Degas bottle cap

[deamsphelps]

Wondering if I need another new cap. Just recently did egr block off. Yesterday I just drained coolant to do a filter system and the upper radiator hose. So I have it all back together and no leaks but when I shut down the engine after it is fully warmed up and go open the hood and listen, I can hear the cap hissing a little until pressure is gone. This cap is only a few months old and I got it online somewhere that I can't remember probably Amazon. It is rated at 16psi.

[deamsphelps]

In not so many words, should the system hold pressure when shut down or not? I'm not a mechanic, i just pretend to be one in my driveway.

[p8ntballn2]

it should hold pressure.. mine does.. i replaced my cap about 2 months ago with a Stant Cap.. when i shut the truck off.. it doesn't hiss like you're talking about. I'm not expert but it should hold i would think.

[dazed01]

The only way to know for sure is to pressure test the cap.

[deamsphelps]

I just bought a new one from Ford. It went on much tighter. But as I added some coolant later, it didn't seem to screw on as tight. I don't know how to pressure test a cap. Next time I will try a different brand. The one from Ford is the same one I just replaced. Made in India.

[tensixniner]

Ford has changed the cap at least twice. If in doubt, change it out ... a new one from the dealer should be like $12.
Not worth the effort to find someone with the tool, correct adapter and knowledge to use them to test you current cap.

Buying one online from ebay, amazon ... etc; you may be getting a new old stock cap.
Go to the dealer with your vin and the latest part number will be listed.

[p8ntballn2]

U need this

[deamsphelps]

Next time I will try the Stant. The only difference on the one I had (second one) and the one I replaced it with was one number. There were some numbers on the underside of the cap. there was an alpha numeric series that was the same but the bad one had a 1.3 and the new one was 1.4. So maybe it was some type of upgrade. It did seem to hold pressure but it seems like they wear out when you have to remove and replace them a few times. the clicks seem easier the more times you put it on.

[p8ntballn2]

I noticed that with my ford caps.. if you look at the underside of the Stant cap, the spring in there is much larger.. also, the stant cap doesn't click like the ford cap. you just tighten it on there snug and let it do its job.. i haven't had any issues with mine.

[bentstroke_02]

Where can i get a stant cap at? I have put my second cap on and it still leaks a little every now and then.