Overheating Troubleshooting
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Joined: Mar 2008
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Overheating Troubleshooting Guys, This is my first post, and I appoligize for it being a question, but man I'm getting myself pretty much in a fuss here.
I purchased a '01 z28 a few days ago.
The car ran good for an hour or so then the Check engine light came on. Turns out that both cats are clogged (What Autozones code read said). Shortly there after the car started over heating pretty badly. The temp will usually hover around 210 for a few minutes, and then it'll spike up to redline at which point I have to shut the car off let it cool and limp it to somewhere. I have not driving it much since the over heating issue.
I replaced the thermostat thinking that its not opening once the car heats up. No change.
i replaced the Coolant Temp gauge on the #1 cylinder, again no change.
I replaced the water pump and once again, no change.
While I was changing the water pump I took a water hose to the Radiator and put water into the cap, plugged off both the upper and lower hoses and had good water flow through both ends of the radiator.
As the car overheats, eventually I lose hot air coming outa the heater core. So I assume theres a fluid flow problem somewhere. Also when I changed out the Coolant temperature, the copper end that goes into the block was dry, normal?
What would be the next step for figuring out the problem. From what I can tell none of the hoses are kinked or blocked. The radiator is having good flow. I would think the Cats could be causing the overheat, but I dont see how it would cause the lack of hot fluid to the heater core.
I notice no leaking of coolant anywhere, nor steam spray.
Please help!
I purchased a '01 z28 a few days ago.
The car ran good for an hour or so then the Check engine light came on. Turns out that both cats are clogged (What Autozones code read said). Shortly there after the car started over heating pretty badly. The temp will usually hover around 210 for a few minutes, and then it'll spike up to redline at which point I have to shut the car off let it cool and limp it to somewhere. I have not driving it much since the over heating issue.
I replaced the thermostat thinking that its not opening once the car heats up. No change.
i replaced the Coolant Temp gauge on the #1 cylinder, again no change.
I replaced the water pump and once again, no change.
While I was changing the water pump I took a water hose to the Radiator and put water into the cap, plugged off both the upper and lower hoses and had good water flow through both ends of the radiator.
As the car overheats, eventually I lose hot air coming outa the heater core. So I assume theres a fluid flow problem somewhere. Also when I changed out the Coolant temperature, the copper end that goes into the block was dry, normal?
What would be the next step for figuring out the problem. From what I can tell none of the hoses are kinked or blocked. The radiator is having good flow. I would think the Cats could be causing the overheat, but I dont see how it would cause the lack of hot fluid to the heater core.
I notice no leaking of coolant anywhere, nor steam spray.
Please help!
Thread Starter
Registered User
Joined: Mar 2008
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Yes I have coolant... I know that question had to get asked 
And I took both hoses off and water flows well through the radiator.
I've heard some issues about air bubbles? Thats certainly possible I supppose, but how would I diagnose that and how would I get them out. and is it really common? or one of those off the wall possibilities
And I took both hoses off and water flows well through the radiator.
I've heard some issues about air bubbles? Thats certainly possible I supppose, but how would I diagnose that and how would I get them out. and is it really common? or one of those off the wall possibilities
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well my first attempt is going to be to bleed the coolant lines of air.. that sounds feasible I think, as I can't think of any other reason to have the pump all of a sudden apparently not pumping water.
If I wanted to do this how should I. If I've got a massive air bubble in the radiator or intake line to the water pump.. First question I guess is whats the diretion of flow, does it go through the thermostat first then through the engine, then through the pump back to the radiator?
Should I drain the radiator completely, then pull off the Upper hose and fill via that way? Should I fill it the rest of the way through the radiator cap then?
If I wanted to do this how should I. If I've got a massive air bubble in the radiator or intake line to the water pump.. First question I guess is whats the diretion of flow, does it go through the thermostat first then through the engine, then through the pump back to the radiator?
Should I drain the radiator completely, then pull off the Upper hose and fill via that way? Should I fill it the rest of the way through the radiator cap then?
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Verdad Gallardo well my first attempt is going to be to bleed the coolant lines of air.. that sounds feasible I think, as I can't think of any other reason to have the pump all of a sudden apparently not pumping water.
