Volvo Penta AQ170 exhaust elbow valve

Daamo

Recruit
Joined
Nov 13, 2015
Messages
1
Hello,

I have had problems with my AQ170 not exhausting properly and I have traced back through the cooling system to find that the valve in the exhaust elbow has melted and broken into bits due to previous overheating issues (it is/was just a spring and a ball bearing in a plastic housing/cup) . However now it is removed, I do not know where to find a replacement or whether it is needed. Please if anyone has any information into what that valve is for ( i believe it to be a relief valve?) it would be very much appreciated but also, can i leave it without one as it is just coolant water exiting through the shield rather than the exhaust riser to the bellow, joining to the sterndrive. I do also have sufficient amounts of water exiting the sterndrive flapper housing with the exhaust fumes, therefore does it need a replacement? can i just leave this exit uncapped to exit through the transom shield, rather than only the bottom of the leg?

any info would be appreciated,

my apologies if this comes across vague or stupid.
 

captmello

Captain
Joined
Jun 30, 2008
Messages
3,826
It is described as a check valve and can be bought for 150 through iboats. I would guess it is there to prevent water from backing up into the manifold from the idle relief hose you describe coming from the transom shield. I can't say whether it's needed, however Volvo put it there for a reason.
 
Last edited:

HorizonblueDK

Petty Officer 1st Class
Joined
May 27, 2010
Messages
355
Strange thing with this valve. Some have it, some doesn't. The old exhaust knee that was on my AQ170 was very rusty and didn't have the valve, so when I made a new one in stainless steel, I didn't bother to add one. Water is mixed with exhaust gas in the knee, haven't had any cooling or water reversion issues.
 
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