Overheating problem with 92 vette
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Joined: Mar 2005
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From: Nashville TN
Overheating problem with 92 vette
Ok, i got a 92 LT1 vette and i'm having a little problem with the overheating thing.
If it's parked and running it will just get hotter and hotter
If i'm going down the highway with the A/C off it will go down to normal range
If i'm going down the highway with the A/C on, it will get hotter and hotter until the coolant starts to boil
Things i've checked....
1. The radiator is a little dirty, i am going to clean it real good this weekend.
2. Drivers side fan will turn on, but the passenger side one won't. (bad motor or what?)
3. It has coolant.
Anything else i should be checking?
If it's parked and running it will just get hotter and hotter
If i'm going down the highway with the A/C off it will go down to normal range
If i'm going down the highway with the A/C on, it will get hotter and hotter until the coolant starts to boil
Things i've checked....
1. The radiator is a little dirty, i am going to clean it real good this weekend.
2. Drivers side fan will turn on, but the passenger side one won't. (bad motor or what?)
3. It has coolant.
Anything else i should be checking?
Safety Car
Joined: Sep 2002
Posts: 4,971
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From: The reason time exists is so everything doesn't happen at once
How much coolant does it have? This system takes about 4 1/2 gallons. (Actually 17.8 quarts). Make sure you "burp" the system. Let the car cool down. Then remove the pressure cap from the top recovery tank. Start the car and let it run. As the coolant level in the tank goes down add more coolant. Continue doing this until the top tank stays full, then top off the lower tank if necessary.
Le Mans Master
Joined: Dec 2000
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From: San Diego, Ca
Both fans should come on when the a/c is on - speed below 40 mph. If the secondary fan isn't coming on, swap relays (if such is possible) and see if does. If so, replace the relay. If not, the fan relays (for a/c) are controlled by a pressure switch on the high pressure a/c line. It's a thermistor with a 5 volt reference from the PCM and the return voltage increases as the a/c pressure rises. Each volt on the return circuit is about 100 psi. The PCM will ground the fan relays as long as it sees about 150 psi or 1.5 volts. Best to troubleshoot it with a scanner which will show you the voltage and most scanners will translate that into pressure.
At cruise , a/c and the cooling system will work as designed without the fans so the PCM shuts them off. If it's overheating at speed with the a/c on, airflow maybe restricted through the condensor or the a/c system may be plugged up creating excessive pressures (and the higher the pressure, the more heat thrown off by the condensor). Can't imagine your a/c is functioning very well with only one fan at idle and the enging overheating at speed. Might be better to stop in an a/c shop for a quick pressure check. Should be less than $50.
At cruise , a/c and the cooling system will work as designed without the fans so the PCM shuts them off. If it's overheating at speed with the a/c on, airflow maybe restricted through the condensor or the a/c system may be plugged up creating excessive pressures (and the higher the pressure, the more heat thrown off by the condensor). Can't imagine your a/c is functioning very well with only one fan at idle and the enging overheating at speed. Might be better to stop in an a/c shop for a quick pressure check. Should be less than $50.
Pro
Joined: May 2002
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From: Lengede
I’ve been having problems with my 1992 LT1 ever since I swapped to a 396 ci, Meziere water pump and all the other goodies, see signature.
Mine just gets too hot when I drive faster than 80 mph; up to this speed it stays below 210°. I converted to a HD Meziere pump, HD radiator and tried out three different thermostats from 160° to 180° but nothing helped. The only thing that does help is, when I take out the thermostat!!! The engine runs cooler by about 20°. Some people say it’s the Meziere pump which isn’t flowing enough water but at a speed of 80 mph and just touching the throttle, an engine shouldn’t get that hot.
Any ideas??
Mine just gets too hot when I drive faster than 80 mph; up to this speed it stays below 210°. I converted to a HD Meziere pump, HD radiator and tried out three different thermostats from 160° to 180° but nothing helped. The only thing that does help is, when I take out the thermostat!!! The engine runs cooler by about 20°. Some people say it’s the Meziere pump which isn’t flowing enough water but at a speed of 80 mph and just touching the throttle, an engine shouldn’t get that hot.
Any ideas??
Le Mans Master
Joined: Mar 2004
Posts: 8,700
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From: Ft. Lauderdale Fl
Always go with the cheapest and easyiest first. Change the upper and lower radiator hoses and do a complete flush and replace with 50/50 distilled/coolant. Thats where I would start.
