Northwest Nova

Overview

There were quite a few different gas or "fuel filler" caps used on the Nova in the 1962 - 79 period. Just about all of them are still available in some form (reproduction, aftermarket replacement, AC Delco). The ones that cause the most headaches are the 1962 – 67 caps, followed by confusion over "vented" vs. "not vented" in later years. Here we will attempt to give a brief overview to help you sort them out.

→ 1962 – 67
The original parts books show the 1962 – 67 gas caps as "Nova only", of which there were two different versions. We look at the design differences between the two versions here. The gas caps were painted the car's body color out of the factory. Early replacements came in primer and had to be painted to match the car. GM quickly went to a chrome service replacement, probably to spare mechanics and customers the hassle of having to paint the new cap. The parts books seem to indicate the primer replacement cap was only available for the 1962 – 64 Chevy IIs, we did not come across a listing for 1965 – 67 models.

Originals were a crappy design and known to break. Also easy to steal. Big reason why you rarely see originals in any shape. There were two optional gas caps available from the dealer — a chrome locking gas cap with a raised bowtie center and the "S" handle gas cap, which had an easier to grasp black plastic handle. There is no RPO code for either of these optional gas caps, you do see them advertised in dealer sales literature.

Reproductions are also not of the best quality and can break as well. The chrome ones tend to spot rust quickly if consistently exposed to the elements and not kept properly polished (waxed). You can still find long discontinued period auto parts store replacements at swap meets and eBay. Some fit well, some do not. Visually they can vary wildly and usually do not match the original GM caps.

→ 1968 – 74
1968 and later caps fit other GM cars and are still plentiful. They do not have the quality issues the earlier caps did. Replacement or non–reproduction (i.e. visually not "correct") caps can normally be purchased at auto parts stores. NOS GM ones are usually prevalent on eBay. Purchase an auto parts store unit unless you are building a correct restoration.

In this period the main thing you need to be aware of is vented vs. non–vented gas caps. This is determined by if your car has (had) Evaporative Emission Controls or not. EEC or E.E.C. is a non-vented fuel tank with vapor recovery lines running to a charcoal can (normally in the engine compartment) and then purged to the air cleaner housing or carburetor. The system debuted in 1970 California sold passenger vehicles and was 50 state applicable in 1971. It is important to use correct replacement parts with EEC equipped vehicles to prevent both drivability issues and fuel tank damage. The system does not rob power from the motor and should be kept in place unless heavily modifying the vehicle.

→ 1975 – 79
As with the 3rd gen gas caps, these are a common design that were used on other GM vehicles. They can be found at local auto parts stores and one is still available from AC Delco. All are not vented as all cars had an EEC system of some type by this point.