coolant cap problem.

[None2Slow]

Went to check my coolant level the other morning and it was low. I went to remove the cap to top it off and after a couple turns, it became really tight. Turned it a bit more and it loosened up. Found this once I get everything out. Anybody else have this happen?

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[Cobra Jet]

You’re not alone:

https://www.mustang6g.com/forums/th...-cap-can-i-drive-it-home.116245/#post-2444879

https://www.mustang6g.com/forums/th...parated-on-overflow-tank.118925/#post-2497827

I’ve heard that the problem could be related to how people are trying to remove the cap. Most obvious is it should be removed when engine is cold.

Also to note, the proper way to remove the cap is not only does it have to be twisted off, but also pushed down simultaneously to remove. If the user is putting muscle into just twisting it off, it’s going to break.

Think of the newer style cap as the older style rad caps on the actual radiator tanks - push down and turn. Or think of it as a childproof tamper-resistant pill bottle top.

 

[None2Slow]

It was cold and I just unscrewed it. Once I had the top off, the other parts were "stuck". I had to heat them up with a propane bottle and pry them out with vise grips. it was a real pain, but a new cap was only $7.49. Never had a problem like that before. I have a 1999 F350 with 197,000 miles that has a similar setup and never had a problem like this. Anybody experience this? Should I look at maybe buying an aftermarket cap?

 

[Ghost50]

When I changed my tank from stock to Mishimoto I noticed the cap was a little tougher to get off. I’d read on here about the same issue you had so I bought two new caps on Tasca Parts just to have in case mine broke when I was removing it.

 

[GT Pony]

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

 

[None2Slow]

I wonder if anti seize would work? I mean I got both, but it's in the name.

 

[GT Pony]

I wonder if anti seize would work? I mean I got both, but it's in the name.

Silicone grease won't hurt rubber. Not sure about anti-seize that's meant for metal fasteners.

 

[None2Slow]

I didn't think about that. Thank you for the heads up.

 

[15mustang]

When I changed my tank from stock to Mishimoto I noticed the cap was a little tougher to get off. I’d read on here about the same issue you had so I bought two new caps on Tasca Parts just to have in case mine broke when I was removing it.

This is a common problem with broken caps. The easiest way I found to remove the broken half is to superglue (yes superglue) the top of the cap to the broken bottom half. Just be careful you don't super glue it to the reservoir. With superglue you'll be able to pull it right out, without risking broken plastic in the antifreeze.

 

[15mustang]

You’re not alone:

https://www.mustang6g.com/forums/th...-cap-can-i-drive-it-home.116245/#post-2444879

https://www.mustang6g.com/forums/th...parated-on-overflow-tank.118925/#post-2497827

I’ve heard that the problem could be related to how people are trying to remove the cap. Most obvious is it should be removed when engine is cold.

No its just a defective cap design.

 

[Cobra Jet]

Thanks to @15mustang and his way of removing a faulty or broken coolant cap to avoid further frustration:
https://www.mustang6g.com/forums/th...an-i-drive-it-home.116245/page-3#post-3560889

 

[Deleted member 35644]

Happened to me the first time I took the cap off my convertible. Bought a new one, put a little oil on the o-ring and installed it. Never an issue since.

 

[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.

 

[Chef jpd]

Just because I am bored, I went and tried the cap on my 2020.
Cap has never been removed since new.
Popped right off, no issues. It seems to have been well lubricated from the factory.
I pulled the O ring and marine greased it anyway.
Went back on like buttah.

 

[jblue]

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.

Good info. Just did that to mine, as it's almost a year old. Easy to perform like once a year. That is what I really like about this forum. I have learned many things/tricks for different things that I would not have known about Mustangs! Thank you.

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