Whats normal coolant temp
Thread Starter
Instructor
Joined: May 2010
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Whats normal coolant temp
for a 1996 c4LT1? I replaced plugs, wires, opti, water pump, bleed the heck out of the system like 10 times no more air. And now running between 205 and 212. Don't know why and at what temp is thing running hot? 230/240? After all that work don't want to mess anything else up.
PASTAMIKE..
PASTAMIKE..
Team Owner
Joined: Jul 2006
Posts: 22,190
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From: Kannapolis NC
for a 1996 c4LT1? I replaced plugs, wires, opti, water pump, bleed the heck out of the system like 10 times no more air. And now running between 205 and 212. Don't know why and at what temp is thing running hot? 230/240? After all that work don't want to mess anything else up.
PASTAMIKE..
PASTAMIKE..
Instructor
Joined: May 2013
Posts: 248
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From: Central Minnesota
C4s run really warm. It actually scared me how warm my engine got until I read that it was normal for the cooling fan to kick on at 225 degrees. You can get a different thermostat to get it to run cooler, I wouldn't go any lower than 180 degrees on a fuel injected engine. However the only way to get the cooling fan to kick on lower than 225 is to get a new thermo switch kit. Summit Racing sells them, in fact I have one sitting in my garage that kicks the fan on at 180. I can get you the part number if you wish.
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Instructor
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before I did the work on the car I always ran at 196-200, with the new pump wondering why its hotter, but just remembered I didn't change the thermostat, that could be it but if its ok where its running will get new stat tomorrow.
thanks guys..
pastamike
thanks guys..
pastamike
Le Mans Master
Joined: Dec 2006
Posts: 5,139
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From: H-Town Texas
I've got a 180* T-stat. Runs around 186-189 at highway speeds, around 200+/- stop and go. But it will get up to 230 at stop lights, then fans bring it down.
Instructor
Joined: May 2013
Posts: 248
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From: Central Minnesota
My experience with C4s is L98 and my "old school" engine build, so forgive me if this option is not possible or is already there from factory. You could run an engine oil cooler. That wont decrease the operating temp a whole lot, but will greatly decrease wear and increase the life of your engine oil. Especially if you hit the track with your 'vette at all.
Melting Slicks
Joined: Jul 2005
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As far as I know - all the LT1/LT4 cars have the electric fans controlled by the PCM. On my C4 - the fans come on full at about 230 degrees, and turn back off at around 220. The only ways to get the electric fans to come on earlier is to: 1) Wire a switch into the relay control, and ground the relay's when you want the cooling fans to come on, or 2) reprogram the PCM to turn the fans on at a lower temp. No cooling temp switch will work on these cars...
The LT1/LT4 cars typically run in the 190's on a straight highway cruise, but get down to low speeds, and the temps can easily get to the 230 range.
If you find you're higher than 190's on the highway - look at the air inlet and see if there is crap up in there - C4's tend to collect a lot of crud over the years, and the only way to get it out is to pull the airbox and clean it out by hand....
The LT1/LT4 cars typically run in the 190's on a straight highway cruise, but get down to low speeds, and the temps can easily get to the 230 range.
If you find you're higher than 190's on the highway - look at the air inlet and see if there is crap up in there - C4's tend to collect a lot of crud over the years, and the only way to get it out is to pull the airbox and clean it out by hand....
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Safety Car
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From: SANTA CRUZ CA
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Instructor
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This is one great write up on the lt1 cooling system thanks...
pastamike..
Team Owner
Joined: Dec 1999
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From: Lacey WA RVN 68-69
NCM Sinkhole Donor
Did you check for debris in front of the A/C condenser and the radiator? That's a common cause of higher coolant temps. Is the air dam in place and in good shape?
You should be able to look between the radiator and condenser through the passenger side shroud. Loosen the shroud by removing some of the attaching screws and you can get a vacuum hose down in there. Then spray something like Simple Green or Purple Power on the fins of the radiator and condenser and let it sit for a minute or two. Then use a garden hose to clean all the gunk out.
You should be able to look between the radiator and condenser through the passenger side shroud. Loosen the shroud by removing some of the attaching screws and you can get a vacuum hose down in there. Then spray something like Simple Green or Purple Power on the fins of the radiator and condenser and let it sit for a minute or two. Then use a garden hose to clean all the gunk out.
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Instructor
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Did you check for debris in front of the A/C condenser and the radiator? That's a common cause of higher coolant temps. Is the air dam in place and in good shape?
You should be able to look between the radiator and condenser through the passenger side shroud. Loosen the shroud by removing some of the attaching screws and you can get a vacuum hose down in there. Then spray something like Simple Green or Purple Power on the fins of the radiator and condenser and let it sit for a minute or two. Then use a garden hose to clean all the gunk out.
You should be able to look between the radiator and condenser through the passenger side shroud. Loosen the shroud by removing some of the attaching screws and you can get a vacuum hose down in there. Then spray something like Simple Green or Purple Power on the fins of the radiator and condenser and let it sit for a minute or two. Then use a garden hose to clean all the gunk out.
guess theres worst things to worry about lol..
Safety Car
Joined: Aug 2002
Posts: 3,842
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From: SANTA CRUZ CA
You wrote in one of your posts that you had not changed the tstat.
