volvo engine leak again !!!!

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LeonF

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Having ascertained that it isn't the water pump leaking raw water into the bilge, I have discovered that it's coming from the overflow pipe attached to the freshwater coolant tank cap. At high revs water is pouring from this pipe. At first thinking I must have linked the systems inadvertently I realised that is not so as the exhaust is working fine, and the coolant tank water stays constant. Could sommething have corroded allowing the saltwater to enter the fresh water cooling system ?? It has been suggested that the O rings on the heat exchanger may have perished. Any other suggestions please?? Oh it's a 2010..
 
Do you have a header tank connected to the middle of this cap? If so then the cap is loose. The tabs that hold it down need to be bent slightly to make it seal and stop the water being pushed out through the overflow. RK Marine did it for me last year when I had the same problem.
 
Hi LeonF

Try getting a new rad cap!

If the spring is weak the pressure can blow water out via the overflow. I had this happen to one of our volvo 2030 last year. I never even thought of this until alant suggested it. It's worth a look see.

Good luck

Al
 
The cap seems a snug fit... surely this would mean the tank would need refilling ?? It doesn't, and the water in the bilges is salty....
 
Are the 2 hose clips (i hope this is the correct name) on the 2 rubber caps at the beginning and the end of the heat exchanger in place and thight enough?

If they don't seal enough you will pump salt water in your fresh water tank. You can observe this by starting without putting the cap on the freshwater tank. The coolant will rise fairly quick. (don't take of the cap when the engine is warm). On the other hand when your engine isn't turning you could also lose a fair amount coolant which can flow in the heat exchanger and from there to your outlet.

I had this problem with my volvo md22l
 
It is also possible that you have a leak in one of the copper tubes in the heat exchanger. But this is to my knowledge very rare.
You can take out the tube from the heat exchanger and check this.
Not so easy to monitor because the tube consists off twenty or so small tubes. Perhaps somebody knows an easy way how to check this.
 
the only way that salt water can get into the header tank is past the rubber caps or thru a busted tube. check the hose clips are tight on the rubber caps and are holding the tube and housing separate, to check the tube bundle take it out and clamp the rubber caps to it, block one end and clamp a hose pipe to the other, turn water on to hose pipe and see if it comes out of the bundle. my guess is that the rubber caps are not clamped correctly, when sorted flush the system thoroughly to get the salt out!! dont forget the calorifier!
stu
 
Are you sure it's not coming from the syphon breaker valve? The 2 overflow pipes come out close together in our boat. the valve dribbles water even though I have replaced it once and the Volvo agents swears it shouldn't leak. It fills up thengine bilge after a couple of hours motoring. Doesn't seem to be a permanent fix unless you can route the overflow pipe to a cockpit drain which we can't.
 
I am not sure what you mean by the syphon breaker valve...and it hasn't been a problem for the last three years. I reckon the other posters are probably on the right track and it is something to do with the hose clips etc into the heat exchanger. I remember my previous boat had a Beta engine and the brass heat exchanger had 'O' rings on either end....I suppose if these perish then they could let the two waters mix. I shall explore and let you guys know the outcome....and I take your point about rinsing the salt water through completely !!
 
Volvo syphon breaks are absolute crap, I've had new ones leak straight from the box, we used to junk them and fit Vetus ones, they cost a bit more but don't leak.
 
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