VW Engine Frequently Asked Questions

Upright vs. Doghouse Fan Shrouds

Look at the back of your Fan Shroud, does it dis-connect from the oil cooler or does the shroud cover the oil cooler? JBUGS recommends you check what configuration your vehicle is currently running before you order as it may NOT be original after 30-40 years.

Upright Oil Cooler Fan Shroud

Air cooled VW's through 1970 originally featured the "upright-style" oil cooler that blew cool air from the back of fan shroud through the oil cooler fins next to the shroud.

Doghouse Oil Cooler Fan Shroud

Cars after 1971 originally had a redesigned "doghouse-style" fan shroud and oil cooler that were more effective than the upright oil cooler to help cool a bigger 1600cc engine.

VW Heater Boxes and Fresh Air Ducts

If you plan on running heater boxes be sure to select a fan shroud with fresh air/heater ducts and rear engine tin with fresh air/heater cut outs. If you live in a warm climate, have a custom engine, or do not plan to run heat/fresh air be sure to choose a closed fan shroud and rear engine tin.

WITH HEAT -This option includes the ducts on the front of the fan shrouds and rear engine tin, allowing you connect your fan to your heater boxes with fresh air hoses.

WITH OUT HEAT -This option features closed fan shrouds and rear engine tin. Perfect for hiding components beneath your engine bay and eliminating the need to plug your fan shroud.

Heat Riser Cut Outs

Heat Risers are tubes that start at the muffler or header and connect up to the manifold underneath the carburetor. They utilize the heat from exhaust air to keep the moisture absorbed in the air/fuel mixture from freezing. The heat also helps keep the air/fuel mixture vaporized as it moves through the manifold down its path to the heads.

Dual Carbs do not require heat risers as they lead directly to the heads, no long winding manifold. Also, some aftermarket exhaust do not run heat risers because they do not expel exhaust gas the same way original German mufflers did. Heat Risers should have an inlet and an outlet, but this cycle is interrupted by modern exhaust systems designs that do not create the vacuum necessary to circulate the air flow.

VW Heater Boxes and Fresh Air ducts.

Upright Oil Cooler Front Engine Tin
Original Single Port Engine design -for early VW engines. Hot air passed through the upright oil cooler inside the fan shroud and vented out over the piston cylinders. This design made one side of the engine run hotter than the other.

Doghouse Oil Cooler Front Engine Tin
Dual Port VW Engine design. Air passed through the external doghouse oil cooler - then vented out behind the engine under the transmission area. As a result of the improved design, engine tended to run cooler.

Single Port Engine & Dual Port Engine Cylinder Shrouds

Cylinder Cooling Shrouds directs cool air from fan shroud over hot cylinders and out under engine. Keeps heat from your heads out on your intake and engine bay. Please note if you need Single Port or Dual Port, depending on your engine configuration.

VW Alternator / Generator Stands and Straps

VW Alternator / Generator Stands support your alternator or generator as well as provide a location to fill your oil. Oil fillers are sold separately, and available in multiple styles to fit your car.

1 deflector plate and 2 stand gaskets will be needed for installation. Both gaskets to be installed, one on top of deflector plate, one below. You will notice 3 louvered "scoops" on the deflector plate. These scoops should dip down in to the opening, and the openings should open towards the passenger side of the engine block. This will help "deflect" engine oil back in to the engine case rather than help it exit.

Plain Firewall vs. Louvered Firewall

Give your Engine that custom look with a Solid or Louvered Firewall. The two different Firewalls are shown to the right.

Which Spark Plug Fits My Car?

Oil, Brake Fluid, Transmission Fluid Recommendations

Oil: Straight 30 weight (SAE30 or HD30) is recommended for colder climates, Straight 40 weight (SAE40 or HD40) is recommended for warmer climates.
20W50 can be used in a pinch but we recommend non-multigrage oil.
We do not recommend using synthetic oils in air-cooled VWs as they tend to lead to more oil leaks.

Brakes Fluid: We recommend DOT 3 Brake Fluid. DO NOT USE DOT 5.

Transmission Oils: Replace with 80w90 weight oil.

Synthetic oils are composed of thinner molecules, and in our experience tend to leak more frequently.