What temp?
Thread Starter
Intermediate
Joined: Dec 2006
Posts: 25
Likes: 0
What temp?
My 92 vette is running at about 225 F to 230 F when in idle. Of course when driving it runs about 217 F to 220 F. With the air conditioning on the other fan comes on and drops it a few degrees. Does this temperature sound about where it should be or is it to high and do I need to replace the thermostat?
Also I replace my opti spark module which was really fun by the way
and I replace the plugs and wires and it seems to run a little rough when in idle and cut off in idle occasionally. Before I replaced the opti spark I got codes of 42 and 43. 42 was the opti spark and 43 was the knock sensor. Could the knock sensor be my issue for the rough idle or the reason its cutting off? Where are the 2 knock sensors on my car?
Also I replace my opti spark module which was really fun by the way
and I replace the plugs and wires and it seems to run a little rough when in idle and cut off in idle occasionally. Before I replaced the opti spark I got codes of 42 and 43. 42 was the opti spark and 43 was the knock sensor. Could the knock sensor be my issue for the rough idle or the reason its cutting off? Where are the 2 knock sensors on my car?
Race Director
Joined: Feb 2003
Posts: 11,671
Likes: 20
From: Lake Wylie SC
I,too, have a 92 and your temps are just about normal. Why so high? GM needed to get the emmissions cleaned up a little and putting the operating temps up helped. Remember, this is the first year of the LT1 and they also went to synthetic oil to with-stand the higher temps. Replacing your T-stat will not bring your temps down as you probably have a 190 in there already. Your T-stat only allows you to warm the engine up quickly and is full open at 190 (if that's what's in there). Make sure the area between your A/C condenser and the radiator is clear of junk. I run a 180 t-stat and my operating temp is around 190 to 200. I also run an electric coolant pump which moves more coolant at idle which increases cooling. Putting the A/C on turns on your cooling fans and usually drops the temp a little. How old is your coolant? When you do change it, stay with the coolant type you have in it (usually the green stuff) and 50-50 mix is good. 
Melting Slicks
Joined: Oct 2004
Posts: 2,662
Likes: 8
From: Knoxville Tennessee
Strick is correct on the emmissions.. I installed a DeWitt radiator and a 160 t-stat and my car never gets over 200 degrees; which is where I prefer it. The LT-1 is a great engine and is designed to run at higher temps but those temps will slowly destroy other components under the hood that will not tolerate them as well.
Bernie
Bernie
Burning Brakes
Joined: Aug 2006
Posts: 1,189
Likes: 0
From: Houston PA
When I see the temps starting to creep up, I turn the a/c on so the fan will run, this keeps the temp on my 94 at about 205. 2 knock sensors, on the bottom side of the block, one on each side. Pull them, and open the rad pitcock when changing to coolant(and opti) to drain all the coolant.
Burning Brakes
Joined: Dec 2000
Posts: 1,161
Likes: 0
From: Orangeburg, NY
Your temperatures are normal as the car traditionally runs hot. the fan does not engage until 226-228 degrees. When the a/c is engaged the fan automatically goes on. I lowered the operating temperatures by doing several things:
Flush the system and change the coolant - 50/50 mix
changed the thermostat to a 180. (also drilled two small holes in the thermostat ring to allow for the escape of air).
Cleaned the air intake for the radiator. You will be suprised at what you would find.
Replace the radiator cap.
If you are energetic, you can easily pull the radiator, and clean it along with the surrounding area (clean the a/c coils as well). I used simple green as a cleaner and it worked great.
Over time road dirt and grime build up on the radiator which reduces heat dissipation.
Flush the system and change the coolant - 50/50 mix
changed the thermostat to a 180. (also drilled two small holes in the thermostat ring to allow for the escape of air).
Cleaned the air intake for the radiator. You will be suprised at what you would find.
Replace the radiator cap.
If you are energetic, you can easily pull the radiator, and clean it along with the surrounding area (clean the a/c coils as well). I used simple green as a cleaner and it worked great.
Over time road dirt and grime build up on the radiator which reduces heat dissipation.
