Water/coolant overflowing at radiator cap

2007 DODGE CARAVAN
170,000 MILES • 3.8L • V6 • 2WD • AUTOMATIC
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JOHN2007DODGECARAVAN
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  • 1 POST
I was driving my van with a total of six passengers and was driving for twenty miles and I noticed the coolant overflowing from radiator cap for about one-half liter to the ground. The radiator cap looks like stocked up. Any suggestions about what I should do first to fix this issue. I’ll do it myself. Thank you.
Mar 23, 2022 at 3:26 AM
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SQM
  • ✓Experienced Mechanic
  • 6,383 POSTS
Hello,

If the coolant spills out of the cap and you do not have the engine overheating, then the issue is likely bad cap.
The spring on the cap can become weak or get seized causing the coolant to leak out.

This radiator cap is rated to hold 14 PSI of pressure, a weak spring will not be able to achieve that amount and leak.

The cap can also be tested using a pressure tester.

https://youtu.be/RLuoCuBbaRw

I have attached diagrams below for your reference.

Please let me know if you have any questions.
Thank you.
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Mar 23, 2022 at 8:14 AM
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