AQD40A Overheat

[MintImp]

Can anyone help.

One of my engines overheats by losing water out of the header tank. There is no oil mixing so I hope its not the head gasket.
Does anyone know how to bleed the fresh water system as the manual says look on the manifold, being an old engine I can not read the instructions.

Any suggestions would be greatly recieved.

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[oldgit]

Hi,Mr mint.Assume that you have checked raw water filters and impellors as a starter.Is the boat on legs or shaft.How about heat exchanger/oil cooler has that been cleaned in recent years.Wonder if coolent being forced out by temperature rise.If oil was getting into cylinders surely exhaust would appear as blue smoke.
My volvo workshop manual does not mention any special stuff regarding bleeding coolent.Have a couple of stickers on my 40A which show the expansion bottle pipe connections but precious little else.

<hr width=100% size=1>Nastro Azzurro.Hoegaarden.Chang.Tiger.

 

[MintImp]

Thanks for your reply

Its on legs, the raw water is pumping fine I'm counting on an air lock as water is exiting the expansion tank with the temp at around 75. The engine also runs the hot water system.
After emptying into the bilge the water from the expansion tank is not backfeeding to replenish the system, so there is allways water in it.

Any other thoughts would be appreciated

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[oldgit]

Just a thought have you had the boat very long ie. has it just started doing it.Mine was losing water via expansion tanks cos I kept filling them up to much.When water level is no more than half/ three quarters up the bottle,the stuff stays in.
Not sure where you are but if all else fails the bloke at Medway Bridge may be the only answer if not then man at <A target="_blank" HREF=http://www.coastalrides.co.uk>Coastal Rides</A> might prove bit cheaper due to his supply of second hand bits.

<hr width=100% size=1>Nastro Azzurro.Hoegaarden.Chang.Tiger.

 

[eddieperkins]

You need to fill via the filler cap on the thermostat housing, not via the expansion bottle. When the bottle shows up to the marks run the engine for a while with the filler cap off (can take up some time) and ensure the fluid in the expansion bottle is up to the minimum mark. Initial overhest may have been due to plastic bag around leg. If it is the headgasket you should be able to detect exaust fumes comeing out of the filler cap and bubbles so I am told.
Good luck,
Eddie

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