OK, I'm stumped.
I bought a '69 SAAB Sonett V4 from a friend as a fun car. I had driven it
before but not done any work to it (naturally). Friend did the sort of
modification which I am known to do to these old suckers - put a pressure
tank in from a modern vehicle to improve cooling system pressure.
Now I'm not as familiar with the Sonetts as I am the 95 and 96 cars, which
in their 1969-and-later incarnations have crossflow radiators with a small
tube off one of the tanks for a 1-way overflow. These radiators have, from
stock, a filler neck on the opposite tank as well as a pressure/filler cap
on the overflow tank. Usually, I'll T in a Volvo 240 series or 900 turbo
tank to the inlet hose to the heater control valve which derives from the
intake manifold below the thermostat housing. Both the Volvo and the SAAB
tanks have an inlet at the bottom of the tank and an overflow which I have
always routed back into the small tube originally designed for the 1-way tank.
This Sonett had a lot of backwards plumbing which I attributed to the
situation I was suffering from when I received the car. I replaced the
thermostat with a 160 degree unit (failsafe), replumbed the system, et.c.
The Sonett radiators are crossflow but did not have either a filler neck or
a small port for the 1-way overflow found on the 96es. Alternatively they
had a larger tube to a header tank which doubled as the left-right strut
bar between the front spring towers. The tube off the radiator previously
used for this purpose has since been removed.
Instead of a SAAB or Volvo tank, my friend used a VW Rabbit tank from about
1981. This tank is very similar in operation, or so I thought, to the tanks
I use on 96es, with an inlet on the bottom and an overflow port. I plumbed
the lower inlet from the heater line as usual, but having no tank overflow
return possibility to the radiator, I T-ed it into the line returning to
the water pump. Previously it had been blocked off, a situation which I
think eventually contributed to the cap on the pressure tank having blown.
I have since replaced the cap.
I have a situation now where there is a significant amount of air trapped
in the cooling system, to the point where, after a short run, I get a good
amount of coolant pushed out when the cap is removed from the tank. The
temp gauge readings are very erratic, from 190 down to 120 or so in a
matter of seconds, so I know there's air going by the sender (below the
thermostat). Am I forcing air through this return tube from the tank into
the inlet on the pump? If so, where should the tank overflow return to as I
don't have the usual tube atop the radiator?
Please contact me privately - mailto:chip@wmsbrg.com
Cheers-
William "Chip" Lamb
West of Sweden SAAB
Charles City, VA.
http://www.wmsbrg.com/sweden/
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