Thread Starter
Intermediate
Joined: Dec 2006
Posts: 25
Likes: 0
I have changed my radiator out brand new ac delco. Cleaned the radiator shroud of all debris. Of course flushed the system. 50-50 mix added. I don't know what t-stat I have? I would like it to run at or below 200.
Are the knock sensors on my 92 vette easy access points.....I mean so far nothing has been easy except changing the alternator.
Or do I have to take apart the entire engine to get to the knock sensors as well?
Are the knock sensors on my 92 vette easy access points.....I mean so far nothing has been easy except changing the alternator.
Or do I have to take apart the entire engine to get to the knock sensors as well?
Burning Brakes
Joined: Dec 2000
Posts: 1,161
Likes: 0
From: Orangeburg, NY
The knock sensors are not hard to get to.
Before you do that, change the thermostat, but first you might just be low on coolant. After changing out the radiator, did you burp the system. Sometimes it takes several tries to get all of the air out of the system.
If you change the thermostat, drill two small holes (approx 3/16" in the thermostat base rim. This will help with the burping the system and getting all of the air out. MAKE sure you put the thermostat in the correct way. I don't know how many times I have seen them put in backwards.
Before you do that, change the thermostat, but first you might just be low on coolant. After changing out the radiator, did you burp the system. Sometimes it takes several tries to get all of the air out of the system.
If you change the thermostat, drill two small holes (approx 3/16" in the thermostat base rim. This will help with the burping the system and getting all of the air out. MAKE sure you put the thermostat in the correct way. I don't know how many times I have seen them put in backwards.
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Safety Car
Joined: Jul 2004
Posts: 3,834
Likes: 30
.......i flushed my cooling system out a few weeks ago and did a 50-50 mix and added water wetter to it and my temps went UP!.....it was cooler with more water then antifreeze. after doing some research, i determined that if i had more water (distilled) it would run COOLER as the water will conduct the heat better.........i will eventually wind up draining some off and throwing some more water ion there w/o compromising the corrosion additives or boiling points to critical levels...
Pro
Joined: Nov 2005
Posts: 536
Likes: 0
From: Bardstown Kentucky
My car ran hot in trafic yesterday with the AC on, around 224*. I have a 160* thermostat, an electric water pump, and my fans are set to come on at 180*. My outside temp was showing 102*. I checked to make sure the fans were on and they were running full blast. The car would start to cool when I turned off the AC. It seems like the car didnt start doing this until it got up to 100* or better outside.
Le Mans Master
Joined: Aug 2004
Posts: 5,141
Likes: 7
From: Metairie Louisiana
With outside temps of 97-99 last weekend in traffic with the AC full blast I hit 212 deg. That was the highest I have seen since the Dewitt install.
Last edited by rickneworleansla; Aug 16, 2007 at 10:45 AM.
Pro
Joined: Nov 2005
Posts: 536
Likes: 0
From: Bardstown Kentucky
That is because your fans are already programmed to turn on earlier. I believe turning on the AC in that case does nothing but introduce more heat to the radiator which sits behind the condenser. With a stock program turning on the AC kicks on the second fan which lowers the temps. Ours, with the modified tune, is already running by 180 deg. For a while I thought something was wrong with mine because it would get hotter when I turned on the AC above 180 deg. People would tell me it should drop temp but they had stock programming. I'm not 100% sure this is correct but it makes sense to me.
With outside temps of 97-99 last weekend in traffic with the AC full blast I hit 212 deg. That was the highest I have seen since the Dewitt install.
With outside temps of 97-99 last weekend in traffic with the AC full blast I hit 212 deg. That was the highest I have seen since the Dewitt install.
I see what you are saying, since both my fans come on at the same time without AC its going to get hotter when I turn on the AC, because I am adding the condenser heat to the radiator. Man that sucks, I was really hoping to keep the temps down on this thing. Running both fans, E pump, 160* thermo. Do you think the Dewitt is worth it?
I read that it is hard to keep the temp down on these cars at idle no matter what you do.
