PSA: Check Your Coolant Caps!

ebbnflow · **Posted:** Tue Nov 17, 2015 8:09 pm

Lately I've felt like my coolant bottle has too much pressure. There is no fluid in the overflow side. I bought a coolant pressure kit for another project and figured I would test the cap on my CRD.

The cap looks to be an original Mopar 16 psi cap. Well, my pressure test confirmed my suspicions. The cap held pressure over the limit of my pressure tester (25+ psi). It eventually leaked pressure out the seal, not the relief.

I picked up new one today. I tested it and it opens right at 16 psi.

End of Public Service Announcement!

olypopper · **Posted:** Tue Nov 17, 2015 8:26 pm

If you've gotta have one fail, that's the way you want it. The blue oval boys have the exact opposite problem. The Ford caps leak bleed off pressure too soon and the water actually boils in the water jackets!

ebbnflow · **Posted:** Thu Nov 19, 2015 2:18 am

I'm certainly glad that it didn't fail that way.

Running the cooling system at 25-30psi can't be good for the motor either.

flash7210 · **Posted:** Thu Nov 19, 2015 6:55 am

Too much pressure will cause the hoses to leak or burst.
Can also cause the oil cooler to break and leak internally.

Personally, I think the 16psi cap is too much and have switched to a 7 psi cap.
Ran all summer like this and never lost a drop of coolant.

PSA: Check Your Coolant Caps!

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