ADDING A STOCK VW OIL COOLER
It's no secret that Volkswagens run at higher engine temperatures than we're used to over here in the States. Add the additional heat load of a turbocharger and the oil temperatures can get really high. Before adding the turbo, my GTI oil temperature usually ran around 100 degrees C during hot summer days with the A/C turned on. After adding the turbo, the temperature went to 120 degrees or more. This caused me some alarm as I was concerned that these temperatures would cause the engine oil to break down, and started me on the path to researching the various oil cooler kits that are out on the market.
I first looked at the kits available at Euro Sports Accessories and was quite impressed with the quality of the kits, but by the time you added everything up, a light-duty kit was over $200, and since my car has A/C, fitment would be a big issue (If you do not have air conditioning, then I highly recommend the addition of one of these coolers, as you can place as large a radiator as you desire in front of the radiator and secure it with something as simple as zip ties). In addition, all the additional plumbing for the turbo oil lines, etc. has made my engine compartment pretty tight on space.
I happened to have a spare OEM Volkswagen oil cooler sitting around the garage, and I started to wonder if I could make this work on my engine. The answer is a resounding yes! Oil coolers of this nature were fitted to many Sciroccos, Convertibles, and Jetta GLIs during the 1984 model year. They were also used on A2 Golf GTIs (8v and 16v), Scirocco 16v, and Cabriolets, and due to the commonality of parts between model years and platforms, what fits one of these cars fits the Rabbit GTI as well.
To add the cooler, you will need the following parts:
Oil cooler, part number 068117021B.
This goes between the oil filter base and the oil filter.
Oil filter threaded pipe (or "union"). This is a longer version of the fitting that the oil filter screws to. I had one on hand, so I am unsure of the part number. It is an item available at the dealership.
Oil cooler securing nut. Once again, I had one on hand, so I am unsure of the part numer.
Oil cooler o-ring, part number 038117070A. Seals between the cooler and the oil filter base
Hose, part number 027121096A. This hose routes
from the cylinder head upper radiator hose flange to the oil cooler
inlet
Hose, part number 068121058C. This hose replaces
the existing hard-pipe to water pump connection with a "T" fitting.
The
branch attaches to the oil cooler.
Below is a picture of the cylinder head flange that you will need. Unfortunately, although I was able to find a valid part number for this item some time ago, but have since lost it. Even with the part number, the item is not a regularly stocked item, and is quite expensive at the dealership. I found mine at a local salvage yard, where I quite literally stepped on it as it was lying on the ground halfway buried in the dirt!
You will note that there are three openings on this flange rather than the two that you are used to. The primary one out the front for the upper radiator hose, one to the water pump out the left side (bypass hose) and one at the bottom, which goes to the oil cooler.
Installation is straightforward:
After completion my oil temperatures stay comfortably in the 110 degree C range, even during 100+ F outside temps and a/c going full blast.
Many people are uneasy about using this setup, mainly due to the concern of having water and oil so near each other in an item that looks like it could fail rather easily. I've not experienced any issues with the VW oil cooler in any of my past vehicles (as a matter of fact the cooler I have came from the engine out of my 1987 GTI 16v, so it has well over 150k miles on it), so I'm comfortable with what I've done. Greg Raven in the Watercooled Volkswagen Performance Handbook is critical of the factory cooler because he doesn't think the stock radiator is capable of rejecting the additional heat, but I'm proof positive that he is wrong on that point!
