the cooling system without pulling it apart, just pump it up (or have your mechanic do it) and see if it holds pressure without dropping.
I had a similar problem, turned out to be the cap on the stbd. motor. The pressure test held fine whcih meant the cap had to be the culprit. That's also a simple one to rule out- pull both caps off the expansion tanks, top them off if necessary, then switch caps. If your stbd engine loses coolant instead of the port after running- you solved the problem.
 
Ok, update, I pulled the tube assembly, cleaned, replaced all the gaskets and it is still leaking. it only leaks after running the engine then it seems to leak as it cools. we could not see any problem with the tubes, but guess it could have a small leak. Any thoughts before I replace the assembly to the tune of 1,400. Thanks Bob
 
Could be a head gasket. NAPA sells a tester (think it's called a block tester) for this that you use on the heat exchanger. It checks for signs of exhaust in the antifreeze while the engine is running at normal operating temperature. Easy to do, kit is around $50 if I recall. It's a long tub, almost like a turkey baster, with a rubber end that fits over the radiator cap opening.

Confirmed the source of our antifreeze leak last year. Ours turned out to be the exhaust manifold. Not sure if this kit works with diesels, assume it would.

Here is an article on this: http://www.arrowheadradiator.com/head_gasket_or_combustion_leak_test.htm
 
Last edited:
Problem resolved, took the end cap off the heat exchanger, bolted the tube assembly back in tight, pressurized the system, leak was in a couple of the tubes. New tube assembly ordered. Thanks Bob
 

Forum statistics

Threads
112,948
Messages
1,422,805
Members
60,930
Latest member
Ebrown69
Back
Top