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Discussion Starter #1
Hey guys,

Weirdthing happens on my 1st gen.....i put a new, aftermarket (but well done) radiator in, everything fits nice, just one problem.
The radiator cap closes like on the old one, BUT when it´s closed, you still can push the water from the radiator into the coolant reservoir by squeezing the upper hose.
So it won´t build up any pressure.

Is that normal or would it start to boil cause of the missing pressure?

Thanks a lot,

Greetings
Kevin
 

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KOG
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May be the wrong cap, but some of them don't have a spring on the return valve which will let it do what you're saying and will still seal under pressure as engine heats.
 

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Discussion Starter #3
It´s still the original cap, i tried to add another seal / o ring, hope it works.... but i can´t find any other issue...
 

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Super Moderator
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The coolant return poppet valve (the one in the center of the rubber washer) should allow coolant to flow from the reservior to the radiator, but coolant should not flow from the radiator to the reservior by squeezing the upper hose. Debris in the coolant like gasket shaving material or stop-leak or anything that floats to the top of the coolant can cause this poppet not to seal well. The coolant must be clean.
 

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Discussion Starter #5
Thanks for info!

I cleaned out the cap, looks like new, i also cleaned the rubber gaskets with some silicone spray, all nice and soft.
I have to flush the cooling sytsem first with some special radiator cleaner (Liqui Moly), then i try it again...hope it works right
 

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In my experience its good to go ahead and replace the cap when you change something like the radiator. My original cap for whatever reason wasn't getting the job done and the car would lose the coolant when it got hot, but wouldn't let it back in when it cooled off. Replacing the cap fixed that right up.
 
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