Safety Car
Joined: Feb 2002
Posts: 4,212
Likes: 10
From: Sun City West Az
Originally Posted by elefkow
Always go with the cheapest and easyiest first. Change the upper and lower radiator hoses and do a complete flush and replace with 50/50 distilled/coolant. Thats where I would start.
Along with the above suggestion to swap the fan relays to see if the secondary relay is bad. Also, be sure you get the system burped correctly. There are 2 bleed screws on the 92.
Pro
Joined: May 2002
Posts: 678
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From: Lengede
Everything worked fine before I swapped engines!!!!! Okay I have about 100 hp more but for running 80 mph you only need about 40 hp at the most.
Why should I change the hoses?????
What do the fans have to do when driving on the highway?? The fans are for city driving!
Why should I change the hoses?????
What do the fans have to do when driving on the highway?? The fans are for city driving!
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From: Canton GA
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St. Jude Donor '03-'05-'06-'10-'11-'12
See my responses and questions below:
In the '92 and up LT1's, the fans are completely controlled by the ECM. If you short the ALDL pins to go into diagnostic mode, it will turn both fans on without starting the car. Try it. If only one fan turns on, follow the troubleshooting section in the service manual.
I strongly suspect your radiator is clogged. Not internally, but the fins are stuffed with crap. The only way to verify that (and clean it) is to remove the top radiator shroud. How many miles on the car?
Originally Posted by CaptainCaveMan
Ok, i got a 92 LT1 vette and i'm having a little problem with the overheating thing.
If it's parked and running it will just get hotter and hotter How hot is that? Does the needle go into the red?
If i'm going down the highway with the A/C off it will go down to normal range Normal being what temp?
If i'm going down the highway with the A/C on, it will get hotter and hotter until the coolant starts to boil How do you know it's boiling and what does the temp guage and digital display say?
Things i've checked....
1. The radiator is a little dirty, i am going to clean it real good this weekend. How did you determine how dirty? Did you remove the fan shroud?
2. Drivers side fan will turn on, but the passenger side one won't. (bad motor or what?) Do they both turn on when the car is stopped and the A/C on?
3. It has coolant. Burp it. The LT1 coolant system has many places that can have air pockets. Do a search on bleeding air here, there are a few threads about it.
Anything else i should be checking?
If it's parked and running it will just get hotter and hotter How hot is that? Does the needle go into the red?
If i'm going down the highway with the A/C off it will go down to normal range Normal being what temp?
If i'm going down the highway with the A/C on, it will get hotter and hotter until the coolant starts to boil How do you know it's boiling and what does the temp guage and digital display say?
Things i've checked....
1. The radiator is a little dirty, i am going to clean it real good this weekend. How did you determine how dirty? Did you remove the fan shroud?
2. Drivers side fan will turn on, but the passenger side one won't. (bad motor or what?) Do they both turn on when the car is stopped and the A/C on?
3. It has coolant. Burp it. The LT1 coolant system has many places that can have air pockets. Do a search on bleeding air here, there are a few threads about it.
Anything else i should be checking?
I strongly suspect your radiator is clogged. Not internally, but the fins are stuffed with crap. The only way to verify that (and clean it) is to remove the top radiator shroud. How many miles on the car?
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From: Canton GA
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Originally Posted by vettef6
I’ve been having problems with my 1992 LT1 ever since I swapped to a 396 ci, Meziere water pump and all the other goodies, see signature.
Mine just gets too hot when I drive faster than 80 mph; up to this speed it stays below 210°. I converted to a HD Meziere pump, HD radiator and tried out three different thermostats from 160° to 180° but nothing helped. The only thing that does help is, when I take out the thermostat!!! The engine runs cooler by about 20°. Some people say it’s the Meziere pump which isn’t flowing enough water but at a speed of 80 mph and just touching the throttle, an engine shouldn’t get that hot.
Any ideas??
Mine just gets too hot when I drive faster than 80 mph; up to this speed it stays below 210°. I converted to a HD Meziere pump, HD radiator and tried out three different thermostats from 160° to 180° but nothing helped. The only thing that does help is, when I take out the thermostat!!! The engine runs cooler by about 20°. Some people say it’s the Meziere pump which isn’t flowing enough water but at a speed of 80 mph and just touching the throttle, an engine shouldn’t get that hot.
Any ideas??
It is possible the Meziere isn't flowing enough. It may have a weak motor, the impeller may be askew, it may be cavitating, etc. Hell, it may even be wired backwards
Pro
Joined: May 2002
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From: Lengede
As far as I know there has never been a spring in the lower hose, at least there isn’t one in there now.
