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Still Over-Heating...High Pressure in Cooling System; Cooling System
Topic Started: Nov 18 2016, 06:56 PM (413 Views)
Jim R Caretaker
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Is this thing on...
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My 1998 Chevy Metro is over-heating still. I've replaced the Radiator Cap, Thermostat, Head-Gasket...

I really love my Metro but this project is kicking my butt. Anybody have ideals what I'm doing wrong.

Thanks in Advance
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Bjetmech
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When you got it all back together did you burp the cooling system? There are a few high points like the throttle body that are higher than the radiator. I usually just let the car idle in the driveway until the engine warms up and pull the heater hose off the TB and let it flow for about 5-10 seconds.

Also how old is the radiator, if its plugged up in places it will affect how it cools the motor.
Edited by Bjetmech, Nov 18 2016, 07:17 PM.
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freegeo
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Could be a number of things. Clogged radiator. Water pump. Head gasket that has failed.


How hot is it getting on the gauge. Have you verified the coolant and engine is actually overheating and it is not a gauge error problem.
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Jim R Caretaker
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Looking better guys, flushed the system, tested the new thermostat did not respond just right so replaced that. Anyway, thanks for all your tips and pointers.
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MarkyMayhem


Jim R Caretaker
Nov 19 2016, 05:17 PM
Looking better guys, flushed the system, tested the new thermostat did not respond just right so replaced that. Anyway, thanks for all your tips and pointers.
Out of curiosity - T-stat failed closed, right?
Other than that I dont see how you could presurize the system unless the block or head has a crack. Thinking about a metro in my noggin to determine how a stuck t-stat would presurize things... Coolant bubbled out the overfliw i guess? Did it do it only when overheating?
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MR1 Kingsbury
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Exp. builder/rebuilder

an air bubble at the Tstat can cause it. engine overheats the coolant under pressure from the waterpump, and the Tstat don't open cause it aint wet and hot. then when you shut it off it backflushes searing hot coolant through the pump and radiator pressurizing that as well.
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t3ragtop
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Turbo3 and Twincam Tweaker

don't overlook the new radiator cap. the later model radiators have radiator necks that are different from the earlier production cars. those cars take a different radiator cap.

if the stopper for the cap doesn't fit the neck it can't open properly to vent to the overflow tank.
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Jim R Caretaker
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Thanks guys for all the help. She's running fine now. I just reviewed things.

I did by a new Rad. Cap, however the new cap was 16 lbs. I put the old one back on 13 lbs. appears to be working fine.

I tested the thermostat in some boiling water 212 degrees right, It should respond to that being set at 195. I was not happy with the response. replaced it.

Running cool now, where it has always run.
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