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How to Choose the Correct Radiator Cap

Did you know?
Cooling systems have an effect on everything from power to gas mileage and everything in between.
When was the last time that you changed an oil filter? Added coolant or brake fluid? How about replaced your radiator cap?
Radiator caps are the most overlooked component of your cooling system and ironically the least expensive. Replacing your radiator cap regularly can save your customer money at the pump and save wear and tear on your cooling system overall. Caps have a seal that can wear away over time. And over time your fuel costs will also increase.
*Measurements are reference only and may vary slightly with application.
*Matching EXISTING PSI is critical in selecting your radiator cap.
FILLER NECK WIDTH (outer dimension) | FILLER NECK DEPTH | PSI (lbs) | FOR COOLANT RESERVOIR SYSTEMS | OVERALL HEIGHT | OVERALL DIAMETER | NOTES | PART # |
32mm (inner dimension) | 10mm | 13 | YES | 0.68" | 1.71" | Upper seal | RW0021-65 |
32mm (inner dimension) | 10mm | 16 | YES | 0.68" | 1.71" | Upper seal | RW0021-66 |
32mm (inner dimension) | 16 mm | 13 | YES | .96” | 1.77” | Upper seal | RW0021-6 |
32mm (inner dimension) | 16 mm | 16 | YES | .96” | 1.77” | Upper seal | RW0021-23 |
32mm (inner dimension) | 16 mm | 26 | YES | 0.96" | 1.77" | Upper seal | Z19210 |
2.2" | .75” | 4 | NO | 1” | 2.3” | NO upper seal | RW0021-11 |
2.2" | .75” | 7 | NO | 1” | 2.3" | NO upper seal | RW0021-81 |
2.2" | .75” | 7 | YES | 1.20" | 2.3" | Upper seal | Z17705 |
2.2" | .75” | 7 | YES | 1” | 2.3” | Upper seal | RW0021-1 |
2.2" | .75” | 10 | NO | 0.96" | 2.3" | NO upper seal | RW0021-73 |
2.2" | .75” | 10 | YES | 0.96" | 2.3" | Upper seal | RW0021-70 |
2.2" | .75” | 10 | YES | 0.96" | 2.3" | Upper seal | RW0021-72 |
2.2" | .75” | 10 | YES | 1” | 2.3” | Upper seal | RW0021-5 |
2.2" | .75” | 10 | YES | 2.3” | 3.5” | Massey Freguson Special | RW0021-24 |
2.2" | .75” | 13 | YES | 1.20" | 2.3" | Upper seal | Z17704 |
2.2" | .75” | 13 | YES | 1.4” | 2.3” | Lever Lift with upper seal | RW0021-3 |
2.2" | .75” | 13 | YES | 1” | 2.3" | Upper seal | RW0021-80 |
2.2" | .75” | 13 | YES | 1” | 2.3” | Upper seal | RW0021-2 |
2.2" | .75” | 16 | YES | 1.20" | 2.3" | Upper seal | Z17700 |
2.2" | .75” | 16 | YES | 1” | 2.3” | Vented Drop Valve with upper seal | RW0021-12 |
2.2" | .75” | 16 | YES | 1” | 2.3” | Upper seal | RW0021-22 |
2.2" | .75” | 20 | YES | 0.96" | 2.3" | Upper seal | RW0021-74 |
2.2" | .75” | 20 | YES | 1.14" | 2.3" | Upper seal | Z19200 |
2.2" | .75” | 24 | YES | 1.14" | 2.3" | Upper seal | Z19201 |
2.2" | .75” | 28 | YES | 1.14" | 2.3" | Upper seal | Z19202 |
2.2" | 1" | 4 | NO | 1.2” | 2.3” | NO upper seal | RW0021-15 |
2.2" | 1" | 7 | NO | 1.2” | 2.3” | NO upper seal | RW0021-14 |
2.2" | 1" | 10 | NO | 1.4” | 2.3” | NO upper seal | RW0021-25 |
2.7” | .75” | 4 | NO | .96” | 2.8” | NO upper seal | RW0021-9 |
2.7” | .75” | 7 | NO | .96” | 2.8” | NO upper seal | RW0021-4 |
2.7” | .75” | 7 | YES | .96” | 2.8” | Upper seal | RW0021-292B |
2.7” | .75” | 10 | NO | .96” | 2.8” | NO upper seal | RW0021-40 |
2.7” | .75” | 15 | NO | 1" | 2.8" | NO upper seal | RW0021-77 |
2.7” | .75” | 15 | YES | .96” | 2.8” | Upper seal | RW0021-294B |
2.7” | .75” | 15 | YES | 1.12" | 2.8" | Upper seal | Z17703 |
Click product link for more information | 10 | 1.08" | 3.11" | Plastic cap threaded | RW0021-79 | ||
Click product link for more information | 15 | 1.08" | 3.11" | Plastic cap threaded | RW0021-78 | ||
Click product link for more information | 15 | 1.48" | 2.54" | Plastic cap threaded | RW0021-75 | ||
Click product link for more information | N/A | 1 | 2.36" | Surge tank cap | RW0021-76 |
Want more information?
Contact your local Northern Radiator Sales Rep