LT1-LT4 Modifications 1993-97 Gen II Small Block V8

Overheating problems

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Old Feb 26, 2007 | 09:37 PM
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Default Overheating problems

Alright, yet another problem.. Within 10 minutes of starting the car, it hits about 220 before I shut it down. Replaced the thermostat twice, water pump seems to be good (electric). Let it idle for a couple minutes with the radiator cap off, and there are no bubbles or anything. By the time the temp hits 170, the coolant starts to rise, and will overflow. Any ideas? Fans are on and working. Tried flushing the system, no change. Out of curiousity, when its running, shouldn't coolant be flowing from the line coming from the back of the heads? Seem to remember it doing that before, and its not now. Thanks in advance!
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Old Feb 26, 2007 | 09:42 PM
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i hope your making use of the bleeder screws, first of all what seems to work fairly well is start it up with the radiator cap on, let some pressure build and pop the bleeders open until coolant starts coming out on both of them

it sounds like you've got an air pocket and coolant isn't circulation (obviously if it gets hot that quick)
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Old Feb 26, 2007 | 09:51 PM
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Ya, bleed it a lot with the screws.. nice stream of coolant flying out.. forgot what direction its aimed on the top of the water pump... got shot in the stomach. Good amount of pressure.
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Old Feb 26, 2007 | 10:02 PM
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cover the opti to please
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Old Feb 26, 2007 | 10:13 PM
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got the MSD opti.. seems to be doing ok. Also, making sure no water really gets that far. Not to go off subject on my own thread, but does anyone know how well the MSD opti does against water? Just curious. Again, thanks for the help.
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Old Feb 26, 2007 | 10:42 PM
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Tried bleeding it again.. can get a 4 foot stream out of those bleeders... gets to 220+ in about 4 minutes now, and cools down to 180ish in 3 minutes.. back up to 220+ in 4 minutes after starting it again. This is really annoying. Any other ideas? Radiator cap is cold. Have one that allows you to release pressure with the little tab... bump the tab at all, and can hear it gurgle. Any thoughts?
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Old Feb 28, 2007 | 11:15 PM
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Alright, still having the same problem.. any ideas?
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Old Feb 28, 2007 | 11:36 PM
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I have the same proble but only when i have it warmed up if i sit at a light too long or stop and go it goes past 220 and then down and right back up i figured i was supposed to do that i just bought my car a month ago
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Old Mar 1, 2007 | 01:09 AM
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220 is normal operating temperature. IIRC the fans kick on around there to regulate the temp once it hits 220 hence why it drops back down when it gets to 220ish.

have you tried flushing the coolant system?
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Old Mar 1, 2007 | 01:35 AM
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I had the same type of problem so i installed a manual switch and when it starts gettin to warm for my liking i flip it on...works great for me
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Old Mar 1, 2007 | 11:05 PM
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i currently have the exact same prob!!! i just recently took it to a shop and they said that the head gaskets were the problem...and then they preceded to quote me $3,100 so know i have to tow it home 2hours away and work with my pops race machanic...should save a buck or two haha...who knows maybe hes got some extra race parts to rebuild the top end with...I feel your pain tho......
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Old Mar 1, 2007 | 11:21 PM
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Ya, I have the fans on high as soon as I start the car. Temp only drops when I shut the car off. I've been thinking its the head gaskets, but praying its something else. Anything else. lol. Don't really have the time to work on it, or the money to have someone else. Right now the car is 200 miles away.. can only work on it on the weekends. Guess maybe this weekend I'll get one of those U-Haul trailers and bring it up here to Seattle. Might be able to work on it a little more then. lol
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