Evening,
I recently rebuilt my Mk2 Polo, and installed a top-fill radiator. The new rad has a cap on it, whereas the old one used an expansion bottle mounted to the bulkhead.
The old expansion bottle had an outlet at the bottom which went to the thermostat housing, and a small inlet at the top that was connected to a small outlet at the top of the rad.
The new rad has no provisions for this, so I blanked off the now unused inlet on the thermostat housing. The expansion tank is no longer present.
The issue is that the fill-point (rad cap) is now lower than the bleed point on the heater matrix. The old fill-point (expansion bottle cap) was higher than this.
The only way I have been successful in eliminating air in the system is to use a 2l bottle full of coolant, swiftly inverted and shoved in the rad. Squeezing the bottle forces the coolant into the system. With the heater matrix bleeder (highest point) open, the coolant eventually squirts out and I then close the bleed screw.
The thing I can't get my head around is that there is surely no room for expansion, as the rad is not the highest point and will therefore be completely full before the coolant comes out of the bleed screw. This also makes it impossible to check the coolant level, doesn't it?
Early models of the Mk2 polo use this same radiator, so it obviously can be made to work. I'm sure if there's even a problem, but it just seems like an odd concept to have the radiator cap lower than the highest point in the system.
Any input is greatly appreciated.
Thanks
I recently rebuilt my Mk2 Polo, and installed a top-fill radiator. The new rad has a cap on it, whereas the old one used an expansion bottle mounted to the bulkhead.
The old expansion bottle had an outlet at the bottom which went to the thermostat housing, and a small inlet at the top that was connected to a small outlet at the top of the rad.
The new rad has no provisions for this, so I blanked off the now unused inlet on the thermostat housing. The expansion tank is no longer present.
The issue is that the fill-point (rad cap) is now lower than the bleed point on the heater matrix. The old fill-point (expansion bottle cap) was higher than this.
The only way I have been successful in eliminating air in the system is to use a 2l bottle full of coolant, swiftly inverted and shoved in the rad. Squeezing the bottle forces the coolant into the system. With the heater matrix bleeder (highest point) open, the coolant eventually squirts out and I then close the bleed screw.
The thing I can't get my head around is that there is surely no room for expansion, as the rad is not the highest point and will therefore be completely full before the coolant comes out of the bleed screw. This also makes it impossible to check the coolant level, doesn't it?
Early models of the Mk2 polo use this same radiator, so it obviously can be made to work. I'm sure if there's even a problem, but it just seems like an odd concept to have the radiator cap lower than the highest point in the system.
Any input is greatly appreciated.
Thanks
