If you are using a mechanical fan, you may be able to attach the stock fan shroud to the radiator using the
attachment points on the back of the radiator that originally held the Rabbit’s electric fan assembly. There
are four raised bosses with screw holes that can be seen if you look closely at Photo 1.
You can also use these four mounting points to attach electric fans. I chose a pair of SPAL 7.5” electric
fans from Racer Wholesale (part number SPA-00358) because they were compact enough to fit to the back
of the radiator without interference with the water pump pulley by locating one on either side of the pulley.
I wired them through the thermostat switch to a lighted three position on-off-on switch located under the
dash. The indicator light comes on whenever the fans are on, and the three position switch allows me to
bypass the thermostatic fan control switch and run the fans continuously if necessary.
The hot tip is to replace the stock two-prong VW 197°F thermostat switch with a two-prong 180°F switch.
I bought the 180°F switch for $8 from Velocity Sport Tuning (a water-cooled VW tuner shop). After
reading the box, I found out that it is actually an aftermarket replacement for the 1.0L Chevy Chevette! It
is manufactured by a company called Wahler, and the Wahler part number is 6010.87. There’s another
part number that may be the original Chevette part number: 93212241. The switch is designed to turn on
at a water temperature of 189°F and turn off when the temperature falls below 180°F.
There’s a couple curious features about this radiator of which you should be aware of. First, there’s no
nipple on the filler neck for an overflow tube. I asked my friend, who happens to be a VW expert, and he
says the cap is designed to relieve pressure and overflow excess coolant around the threads of the cap when
things get too hot. Strange. To allow the use of a coolant recovery tank, I ordered a Moroso aluminum
filler neck tee from JEG’s (part number 710-63745, $20) that has a nipple for an overflow tube. It also
allows the use of a stock 510 radiator cap or equivalent. It easily splices into the upper radiator hose after
cutting a short section out of the middle. Note that if you splice the Moroso filler into the upper hose, you
don’t necessarily need the exact hose mentioned above, just two “L”-shaped hoses of the right length and
I.D.
The other curious feature is that the Rabbit radiator doesn’t have a drain plug! I guess VW just expected
you to loosen the lower hose and make a big mess! To get around that, buy a 4’ length of clear plastic hose
to siphon the coolant out. It’s really very easy and clean as long as you don’t get a mouthful!
Well, that’s about all there is to it! May you enjoy the ride in a cool-running 510 this summer!
|
SUPPLIERS
Jegs
Racer Wholesale
Velocity Sport Tuning
Virtual World Parts
|