As a 350ci with about 400 hp I could run day and night full load without getting over 195°. Now after changing engines and trani I’ve been having trouble from the start. At first I had a standard Meziere pump, then I bought a new HD Meziere pump and a HD radiator, nothing helped. Nothing has been changed on the air dam, it looks like new. The condenser is also clean, otherwise I would have had problems before with the 350ci engine.
As a 350ci with about 400 hp I could run day and night full load without getting over 195°. Now after changing engines and trani I’ve been having trouble from the start. At first I had a standard Meziere pump, then I bought a new HD Meziere pump and a HD radiator, nothing helped. Nothing has been changed on the air dam, it looks like new. The condenser is also clean, otherwise I would have had problems before with the 350ci engine.
Le Mans Master
Joined: May 2005
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From: Central Maryland
Originally Posted by vettef6
As far as I know there has never been a spring in the lower hose, at least there isn’t one in there now.
As a 350ci with about 400 hp I could run day and night full load without getting over 195°. Now after changing engines and trani I’ve been having trouble from the start. At first I had a standard Meziere pump, then I bought a new HD Meziere pump and a HD radiator, nothing helped. Nothing has been changed on the air dam, it looks like new. The condenser is also clean, otherwise I would have had problems before with the 350ci engine.
As a 350ci with about 400 hp I could run day and night full load without getting over 195°. Now after changing engines and trani I’ve been having trouble from the start. At first I had a standard Meziere pump, then I bought a new HD Meziere pump and a HD radiator, nothing helped. Nothing has been changed on the air dam, it looks like new. The condenser is also clean, otherwise I would have had problems before with the 350ci engine.
Your lower radiator hose should have a spring in it. The spring keeps the hose from collapsing due to the suction of the pump. If yours has no spring (see if you can squeeze the hose shut by hand when there's no pressure on the system), get one in there. Could very well be all that's wrong.
Bleed the system. Even if you've already done this, do it again. Might still be some air trapped in there. My '94 has two air bleed screws. Find out how many your '92 has, and where they are, and see if any air comes out of them.
The fact that running with the thermostat removed drops your ECT by 20* leads me to believe you have a coolant flow issue, and I think it's a very good chance your lower radiator hose is collapsing because of the absent spring.
Be well,
SJW
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From: The Top of Utah
Originally Posted by SJW
Your lower radiator hose should have a spring in it. The spring keeps the hose from collapsing due to the suction of the pump. If yours has no spring (see if you can squeeze the hose shut by hand when there's no pressure on the system), get one in there. Could very well be all that's wrong.
RACE ON!!!
Pro
Joined: May 2002
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From: Lengede
Originally Posted by SJW
Your lower radiator hose should have a spring in it. The spring keeps the hose from collapsing due to the suction of the pump. If yours has no spring (see if you can squeeze the hose shut by hand when there's no pressure on the system), get one in there. Could very well be all that's wrong.
The fact that running with the thermostat removed drops your ECT by 20* leads me to believe you have a coolant flow issue, and I think it's a very good chance your lower radiator hose is collapsing because of the absent spring.
Be well,
SJW
The fact that running with the thermostat removed drops your ECT by 20* leads me to believe you have a coolant flow issue, and I think it's a very good chance your lower radiator hose is collapsing because of the absent spring.
Be well,
SJW
Since I’m running an electric water pump the flow is always constant, right?? This means with the thermostat open and the engine running the hose should collapse without the car moving, right??
Well, the hose doesn’t collapse with or without the thermostat mounted.
I will though, check out the repair manual what is with this missing spring.
Arnold
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From: Canton GA
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St. Jude Donor '03-'05-'06-'10-'11-'12
Correct, if you're running an electric pump, the water will flow at all times. This may help you in your troubleshooting in that you can turn the pump on and check for flow through the hoses and radiator.
Here's a fantastic read: http://www.theherd.com/articles/lt1_cool.html
Here's a fantastic read: http://www.theherd.com/articles/lt1_cool.html
Pro
Joined: May 2002
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From: Lengede
Thanks for the replies and the links guys.
I looked again at the lower hose and it definitely doesn’t have a spring in it, and it doesn’t collapse!!
The manual doesn’t say anything about a spring either.
Don’t know what else to do at the moment except to drive the way it is, without a thermostat.
Arnold
I looked again at the lower hose and it definitely doesn’t have a spring in it, and it doesn’t collapse!!
The manual doesn’t say anything about a spring either.
