what happen when the radiator cap gone bad?? - CamaroZ28.Com Message Board


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Old 09-12-2003, 12:18 AM   #1
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what happen when the radiator cap gone bad??

can a bad radiator cap causes the temp. to rise up slowly?? just wondering if that's the cause of my rising temp when i turn my AC on....

thanks
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Old 09-12-2003, 12:45 AM   #2
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The system won't be properly pressurized if the cap isn't good. This may lead to overheating issues, but I really don't see why not just replace it? I mean, it's like a $3 part...
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Old 09-12-2003, 12:52 AM   #3
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It's fairly normal for the engine temp to rise a little with the A/C on due to the load.

If your cap is bad, that can also cause overheating. If your cap is original, it wouldn't hurt to change it out, they're pretty cheap.
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Old 09-12-2003, 12:54 AM   #4
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If the cap is not keeping adequate pressure on the coolant, its going to let coolant into the overflow tank. This one reason you should replace a faulty coolant level sensor and not just unplug it. If you keep topping coolant off and it never levels off and you know its not a headgasket or leak, its likely the cap!

Ryan
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Old 09-12-2003, 08:46 AM   #5
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thanks for the info.....

i will replace it today. also my low coolant sensor is bad too, it lights off sometimes, but i always check my coolant level, and it always full.....
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Old 09-12-2003, 12:52 PM   #6
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Quote:
It's fairly normal for the engine temp to rise a little with the A/C on due to the load.
Wrong, for LT1's. In hot climates turning the AC on turn both fans on and the temps. go down not up.
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Old 09-13-2003, 12:19 AM   #7
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I've had my car long enough to know how it runs. It typically goes up 10-15 degrees.
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Old 09-13-2003, 12:58 PM   #8
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AC takes my car temps down. Turns the fans on sooner in traffic... keeps temp around the 1/4 mark.
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Old 09-13-2003, 02:28 PM   #9
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If you have AutoZone out there you can borrow a cap and radiator pressure tester.
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Old 09-13-2003, 02:48 PM   #10
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Quote:
Originally posted by toby360
AC takes my car temps down. Turns the fans on sooner in traffic... keeps temp around the 1/4 mark.
that's what happen before my waterpump took a dump on me. i replace the waterpump, and reprogram my cooling temp to 185* and BoOm.... now as soon as the AC's on. the temp is crawling up....

what do i have to do???

Quote:
Originally posted by Compstall
It's fairly normal for the engine temp to rise a little with the A/C on due to the load.

the temp. rising with the AC on never happen before. usually, as soon as i turn on the AC, the temp goes down to 1/4 mark. but now, it's creeping up slowly.....

maybe i need to reprogram my fans not to shut off untill i reached the speed of 45 MPH


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Old 09-13-2003, 04:12 PM   #11
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Quote:
Originally posted by toby360
AC takes my car temps down. Turns the fans on sooner in traffic... keeps temp around the 1/4 mark.
Im with Brent on this one....my temp goes up 10-20* when the ac is on...now befor I started using the 160* tstat and reprogramed the fans the reverse was true.
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Old 09-13-2003, 04:50 PM   #12
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Originally posted by gb95zconv
Im with Brent on this one....my temp goes up 10-20* when the ac is on...now befor I started using the 160* tstat and reprogramed the fans the reverse was true.
You guys that are having this problem have other issues in your cooling system if this is truly what is happening. I found out when mine was doing it that I needed to do a heater core flush. Since the flush, my temp goes down, and stays steady.
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Old 09-13-2003, 06:21 PM   #13
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My temp goes up too when the A/C is on. And when it's not, my car runs cool.

I checked with a logger, and you can see that the A/C adds load onto the engine. Just at idle it'll go from ~30kpa to about 38-39kpa. That will make the engine run hotter, no doubt, even if the fans come on.
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Old 09-13-2003, 06:31 PM   #14
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Quote:
Originally posted by toby360
AC takes my car temps down. Turns the fans on sooner in traffic... keeps temp around the 1/4 mark.
Mine stays at about the 1/4 mark as well with AC on, if I turn it off the temp goes to about 1/2, more if I'm in traffic.
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Old 09-13-2003, 07:55 PM   #15
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My radiator cap lost complete pressure within 5 seconds on the cap tester and it DID CAUSE A HIGHER TEMPERATURE!! I put on a new cap and like everyone else now with 160 t-stat, watter wetter, new radiator and waterpump, I usually do not pass the 185 mark unless I turn the car off, back on, then off again, then back on. I wish i had replaced the cap before I did all that stuff though, andyes the temp should be slightly higher with the ac on, cause it will send heat into the engine bay.
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