View Full Version : Volvo AQ131D Antifreeze in bildge

09-07-2006, 04:33 PM
"I have a AQ131D with approx 235 hours / much more than half in fresh water. Recently replaced the Sea water strainer unit(the bake-a-lite blew apart at the screws holding the elbow). Ran in the lake for approx 1 hour trouble free. Ran in the river for approx 1 hr. and 5 mins. at steady +/- 4,000 rpms. Ran normal for an hour and five mins. (200F). Then began to climb very quickly and in just a couple of mins was at 225F and I shut down. After cooling I restarted and with cover off the strainer and it pumped water out. After being towed back to the dock and putting boat on trailer I pulled the}}} plug and found that all the antifreeze was in the bildge. Intercooler cap feels loose to me - not like on a car radiator - is this normal for the cap. Any suggestions what might have happened after an hour of steady running at "normal temp" to cause all the anti-freeze to be in the bildge?"

El Pescador
09-07-2006, 11:10 PM
Is your alternator belt loose?

09-08-2006, 07:10 AM
First - El Pescador THANKS for such a quick responce! I don't think that the belt is loose as the alternator was putting out at 14 volts. I will certainly check the belt. Any other suggestions? What about an inercooler cap that has lost it's rated tention and is too loose? Thermostat? I will also check for corrosion at the "clamshell" intake water hose connection; but would have thought that the overheating would have shown up sooner in the trip if that were the case.

09-08-2006, 07:28 AM
"A loose expasion tank cap may 'drain' the cooling liquid, but generally only to a certain level. A leaking circulation pump may drain it all. A stuck open thermostat may make that engine overheat, and water to 'boil' out.
Suggest You refill the system and start the engine. For testing and short time running You do not need to add 50/50 antifreeze, but do not let plain water stay in the system due to corrosion risk."

El Pescador
09-08-2006, 10:55 AM

I don't recall the tank caps in the Volvo Penta 4 cylinder fresh-water cooled engines having as much pressure as with the fresh-water cooled V-8s. However, is it possible that you have it closed only half-way intead of full?

One reason why you could have antifreeze coming out of the tank is because of a blown head gasket. If combustion gases find their way into the cooling water, the easiest way to relieve pressure is through the "radiator cap". However, you wound only experience a suden increase in cooling water temperature if your system did not have enough coolant left.

Other reasons for a sudden water temperature increase would be silt or mud clogging the raw water strainer, or a piece of plastic obstructing the water intake grids in the outdrive."

09-08-2006, 11:12 AM
"I had an over heating problem with my same exact engie as well and was helped on here. But found out that my sea pump was not working right, and that the clamp that holds the rubber exhaust coupler on the back of the motor on the left hand side was loose and I was losing all my collant as well into my bilge. I left the cover open and ran the motoro to check for leaks and water was pooring out of there. Just run your motor in the drive way and leave the cover open and watch to see where water is leaking from. Make sure you have your ears on the outdrive and it is getting plenty of water. You could also see if water is even getting to your exhaust to cool it down by unscrewing the draining screws that are on the copper pipe coming from the back of your heat exchange on the left side. There are two of them ONe on the pipe, and the other is on the exhaust. Good luck."

KN Kai
09-10-2006, 02:10 PM
What is the normal(suggested) rated tension of the coolant cap? Thanks.

09-10-2006, 08:50 PM
"There is no 'tension' specs on that kind of caps, they have a pressure spec on top which spesifies the max pressure before it releases. Check that the gasket is good and seats properly, otherwise change the cap."

KN Kai
09-10-2006, 10:41 PM
Let me be more specific. 7 lb? 16 lb?