Don’t know what else to do at the moment except to drive the way it is, without a thermostat.
Arnold
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Joined: Mar 2005
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From: Nashville TN
If it's parked and running it will just get hotter and hotter How hot is that? Does the needle go into the red? It kept rising to 226 in the mcdonalds parking lot before i hit the highway.
If i'm going down the highway with the A/C off it will go down to normal range Normal being what temp? 200, I guess that's normal for this car
If i'm going down the highway with the A/C on, it will get hotter and hotter until the coolant starts to boil How do you know it's boiling and what does the temp guage and digital display say? The guage was down to the hashmarks, stupid me forgot to look at the digital display. I can hear it boiling and something clicking (seems to be coming not from the overflow tank but from the spot you fill the colant from on the passengerside.
Things i've checked....
1. The radiator is a little dirty, i am going to clean it real good this weekend. How did you determine how dirty? Did you remove the fan shroud? The passenger side of my shroud has a cut in it that you can see the front of the radiator if you look at it with a flashlight.
2. Drivers side fan will turn on, but the passenger side one won't. (bad motor or what?) Do they both turn on when the car is stopped and the A/C on? Nope
3. It has coolant. Burp it. The LT1 coolant system has many places that can have air pockets. Do a search on bleeding air here, there are a few threads about it. I'll have to do that when i do my coolant flush tomorrow
I am going to go through it all this weekend and try to figure it all out.
If i'm going down the highway with the A/C off it will go down to normal range Normal being what temp? 200, I guess that's normal for this car
If i'm going down the highway with the A/C on, it will get hotter and hotter until the coolant starts to boil How do you know it's boiling and what does the temp guage and digital display say? The guage was down to the hashmarks, stupid me forgot to look at the digital display. I can hear it boiling and something clicking (seems to be coming not from the overflow tank but from the spot you fill the colant from on the passengerside.
Things i've checked....
1. The radiator is a little dirty, i am going to clean it real good this weekend. How did you determine how dirty? Did you remove the fan shroud? The passenger side of my shroud has a cut in it that you can see the front of the radiator if you look at it with a flashlight.
2. Drivers side fan will turn on, but the passenger side one won't. (bad motor or what?) Do they both turn on when the car is stopped and the A/C on? Nope
3. It has coolant. Burp it. The LT1 coolant system has many places that can have air pockets. Do a search on bleeding air here, there are a few threads about it. I'll have to do that when i do my coolant flush tomorrow
I am going to go through it all this weekend and try to figure it all out.
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From: Canton GA
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Ok, there's no doubt you have a fan problem. The A/C should turn both of them on. Time to start troubleshooting that.
I really can't emphasize this enough: You MUST remove the fan shroud to be able to see between the condensor and radiator. Looking in that little slit won't allow you to see through the radiator fins where all of the crud is built up. It takes air flow through the radiator to cool it. When the crap builds up between the fins, the air flow drops drastically.
Check your pressure tank cap too, if it's not sealing properly, it won't keep pressure and the fluid will boil sooner.
I really can't emphasize this enough: You MUST remove the fan shroud to be able to see between the condensor and radiator. Looking in that little slit won't allow you to see through the radiator fins where all of the crud is built up. It takes air flow through the radiator to cool it. When the crap builds up between the fins, the air flow drops drastically.
Check your pressure tank cap too, if it's not sealing properly, it won't keep pressure and the fluid will boil sooner.
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Joined: Mar 2005
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From: Nashville TN
Originally Posted by ShawnZR-1
Ok, there's no doubt you have a fan problem. The A/C should turn both of them on. Time to start troubleshooting that.
I really can't emphasize this enough: You MUST remove the fan shroud to be able to see between the condensor and radiator. Looking in that little slit won't allow you to see through the radiator fins where all of the crud is built up. It takes air flow through the radiator to cool it. When the crap builds up between the fins, the air flow drops drastically.
Check your pressure tank cap too, if it's not sealing properly, it won't keep pressure and the fluid will boil sooner.
I really can't emphasize this enough: You MUST remove the fan shroud to be able to see between the condensor and radiator. Looking in that little slit won't allow you to see through the radiator fins where all of the crud is built up. It takes air flow through the radiator to cool it. When the crap builds up between the fins, the air flow drops drastically.
Check your pressure tank cap too, if it's not sealing properly, it won't keep pressure and the fluid will boil sooner.
I'm going to go outside right now and start ripping parts off. If i remember i'll take some pics and post up whatever the hell it is.