I am so grateful, it ended up being a radiator cap!!!!! Super cheap fix!!!! Still 180, but goodness, I am so thankful.
Pros: super cheap fix
Vehicle:
Toyota Camry
Owner reviews for radiator cap
Manufacturers
Could also be something as simple as a radiator cap.
Pros: simple fix
Vehicle:
Honda
I've always run a motorrad with the relief valve in mine. Works great
Pros: works great
I bought a mopar on rock auto last year and it’s doing great.
Pros: doing great
Definitely try a new Radiator cap. Mishimoto can be hit or miss for quality and also possibly not rated to match the pressures of the OEM cap.
Cons: hit or miss quality
If you want to start off cheap, replace you're radiator cap. I had it happen once where the seal went bad and then it started leaking.
Pros: cheap replacement
Cons: seal went bad, leaking
I bought a duralast radiator cap from autozone and replaced it, but was still a little low on coolant. It looks to me like the rubber flap on the bottom of the cap was covering the port that allows pressure to relieve itself into the reservoir, meaning the pressure stayed in the system instead, breaking the plastic of the radiator.
Cons: pressure stayed in system
Vehicle:
Lexus
Mileage: 215000 km
Every. Damned. Radiator. Cap. I can find for sale is a motorad. I've gotten two now that came in different brand boxes, neither will hold much pressure or draw in coolant when the engine cools off. I'm seriously doubting how much longer I can deal with every new part being fucking garbage.
Cons: poor sealing, no pressure, cracked rubber
Make sure you get an OEM Toyota rad cap. Bought two from rock auto and both failed the autozone cap tester.
Cons: failed cap tester
Vehicle:
Toyota
The cap which came on the Koyorad is probably a two way cap. If so it needs to be replaced with a Subaru one way cap.
Cons: wrong cap type, needs replacement
Vehicle:
Subaru
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Owner reviews for radiator cap
As of March 2026, PartReview has 16 reviews across 11 manufacturers for radiator cap. 11 of them have enough reviews to participate in the ranking of this part.
Popular manufacturers of radiator cap
The most popular manufacturers of radiator cap on PartReview include:
- MotoRad - 3 reviews. PR Score: not available yet, average rating: 3.1.
- MISHIMOTO - 2 reviews. PR Score: not available yet, average rating: 2.0.
- OEM Toyota - 2 reviews. PR Score: not available yet, average rating: 3.0.
- OEM Honda - 2 reviews. PR Score: not available yet, average rating: 5.0.
- Duralast - 1 review. PR Score: not available yet, average rating: 1.0.
Most opinions about performance and characteristics of radiator cap are collected on these pages.
Top manufacturers of radiator cap
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Comparisons of radiator cap manufacturers
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