coolant cap problem.

[Skye]

Easy to perform like once a year.

That's the plan. I'll be doing same once a year.

Oh I know, right? Fueling the passion. Almost any day I can spend some time here ends in a learning experience, reviewing cool photos, laughing at someone else's jokes or just enjoying taking part.

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[Cobra Jet]

Thanks for the insight. Checked mine this morning.

1. Push down, slowly unscrew and remove cap.

2. Take 1 Q-tip, douse with Silicone spray.

3. Apply Q-tip to both rubber O-rings and seating (flat) surfaces.

4. Re-attach cap.

5. Repeat steps 1-4 one more time. Be sure to listen for the "click" to ensure cap is on.

I was thinking about this coolant cap "issue" again. My original thought is the cap is made of inferior plastics that are prone to becoming brittle due to the under hood heat cycles.

I'm going to take a guess on this - but I am now thinking many of these broken coolant caps are happening because owners are not "pushing down" on the cap first, before trying to twist it off. They experienced the "it's not turning", try muscling it off and the cap is breaking due to stress. The cap plastic could be brittle, but trying to muscle it off will attribute to such damages too.

I know when this topic first came up when I had my prior 2016 - never had an issue with the coolant cap in 2.5 years of daily use ownership. My 2018 now has 39k on it, no issue with coolant cap.

 

[Skye]

but I am now thinking many of these broken coolant caps are happening because owners are not "pushing down" on the cap first, before trying to twist it off.

Could definitely be some truth to that. Coupled with the brittleness, the whole thing falls apart.

If you look at the cap, it looks like a regular twist-off cap. It doesn't look like a traditional radiator cap. Nothing on the cap references to push down to remove it.

I reference listening for the "click" above, because that caught me. The first time I took the cap off and put back on, I thought I had tightened enough. The second time, I gave it one last nudge, and heard the click, which is supporting the need to later push back down to take back off. I wonder how many others have been tightened, but not necessarily secured. Or if doing that before OK, leads them to never consider pushing down.

I'm sure we're not the only ones. I wonder what other Ford models and owners experience the same issue.

 

[Skye]

Thanks for the insight. Checked mine this morning.

1. Push down, slowly unscrew and remove cap.

2. Take 1 Q-tip, douse with Silicone spray.

3. Apply Q-tip to both rubber O-rings and seating (flat) surfaces.

4. Re-attach cap.

5. Repeat steps 1-4 one more time. Be sure to listen for the "click" to ensure cap is on.

A bump for awareness.

I'd been thinking of this topic and yesterday seemed like a great time to check and reaccomplish.

 

[ice445]

I've seen this on a few cars now, it doesn't matter at all if you push down while you twist the cap off, so I'm not sure where that comes from. Literally doesn't do anything, there's no spring preload to compress or anything like that (the only spring is for the overpressure bleed off). Pushing down is just pushing the cap into the reservoir threads. It's simple to test this for yourself, if you lube the o-rings and then try with and without pushing, you can see that there's zero difference in how it feels going on and off. I could maybe see pushing on it slightly helping relieve the stuck sealing surface, but other than that it's not some official process that you have to do.

They only get tight because the o-rings seize on the plastic after a certain amount of heat cycles. Lubing with silicone grease makes a huge difference, even with a new cap and a new reservoir. Lubing my brand new cap made it go on so easy it took almost no effort, same with removal.

 

[RagmopInKona]

A little grease on the

Put some silicone grease on the O-rings to help prevent the cap from seizing up.

This is the way, you'd not put an oil filter on without a touch of oil on the flat o ring gasket and hope it turn next time.

 

[Cory S]

I feel that it’s the incompatibility between the two types of thermoplastics binding during threading after some time. Causing people to overtighten the cap eventually. My cap threads on very tight the whole way. So tight that when I feel the resistance get even tighter, I stop there. I never get to the clicking part. I’m thinking the cap itself shrinks ever so slightly over the years, or the expansion tank threads swell.

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