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Re: MGA - Coolant overflow and recovery

To: rmason@ro.com
Subject: Re: MGA - Coolant overflow and recovery
From: "Eric R. Stephen" <bk996@freenet.carleton.ca>
Date: Sun, 19 Jul 1998 09:49:59 -0400
Rich: Thanks for the response.  I checked the radiator cap and there is
a gasket on the "throat" end of the cap (below the overflow tube), but
nothing but raw metal on the underside of the cap.  Looks like I will
have to pull out some rubber scrap and fabricate one.  The overflow unit
has a hose running from the overflow tube to the screw-on top of the
recovery bottle.  There is a hose running (inside) from the screw on top
to the bottom of the bottle.  Even without a complete vacuum seal (at
the top) I would imagine any vacuum applied would be via the hose which
is emersed in coolant.  Sometimes the obvious is overlooked!

Eric

Rich Mason wrote:
> 
> At 03:17 PM 7/13/98 -0400, you wrote:
> >I scavaged a coolant overflow unit off a Mazda in our local recycled car
> >lots (junk yard).  I hooked this up to the overflow pipe on the radiator
> >neck hoping to avoid the constant loss of antifreeze I have been
> >experiencing from the moment I purchased the MGA last spring.  The
> >radiator currently has a 7PSI cap.  The coolant recovery system is
> >recovering fluid overflow but the system is not sucking the fluid back
> >into the radiator when the engine cools.  I have to physically remove
> >the antifreeze from the overflow unit with a turkey baster (dedicated)
> >and add it back into the radiator. The overflow tube was flared and
> >soldered on the neck end and is air tight (vacuum check). What am I
> >doing wrong??
> >
> >Eric
> >
> >
> Eric-
> 
> I didn't want to post this response - but figured the obvious is sometimes
> overlooked.  Is the vent tube routed down into the bottom of the bottle?
> 
> If so - my second guess is that the pressure cap isn't sealing well on the
> top edge of the radiator opening.  There are two seals on the rediator cap -
> one that seals in the "throat", below the overflow vent, and one on the
> undeside of the cap - which seals on the very top of the radiator opening.
> When the fluid/gas pressure in the radiator exceeds the rated relief
> pressure, the spring-loaded plunger lifts up and allows water and steam to
> exit the vent line, and then re-seats.  On cooldown, the lower pressure in
> the radiator tries to suck some air or water back in.  If the cap isn't
> sealing well, the air comes in from there rather than lifting the column of
> water from the overflow bottle.
> 
> Good luck.
> 
> Rich Mason
> '73 MGB
> Madison, AL
> ------------------------------------------
> e-mail--> rmason@ro.com
> MG Page-> http://ro.com/~rmason/mgpage.htm
> NABMS --> http://www.geocities.con/MotorCity/Garage/5207/
> ------------------------------------------

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