Parts for your 2016 Ford Transit-Radiator cap

2016 Ford Transit radiator cap — what’s actually fitted?

Short answer: a traditional radiator cap on the radiator isn’t used on the 2016 Ford Transit. Ford engineered this model with a sealed, pressurised cooling system that fills and vents through a separate expansion tank (often called a degas bottle) under the bonnet. The pressure cap sits on that tank, not on the radiator itself. This setup is documented in the Ford Workshop Manual for Transit (2015–2019), Section 303-03 Cooling System, which diagrams a pressurised degas bottle and notes no service cap on the radiator. The 2016 Owner’s Manual also directs owners to only remove the coolant reservoir cap when the engine is cool, reinforcing that the service point is the tank, not the radiator. Motorcraft’s parts catalogue likewise lists a “Cooling System Pressure Cap” for the degas bottle rather than a radiator cap.

Why ditch the old-school radiator cap? Modern cooling systems prioritise reliable air purging, higher packaging efficiency, and stable operating pressures. Relocating the cap to a high-mounted expansion tank lets the system continuously bleed air into the bottle, reduces hot spots, and keeps the radiator buried behind the grille fully sealed. That means fewer leaks, more consistent temps across the loop, and better access for topping up coolant where it’s safest.

• Air separation and fill point: The degas bottle is the highest point, so air naturally collects there and is purged, making fills and bleeding easier.
• Consistent pressure: A calibrated pressure cap on the bottle maintains system pressure, raising the boiling point and helping prevent localised boiling.
• Safety and serviceability: Opening the tank (when cold) is safer than leaning into the grille area, and there’s a clear MIN/MAX level to go by.

For owners and techs, the practical takeaways are simple. If the Transit is losing coolant, puking into the overflow, or showing odd pressure behaviour after cool-down, don’t go hunting for a radiator cap—it doesn’t have one. Inspect the degas bottle cap: its rubber seals should be supple, clean, and free of nicks, the spring should move smoothly, and the cap’s pressure rating (typically around 140 kPa/20 psi, verify what’s printed on your cap) should match the vehicle spec. Replace a tired cap—it’s an inexpensive fix that protects the water pump, radiator, and heater core. Always top up with the correct Ford-approved coolant mix via the expansion tank only, and only when the engine is cold.

FAQs

Where is the “radiator cap” on a 2016 Ford Transit?
There isn’t one on the radiator. The pressure cap is on the coolant expansion tank (degas bottle) under the bonnet. Only open it when the engine is completely cool to avoid scalding.

What pressure cap does the 2016 Ford Transit use?
Most models use a cap rated around 140 kPa (about 20 psi), but always check the rating printed on your existing cap or confirm by VIN with a Motorcraft-spec replacement to match your engine and market.

How can someone tell if the degas cap is failing?
Common signs include coolant smell, staining around the cap, hoses that collapse after cool-down, unexplained coolant loss, or overheating under load. If in doubt, replace the cap—it’s a low-cost, high-impact maintenance item.