If it hasn't been changed, do so, and use the correct LT1 tstat.
If the tstat was not opening completely, you will run higher temps,
and your temps are higher than normal.
When you change the tstat, there is no need to bleed the coolant system. The LT1 engine will bleed itself. Just fill the surge tank completely, idle the engine to operating temp with the surge tank cap off, add coolant as needed when the tstat opens, replace the cap.
I'm aware of all the 'bubble' horror stories, and LT1 bleeding 'expert' techniques, and the bleed screw locations, but I have experienced self-bleeding LT1s for 15
years.
If it hasn't been changed, do so, and use the correct LT1 tstat.
If the tstat was not opening completely, you will run higher temps,
and your temps are higher than normal.
When you change the tstat, there is no need to bleed the coolant system. The LT1 engine will bleed itself. Just fill the surge tank completely, idle the engine to operating temp with the surge tank cap off, add coolant as needed when the tstat opens, replace the cap.
I'm aware of all the 'bubble' horror stories, and LT1 bleeding 'expert' techniques, and the bleed screw locations, but I have experienced self-bleeding LT1s for 15
years.
Last edited by don hall; May 11, 2013 at 01:38 PM.
Safety Car
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From: SANTA CRUZ CA
A tstat has absolutely nothing to do with operating temp, unless it is defective. A tstat is designed to open at a predetermined temp allowing the engine to reach operating temp rapidly, and then allowing coolant to circulate to maintain that operating temp.
A 160 vs a 180 tstat only means that the 160 will open sooner, not
reducing the operating temp by 20 deg.
If cooler engine temps are desired, program the cooling fans to operate sooner.
A 160 vs a 180 tstat only means that the 160 will open sooner, not
reducing the operating temp by 20 deg.
If cooler engine temps are desired, program the cooling fans to operate sooner.
Safety Car
Joined: Aug 2002
Posts: 3,842
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From: SANTA CRUZ CA
A 160 tstat opens when the coolant reaches 160. Once it is open, it is no longer in the cooling equation. Opening sooner only means that it will take the engine longer to reach operating temp. A 160 tstat has nothing to do with temps exceeding 160.
As previously posted, owners using 160 tstats have the cooling fans reprogrammed to activate at a lower temp. That is how operating temps can be controlled to a lower level.
Race Director
Joined: Jan 2002
Posts: 12,263
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From: O'Fallon Missouri
^^ There are those of us that do, and those of us that repeat what they read on the internet. I dare you back your claimes up with cash. Name your price, do a poll with C4 LT1 owners that have changed to a 160* stat.
You are right about one thing, reprogramming fans will lower temps at idle and in traffic. But on the highway all is needed in an LT1 is a lower thermostat than stock.
You are right about one thing, reprogramming fans will lower temps at idle and in traffic. But on the highway all is needed in an LT1 is a lower thermostat than stock.
Instructor
Joined: Nov 2011
Posts: 147
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From: Florida
Thermostat determines operating temp at normal light duty operation.
Changing your thermostat will change operating temp if your using the car in light duty operation if your flogging it it will make little difference and you will see your temps hit 200 plus.
g
g
Safety Car
Joined: Aug 2002
Posts: 3,842
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From: SANTA CRUZ CA
STL ...... what is it that you don't understand?
The tstat is only a valve that opens at a predetermined temp. Once it is open, it no longer functions. Once open, it does not increase coolant flow, it does not increase air flow. It is just a configured piece of metal that sits there in the open position. No wires, no connection of any kind.
The secret of the thermostat lies in the small cylinder located on the engine-side of the device. This cylinder is filled with a wax that begins to melt at a predetermined temp. A rod connected to the valve presses into this wax. When the wax melts, it expands significantly and pushes the rod out of the cylinder, opening the valve. Once they are open, the tstats act exactly alike, doing nothing.
If your 'theory' was valid, run your vette without a tstat. It should really run 'cold', probably never reaching operating temp.
Please explain technically just what your 160 tstat does to keep operating temps below 180. Increase air flow? Increase coolant flow?...... those are the two elements that maintain temps.
I really don't care if your vette makes ice cubes with your 160 tstat,
but you should really educate yourself before making facetious challenges.
The tstat is only a valve that opens at a predetermined temp. Once it is open, it no longer functions. Once open, it does not increase coolant flow, it does not increase air flow. It is just a configured piece of metal that sits there in the open position. No wires, no connection of any kind.
The secret of the thermostat lies in the small cylinder located on the engine-side of the device. This cylinder is filled with a wax that begins to melt at a predetermined temp. A rod connected to the valve presses into this wax. When the wax melts, it expands significantly and pushes the rod out of the cylinder, opening the valve. Once they are open, the tstats act exactly alike, doing nothing.
If your 'theory' was valid, run your vette without a tstat. It should really run 'cold', probably never reaching operating temp.
Please explain technically just what your 160 tstat does to keep operating temps below 180. Increase air flow? Increase coolant flow?...... those are the two elements that maintain temps.
I really don't care if your vette makes ice cubes with your 160 tstat,
but you should really educate yourself before making facetious challenges.
Last edited by don hall; May 11, 2013 at 08:58 PM.