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Old Jul 9, 2021 | 01:10 PM
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Ok I have a question. I drove my 89 c4 to town thus am to run sum errands. Lot of start and stops. When I got home and got our and shut the door I heard like something boiling! So I unlocked and popped the hood and my radiator and the over flow container was very hot!! My running temp was at about 250. Is this normal??
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Old Jul 9, 2021 | 02:49 PM
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Hopefully it'll be something dumb like a bad thermostat or radiator cap. Or maybe debris stuck between the radiator. Or your fan not running. Or a leaking/bad hose.

If you need to refill coolant, fill it directly into the block before installing a thermostat.

Check all of that first.

Definitely do not put anything out of a bottle into your coolant system that claims to seal leaks.

What's your oil look like? When did you last change your coolant and flush the system?

Do you have a pressure tester? Or access to one?

Last edited by Natty C; Jul 9, 2021 at 02:57 PM.
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Old Jul 9, 2021 | 05:25 PM
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[QUOTE=Kmoylan;1603706542].......... my radiator and the over flow container was very hot!! My running temp was at about 250. .....QUOTE]

Not normal. Symptoms of a ruptured head gasket allowing exhaust gases into the coolant. Not saying that is your problem, just alerting you to symptoms. Most auto stores have a test kit to determine if there are exhaust gases in the coolant. Simple test.
Over-heating is due to insufficient coolant, blocking coolant flow, air flow, or both, or ruptured head gasket.

I'm betting the siphon event is not occurring (expanded coolant moving to over-flow container when hot,
and not returning to reservoir during cool-down). Any breach in the cooling system will cause the same no-siphon condition, so it doesn't have to be a ruptured head gasket. Insufficient coolant will cause over-heating. One item usually over looked is the gasket for the radiator cap. Due to the excessive torque required to remove the cap, the gasket can be torn or deformed allowing air to enter, and defeat the siphon.

If coolant is continually moving to the over-flow container, and not returning to the reservoir, over-heating will occur.

Last edited by don hall; Jul 10, 2021 at 08:48 AM.
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Old Jul 9, 2021 | 08:38 PM
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What's your oil look like?

As natty C said this is one thing you should check before restarting the car. Since you are not sure how hot it was before you checked or for how long there could be a head gasket problem. Clear oil is what you can hope for. L98 engines are very durable but aluminum heads can warp but fortunately not often.

Follow all of the other suggestions to remedy this issue before driving it again and keep an eye on the temperature guage.
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Old Jul 9, 2021 | 09:53 PM
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I had the same thing happen to me this week in my 87.It turned out to need burped and a new radiator cap
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Old Jul 14, 2021 | 12:01 PM
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Hi Everyone,
I am a new owner of a 1992 corvette convertible and I notice a strong gas smell inside the car....I checked for gas line leaks but didn't find anything. Does anyone have any thoughts on why this is happening? Thanks
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Old Jul 14, 2021 | 12:19 PM
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Check to see if the cap is on tight and venting properly
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Old Jul 14, 2021 | 04:24 PM
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Originally Posted by davidwa
Hi Everyone,
I am a new owner of a 1992 corvette convertible and I notice a strong gas smell inside the car....I checked for gas line leaks but didn't find anything. Does anyone have any thoughts on why this is happening? Thanks
Congrats on your new car. Your question deserves its own thread where you may receive more responses.
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Old Jul 14, 2021 | 06:23 PM
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[QUOTE=don hall;1603707852]
Originally Posted by Kmoylan
.......... my radiator and the over flow container was very hot!! My running temp was at about 250. .....QUOTE]

Not normal.
I'm betting the siphon event is not occurring (coolant not overflowing to expansion tank when hot and not returning to radiator during cool-down).
FIFY, more clear.
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Old Jul 14, 2021 | 06:25 PM
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Originally Posted by davidwa
Hi Everyone,
I am a new owner of a 1992 corvette convertible and I notice a strong gas smell inside the car....I checked for gas line leaks but didn't find anything. Does anyone have any thoughts on why this is happening? Thanks
Fuel evaporation system could have a major leak. A scanner should be able to identify this.
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