Genuine Motorcraft RS-7 Radiator Cap (NOS)
Restore the factory-correct cooling system pressure and period-accurate aesthetics of your classic powertrain with this genuine Motorcraft RS-7 Radiator Cap. This authentic New Old Stock (NOS) component, also identified by Ford engineering number A1TZ-8100-A, is a specialized 4 PSI low-pressure cap designed for open cooling systems common in the late 1940s and early 1950s. Engineered for heavy-duty and passenger applications, this "Cam-On" style cap is essential for 1948-1952 Ford F-Series trucks (F-1 through F-5), 1949-1951 Ford and Mercury passenger cars, and even vintage Jaguar XK140 models. Manufactured in the USA to original factory specifications, this stainless steel finished cap ensures proper pressure regulation for your Flathead V8 or L-Head 6-cylinder engine, making it a critical piece for any factory-correct restoration.
Key Features:
- Brand: Motorcraft
- Part Number: RS-7
- OEM Number: A1TZ-8100-A
- Interchange: Stant 10281, Gates 31307, AC Delco RC-5, Autolite RS-7, T-101
- Position: Radiator Filler Neck
- Engine Fitment: Flathead V8 / I6 L-Head / 3.4L L6
- Origin: Made in USA
- Condition: New Old Stock (NOS)
Verified Vehicle Fitment:
| Make |
Model |
Year |
Engine |
Notes |
| Ford |
F-Series Trucks (F-1 / F-2 / F-3 / F-4 / F-5) |
1948-1952 |
V8 / I6 |
Flathead / L-Head Models |
| Ford |
Passenger Cars (Custom / Deluxe / Crestline) |
1949-1951 |
V8 / I6 |
Non-pressurized Primary Radiator |
| Mercury |
Eight / Monterey |
1949-1951 |
Flathead V8 |
Early Production Systems |
| Jaguar |
XK140 |
1954-1957 |
3.4L L6 |
International Fitment Confirmed |
| Federal |
Trucks (All Models) |
1942-1958 |
All |
Heavy Duty Applications |
Fits Years:
1941 1942 1943 1944 1945 1946 1947 1948 1949 1950 1951 1952 1953 1954 1955 1956 1957 1958
Note on Stock Photos: Due to our inventory of multiple identical units for this specific part number, we utilize representative stock photos for this listing. You will receive a component that strictly meets all listed specifications and fitment requirements. Please be aware that because these are vintage parts, minor cosmetic variations—such as surface finish, color, or production markings—may exist between different manufacturing runs. These slight aesthetic differences are a result of historical production processes and do not impact the part's integrity, performance, or authenticity.
A Note on Fitment Accuracy: We manually research and cross-reference our fitment data using vintage manufacturer catalogs. While we strive for 100% accuracy, these decades-old resources—and the humans reading them—can occasionally contain errors. Additionally, these parts may fit other vehicles and years not explicitly listed in our data. To ensure a seamless restoration, we kindly ask that you perform your own due diligence and verify that this specific part number is correct for your application prior to purchase.
Unbeatable Prices & Expectations
While many of our vintage parts were manufactured decades ago, they remain unused and high-quality. Some original boxes may show signs of shelf-wear, such as dust, tape, or surface distress from years of storage. Rest assured, the components inside have been inspected to ensure they are complete and ready to help you finish your project without breaking the bank.
