# Loose coolant tank cap?



## sx sonic (Nov 25, 2013)

It should be like most caps/threaded fasteners, snug when fully tightened and then pretty easy to spin once broken free.

Snug it up and check a few hundred miles later to make sure its not working loose.


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## Starks8 (Jul 20, 2011)

Unfortunately, IIRC I think quite a few other members have complained about this very same thing.


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## rcclockman (Jan 16, 2012)

its weird, when its fully tight, it just stops, it doesnt feel like its getting tight, then stops.. it has like zero friction from when you just put it on till it fully all the way on...


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## NickD (Dec 10, 2011)

Not sharing this problem and can only wonder with GM's multiple sourcing for the same parts, like AC compressors, heater cores, water pumps, etc., are not manufactured to the required standards. My drivers' side window weather stripping was sure a piece of crap.

But the cap on the reservoir fits and screws on very tightly, has to, and has seal well. Thermostat operates at above the boiling point of water and your coolant will steam off.

Would take it back to your dealer and insist on getting some decent. Ha, wanted to see that new weather strip before they put it on, new one had the correct gap size on it. No sense in replacing one piece of crap with another. FDA was very strict requirements on screwing a a cap for throwaway food containers. If they didn't, we would be dying of food poisoning.

Same can happen with this reservoir, located right below the fresh air intake, coolant fumes are also killers, can live without kidneys.


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## Robby (Mar 1, 2013)

IMO, compared to the old style 2 step pressure cap, yes.....feels, I guess, loose is a fair description.

But, as long as the system holds pressure there is no concern.....this cap uses a 'O' ring seal and there is little resistance to removing or re installing it.

Rob


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## obermd (Mar 3, 2012)

Mine is loose once I break the "seal". It does take some force to break the "seal" and I have never seen it move on its own.


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## NickD (Dec 10, 2011)

Could misread the OP's response assuming was a defective cap or a reservoir.

Mine also came loose from the factory. Topped the reservoir with Dexcool to the full cold line, used a black magic marker over that line so I could see it, tightened the cap and haven't touched it since. This was over two years ago and the cold fluid level is right where I left it. 

Maybe that guy on the line putting on caps all day has a tired hand. They use computerized torque impact wrenches for almost everything else. Good question if they have on for this cap.


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## rcclockman (Jan 16, 2012)

Exactly, there is no breaking loose of the seal like you say...Its the same resistance from fully tight to fully unscrewed...It does hold pressure so I guess that's how it is weird... I could take my pinky finger and unscrew it from fully tight....


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## Dale_K (Jul 16, 2011)

When I looked at my cap it seemed that the seal is created by an o-ring around the "shaft" of the cap that seals against the inside of the coolant tank neck. I don't think it seals like an old fashioned cap with a flat gasket on the underside of the cap. I'm no expert, so I could be wrong.


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## Robby (Mar 1, 2013)

Dale_K said:


> When I looked at my cap it seemed that the seal is created by an o-ring around the "shaft" of the cap that seals against the inside of the coolant tank neck. I don't think it seals like an old fashioned cap with a flat gasket on the underside of the cap. I'm no expert, so I could be wrong.


Your observation is correct.

Rob


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## tdc (Jan 24, 2014)

Hi NickD, (and fellow members), I'm having the same symptoms as rcclockman above (thread originator). I just replaced my coolant reservoir cap with a new one (GM, p/n: 13502353) [2012 Cruze LS, Auto, 32K miles]. Reason: my coolant level was at the top of the min vertical mark on bottle. So, wanting to add a little coolant, tried unscrewing the (orig) cap. It was so hard to turn, the top/hand portion separated from the inner portion (having the o-rings/spring_valve/seals), leaving this 'plug' inside the reservoir's bottle neck. It was difficult getting that plug out. I ended up using pliers, braking it in pieces to get it out. That's how tight it fit & sealed. Now, the new cap, (GM part), is so so loose fitting, I'm wondering if it will hold 20 psig. I can turn it way too easily, in my opinion (as rcclockman also commented). Any and all comments & advice welcomed. Thank you so much.


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