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View Full Version : Volvo Engine Air Valves?



Boat_Mon
10-13-2003, 10:40 AM
Guys,

I have a 5.0 302 with a Penta outdrive. I noticed two air valves (like the kind on bike tires). One is right above the thermostat housing and the other is in the rear of the engine and I don't know what its over..oil cooler maybe? Anyone know what there for?

Greg K
10-13-2003, 12:48 PM
Not sure if they are stock, but I'm guessing they're used for winterizing to blow out water from the engine block and lines using compressed air.

Boat_Mon
10-13-2003, 01:11 PM
They definitely look stock, think theres any limit to psi or just charge by 3hp compressor up and go? Doesn't seem like there would be much risk. I'll look into it a little more. Thanks.

MOP
10-13-2003, 07:03 PM
If it is fresh water cooled they are more than likely air bleeds to let trapped air out of the system.

Boat_Mon
10-13-2003, 08:04 PM
can they be used to blow the water out of the block (in addition to draining at all the regular hoses and plugs)?

MOP
10-13-2003, 10:13 PM
Don't make much sense to blow a block out and leave it dry, you want to keep cast iron wet. You should drain it and fill it back up with 50/50 mix for the winter.

Boat_Mon
10-13-2003, 10:49 PM
M.O.P.

Great info. I've read quite a bit on how several guys on the board do their winterization, the only problem I have is the mfg. says to strictly follow their instructions to drain the entire block to prevent freeze and things will be fine. I've always used the antifreeze 50/50 mix on the Donzi and previous boats, just thought I'd try to go by the "book" this time round.

Thanks for your advice, I think its the safe way to go.