Article by Ted Hedman
Here’s a cool radiator conversion for those hot summer days when all you can do is watch your TEMP gauge rise ever closer to the red zone. You may have heard that the aluminum VW Rabbit crossflow radiator makes a good swap for a 510, but always wondered how. Well, read on because we’ll show you how easy it is to fit this lightweight, efficient radiator into your 510.
The first step is to acquire the radiator. I was lucky enough to find the radiator you see pictured here at the local Pick Your Part wrecking yard. It was in a ‘77 Rabbit and was obviously an aftermarket replacement. It was made by Valeo, which I later found out is a quality aftermarket parts supplier for water-cooled VW’s. The Valeo part number is 883435 and is for a ‘76-’77 Rabbit or Scirocco 1.6 f.i. without A/C. You can order a new replacement radiator from VW (the part number is 171-121-253-G) but they are very pricey. The V-leo unit should run you about $100 new.
Photo 1 shows the engine side of the radiator. Note from Photo 1 that the Rabbit radiator has a thermostatic
switch mounted in the side tank at position (D). This can be wired to control an electric fan. You can also
see from Photo 1 that the coolant inlet (A) and outlet (B) are both located on what would be the right side
(passenger side) of the car. The standard 510 radiator has the inlet offset to the left (driver’s side) of the
car. This is not a problem! Thanks to Don Karry for his tip in the February ‘94 issue of 510 Again, there’s
an upper radiator hose available that fits perfectly when trimmed on one end. That hose is a Gates part
number 21574 or equivalent. Recently, I’ve also heard that the NAPA hose #NBH7558 and the Pep Boys
hose #71189 will also work.
Since my local parts house carried only Goodyear hoses, I used the Goodyear equivalent, part number
61439. It is a 1.25” ID hose and fits the VW radiator inlet, but is a little small for the L-series thermostat
housing outlet which normally requires 1.5” ID hose. I was able to fit the smaller hose over the thermostat
outlet without a problem. A 15” flex hose works well for the lower radiator hose. The 1.25” ID flex hose
I found seemed like it would be very hard to stretch over the slightly larger water pump inlet on the engine,
so I chose the 1.5” ID hose and clamped it a little tighter to seal at the 1.25” radiator outlet. Photo 2 shows
the two hoses used for this conversion. The upper hose has already been trimmed to fit.
Photo 3 shows the front side of the radiator, ready for installation. In a Rabbit, this radiator is only
attached to the car at three points via pre-formed horizontal tabs built into the plastic side tanks. These
points are denoted as (A), (B) and (C) in Photo 3. As you can see from the photo, I’ve added “L” brackets
at (A), (B) and (C) which are used to attach the radiator to the radiator core support. The brackets are
attached to the radiator using existing holes in the radiator mounting tabs.
All the brackets I used for this conversion came from an Automotive Universal Mounting Bracket kit sold by Radio Shack (catalog # 270-023A). Bracket (A) is used as is, with the bolt to attach the bracket to the core support passing through the third horizontal slot from the top (as shown in Photo 3). Bracket (B) was identical to (A) until I cut off the vertical slot so it wouldn’t interfere with the lower frame section of the chassis that runs across the front of the car below the radiator. Bracket (C) is cut to length and formed into an “L” from a piece of universal strapping that also came with the bracket kit.
