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Old 05-31-2007, 03:04 PM   #1
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Default bad radiator cap?

after i drive for a bit and the car fully warms up, i'm doubting that the radiator cap is allowing coolant to flow into the overflow bottle. the upper radiator hose is REALLY stiff, and the overflow tank is still at "full cold" after i park from a drive. i have never had a cooling system problem before with this car. i also don;t have tools to check the rad. cap. any ideas? anyone else have a similar problem?

edit: i know a new rad. cap is cheap, should i just go buy one and see how it treats me?
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Old 05-31-2007, 03:34 PM   #2
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Check the level of coolant in the radiator. The cap should hold ~16psi in the system before allowing flow to the overflow.
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Old 05-31-2007, 09:00 PM   #3
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I usually only get 1/2 inch or so rise in the overflow tank. You should have the cap pressure tested. It could be clogged or as Bill said check that the level in the radiator is up there.
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Old 05-31-2007, 10:46 PM   #4
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I actually just found out that my disappearing coolant was due to my radiator cap only holding 5 psi It'* cheap anyway, worth a shot...
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Old 06-01-2007, 11:16 AM   #5
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yes, the radiator is full. it concerns me how stiff the hoses get, i'm afraid if pressure builds too much that they will burst.

is it supposed to be 16 psi? my current cap says 15 psi IIRC

i did take off the cap and look at it and the little (i don't know what it'* called, the thing the pops out to let coolant back into the radiator) felt loose, it was jiggling around a bit.
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Old 06-01-2007, 01:36 PM   #6
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The jiggle is normal.. to a degree.

15psi huh.. oops. I musta shot from the hip and remembered one pound off.
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Old 06-01-2007, 01:47 PM   #7
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If the problem isn't due to the radiator cap, also check to make sure that the radiator'* opening for the connection to the overflow hose is unobstructed, and that the overflow hose is unobstructed. I don't how much pressure would buildup if either of these was obstructed, but it'* worth checking.
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Old 06-04-2007, 10:24 AM   #8
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well i replaced the rad cap this weekend (ugly hexagonal autozone cap) with a 16 PSI. The hoses still feel really stiff (although i only checked once). I thought of the overflow tube thing while i was checking it, so i blew into the overflow tank to push coolant out into the rad, and it worked. so now i'm stumped.

wth!
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Old 06-04-2007, 10:56 AM   #9
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15-16psi isn't easy to squeeze. Are you only going on the fact that it'* tough to squeeze?
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Old 06-04-2007, 11:12 AM   #10
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that, and the overflow tank looks completely unchaged. ususally, if i try to squeeze the hose, you can see water flowing into it, but it'* not doing that as much.

i'll give it another look next time i let the car warm up....maybe i'm imagining things...
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