Le Mans Master
Joined: Aug 2004
Posts: 5,141
Likes: 7
From: Metairie Louisiana
I see what you are saying, since both my fans come on at the same time without AC its going to get hotter when I turn on the AC, because I am adding the condenser heat to the radiator. Man that sucks, I was really hoping to keep the temps down on this thing. Running both fans, E pump, 160* thermo. Do you think the Dewitt is worth it?
I read that it is hard to keep the temp down on these cars at idle no matter what you do.
I read that it is hard to keep the temp down on these cars at idle no matter what you do.
Safety Car
Joined: Aug 2006
Posts: 4,147
Likes: 452
From: Port St. Lucie West Florida
I see what you are saying, since both my fans come on at the same time without AC its going to get hotter when I turn on the AC, because I am adding the condenser heat to the radiator. Man that sucks, I was really hoping to keep the temps down on this thing. Running both fans, E pump, 160* thermo. Do you think the Dewitt is worth it?
I read that it is hard to keep the temp down on these cars at idle no matter what you do.
I read that it is hard to keep the temp down on these cars at idle no matter what you do.
Advanced
Joined: Oct 2006
Posts: 84
Likes: 0
My LT4 runs very hot at idle - even in 80 deg F weather. It is fine when running, but at idle it goes to 240 deg or just about at the HOT range on the analog gauge (265 deg). The AC will activate both fans and things get better, even at idle. But I do not think the primary fan activates at all. What could be the problem and how to fix if the fan does not engage at all?
Advanced
Joined: Oct 2006
Posts: 84
Likes: 0
Your temperatures are normal as the car traditionally runs hot. the fan does not engage until 226-228 degrees. When the a/c is engaged the fan automatically goes on. I lowered the operating temperatures by doing several things:
Flush the system and change the coolant - 50/50 mix
changed the thermostat to a 180. (also drilled two small holes in the thermostat ring to allow for the escape of air).
Cleaned the air intake for the radiator. You will be suprised at what you would find.
Replace the radiator cap.
If you are energetic, you can easily pull the radiator, and clean it along with the surrounding area (clean the a/c coils as well). I used simple green as a cleaner and it worked great.
Over time road dirt and grime build up on the radiator which reduces heat dissipation.
Flush the system and change the coolant - 50/50 mix
changed the thermostat to a 180. (also drilled two small holes in the thermostat ring to allow for the escape of air).
Cleaned the air intake for the radiator. You will be suprised at what you would find.
Replace the radiator cap.
If you are energetic, you can easily pull the radiator, and clean it along with the surrounding area (clean the a/c coils as well). I used simple green as a cleaner and it worked great.
Over time road dirt and grime build up on the radiator which reduces heat dissipation.
I need to know how HOT this stock setup can/should run, what is "normal" for these engines at idle and how to test the fan circuit? Never had any boil over, but am concerned about engine damage. When the car is moving it goes into the middle temp range of the coolant gauge, in the 200's. Oil never hot. My A/C does activate both fans, not just one, because primary fan does not seem to activate at all as far as I can tell.
Burning Brakes
Joined: Jan 2007
Posts: 1,117
Likes: 1
From: Central NJ
Mine LT4 runs very hot at idle, pushing very close to the HOT hash marks on the analog guage which are nearly 240-250 deg F. I just changed the coolant and it makes only a little difference.
I need to know how HOT this stock setup can/should run, what is "normal" for these engines at idle and how to test the fan circuit? Never had any boil over, but am concerned about engine damage. When the car is moving it goes into the middle temp range of the coolant gauge, in the 200's. Oil never hot. My A/C does activate both fans, not just one, because primary fan does not seem to activate at all as far as I can tell.
I need to know how HOT this stock setup can/should run, what is "normal" for these engines at idle and how to test the fan circuit? Never had any boil over, but am concerned about engine damage. When the car is moving it goes into the middle temp range of the coolant gauge, in the 200's. Oil never hot. My A/C does activate both fans, not just one, because primary fan does not seem to activate at all as far as I can tell.
My lt4 runs at 187-195 after my water pump and coolant change, before that it would never go below 195 and would go up to 208.
How many miles on your car? What does the digital read out say?