Parts for your 2018 Ford Transit-Radiator cap

2018 Ford Transit radiator cap: what it is (and isn’t)

For the 2018 Ford Transit, there isn’t a traditional radiator cap mounted on the radiator neck. Instead, the van uses a sealed, pressurised cooling system with a remote expansion (degas) bottle that carries the pressure cap. Ford’s 2018 Transit Owner’s Manual describes checking and opening the coolant reservoir cap, not a radiator cap, and the Ford Workshop Manual (Transit 2015–2019, Section 303-03A Cooling System) details a pressurised degas bottle and a radiator without a serviceable filler neck. Ford parts catalogues for this model also list the cap with the reservoir, while the radiator assembly has no cap provision. Taken together, these technical references show a standalone “radiator cap” isn’t used on this vehicle.

Why did Ford go this way? Modern cooling layouts prefer a remote, pressurised reservoir to simplify filling and bleeding, reduce trapped air, and keep the bonnet line low by deleting a tall radiator neck. The pressurised cap on the degas bottle does the same job an old-school radiator cap used to do—holding pressure to raise the coolant’s boiling point and safely venting excess pressure—but it’s simply relocated to the most effective spot in the system.

For owners across Australia and New Zealand, that means any cap-related servicing or replacement happens at the coolant reservoir, not on the radiator itself. If there are overheating warnings, repeated low coolant levels, or a sweet coolant smell after driving, the reservoir cap and its rubber seal are worth a check. Only remove the cap when the engine is cold, and use coolant that meets Ford’s spec for the Transit. If replacing the cap, match the correct pressure rating noted on the original cap and in Ford service information. This keeps the system operating at the right pressure, helping the Transit stay cool under load—whether that’s urban deliveries or long-haul runs.

• No radiator-mounted cap on 2018 Transit, cap is on the pressurised coolant reservoir.
• Design improves air purging, packaging, and service access.
• Refer to the Owner’s Manual and Workshop Manual for correct cap handling and system specs.

FAQs

Does a 2018 Ford Transit have a radiator cap, and where is it?
It doesn’t have a cap on the radiator itself. The pressure cap is fitted to the coolant expansion (degas) bottle. That cap manages system pressure and venting, just like a traditional radiator cap would.

How often should the coolant reservoir cap be replaced?
There’s no fixed interval. It should be inspected at each service for seal cracks, distorted threads, or signs of venting. Replace it if there’s unexplained coolant loss, soft or collapsed hoses after cool-down, or if pressure testing shows the cap won’t hold the specified pressure.

What are the signs of a faulty cap on a 2018 Transit?
Look for recurring low coolant, overheating under load, coolant smell around the front end, stains around the reservoir, or hoses that collapse as the engine cools. Any of these can indicate the cap isn’t maintaining or releasing pressure correctly.