If I wanted to do this how should I. If I've got a massive air bubble in the radiator or intake line to the water pump.. First question I guess is whats the diretion of flow, does it go through the thermostat first then through the engine, then through the pump back to the radiator?
Should I drain the radiator completely, then pull off the Upper hose and fill via that way? Should I fill it the rest of the way through the radiator cap then?
If I wanted to do this how should I. If I've got a massive air bubble in the radiator or intake line to the water pump.. First question I guess is whats the diretion of flow, does it go through the thermostat first then through the engine, then through the pump back to the radiator?
Should I drain the radiator completely, then pull off the Upper hose and fill via that way? Should I fill it the rest of the way through the radiator cap then?
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Joined: Dec 2005
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From: NW burbs of Chicago
Here is one to try. Clean the front outside of the radiator. You could have dirt, newspaper, plastic bags, bugs, birds, leaves, honda civics, mustangs and all kinds of other **** clogging the air flow through the radiator.
Thread Starter
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Joined: Mar 2008
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Well just to end this thread for anyone who uses the search feature. It turned out I had air bubbles in the coolant system. I ran the car w/o the coolant cap on for awhile. Let it cool down, then re added fluid. Made sure the heater was on full while I was doing it and walla. Problem solved. Thanks guys
Glad to hear you solved the problem man..and also it's great that you came back and updated it.Not many people do that and you end up getting tons of posts with no answers when you do a search!
Good job man!
Good job man!
Teching In
Joined: Jun 2008
Posts: 3
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Guys, This is my first post, and I appoligize for it being a question, but man I'm getting myself pretty much in a fuss here.
I purchased a '01 z28 a few days ago.
The car ran good for an hour or so then the Check engine light came on. Turns out that both cats are clogged (What Autozones code read said). Shortly there after the car started over heating pretty badly. The temp will usually hover around 210 for a few minutes, and then it'll spike up to redline at which point I have to shut the car off let it cool and limp it to somewhere. I have not driving it much since the over heating issue.
I replaced the thermostat thinking that its not opening once the car heats up. No change.
i replaced the Coolant Temp gauge on the #1 cylinder, again no change.
I replaced the water pump and once again, no change.
While I was changing the water pump I took a water hose to the Radiator and put water into the cap, plugged off both the upper and lower hoses and had good water flow through both ends of the radiator.
As the car overheats, eventually I lose hot air coming outa the heater core. So I assume theres a fluid flow problem somewhere. Also when I changed out the Coolant temperature, the copper end that goes into the block was dry, normal?
What would be the next step for figuring out the problem. From what I can tell none of the hoses are kinked or blocked. The radiator is having good flow. I would think the Cats could be causing the overheat, but I dont see how it would cause the lack of hot fluid to the heater core.
I notice no leaking of coolant anywhere, nor steam spray.
Please help!
I purchased a '01 z28 a few days ago.
The car ran good for an hour or so then the Check engine light came on. Turns out that both cats are clogged (What Autozones code read said). Shortly there after the car started over heating pretty badly. The temp will usually hover around 210 for a few minutes, and then it'll spike up to redline at which point I have to shut the car off let it cool and limp it to somewhere. I have not driving it much since the over heating issue.
I replaced the thermostat thinking that its not opening once the car heats up. No change.
i replaced the Coolant Temp gauge on the #1 cylinder, again no change.
I replaced the water pump and once again, no change.
While I was changing the water pump I took a water hose to the Radiator and put water into the cap, plugged off both the upper and lower hoses and had good water flow through both ends of the radiator.
As the car overheats, eventually I lose hot air coming outa the heater core. So I assume theres a fluid flow problem somewhere. Also when I changed out the Coolant temperature, the copper end that goes into the block was dry, normal?
What would be the next step for figuring out the problem. From what I can tell none of the hoses are kinked or blocked. The radiator is having good flow. I would think the Cats could be causing the overheat, but I dont see how it would cause the lack of hot fluid to the heater core.
I notice no leaking of coolant anywhere, nor steam spray.
Please help!
Having similar problems,reading threads suggested tune up, or possible cat maybe clogged. I will attempt to get air out of system. As long as I am moving 55+ it all good but if I stop at a light temperature is rising fast.