Overheating, What is wrong?
TECH Enthusiast
Joined: May 2005
Posts: 669
Likes: 0
From: Charlotte, NC
It does matter. This way you know for next time and I won't assume that your meaning a manual fan switch that you installed 2 months ago was causing your fans not to come on. (hence why I asked you where you got it from). Now you know what to call the components correctly in case it ever comes up again. It's actauly really common for people to comfuse the sending unit in the head for a sensor. Now you can help to set them streight as well.
What happend to your temp sensor is it lost it's calibration. Not enough to trigger any other problems but shifted the resistence higher so it was reading a lower temp. For example, you might have been running 240* but the computer was only seeing 220*. This means that teh fans will still not come on even tho your about to overheat. It's fairly common on GM's (especialy saturns).
Glad you got it to work correctly.
What happend to your temp sensor is it lost it's calibration. Not enough to trigger any other problems but shifted the resistence higher so it was reading a lower temp. For example, you might have been running 240* but the computer was only seeing 220*. This means that teh fans will still not come on even tho your about to overheat. It's fairly common on GM's (especialy saturns).
Glad you got it to work correctly.
TECH Enthusiast
Joined: Sep 2004
Posts: 595
Likes: 0
From: Clarksville,Tn
May I add something to the argument?? I don't think yer 100% correct in saying the sending unit is just for the guage. I broke my sending unit last year during a header install. Drove it to town the next day to get the duals put on and it was missing and backfiring terribly after it warmed up. Did this all the way back home after it warmed up again. When I got back home I changed out the sending unit and it has never missed again. I think it's for more than just the guage but what I don't know.
TECH Enthusiast
Joined: May 2005
Posts: 669
Likes: 0
From: Charlotte, NC
Sorry, but the sending unit in the head has everything to do with the gauge and nothing to do with engine performance. It doesn't even feed at all to the PCM. It runs directly to the cluster.
Also, I am not arguing. I am informing to clear things up. if this makes some people mad so be it. I would rather have the correct info out there and be yelled at then have incorrect information being passed along.
Also, I am not arguing. I am informing to clear things up. if this makes some people mad so be it. I would rather have the correct info out there and be yelled at then have incorrect information being passed along.
TECH Enthusiast
Joined: Sep 2004
Posts: 595
Likes: 0
From: Clarksville,Tn
Not arguing here either. I'm here to give help on what I can and learn what I don't know. I know how my car was acting before and after the sending unit change and I changed nothing else on it. I'll check out a wiring diagram in the haynes manual tonight when I get home, not to prove you right or wrong, just so I'll know for myself for future references.
By the way, you do seem knowledgable on these cars, I have a post on here that nobody seems to know the answer to. If you can answer it then I'd be much obliged. Here it is https://ls1tech.com/forums/lt1-lt4-modifications/369091-lt1-valvetrain.html
By the way, you do seem knowledgable on these cars, I have a post on here that nobody seems to know the answer to. If you can answer it then I'd be much obliged. Here it is https://ls1tech.com/forums/lt1-lt4-modifications/369091-lt1-valvetrain.html
Teching In
Joined: Jun 2005
Posts: 19
Likes: 0
From: Kansas City, MO
my thing is on here that he is asking for help & you all treat people like they are dumbasses. you don't have to sound like a dick about it. he told you that the PARTS place which was AUTOZONE said that this is what they called it. so if you want to correct someone or a place of business, then you need to call them & tell them that they are listing things wrong. its working & that is it. if you want people to listen to you then you need to take a different way of saying it. just because you are the only one saying this doesn't mean what it is, doesn't mean ****, unless you have writing or something to back it up from the manufacture. i would like to see what you say besides your word.
TECH Enthusiast
Joined: May 2005
Posts: 669
Likes: 0
From: Charlotte, NC
Show me once where I was sounding "like a dicK"? People will take it how they wish to take it. But if your going to listen to what some pimple covered idiot at autozone tells you then I highly recomend that you never work on your car.
All you have to do is think about it. They have been caling them coolant temp sensors for years. A switch requires a set of contacts that will move. A sensor has no such construction. how can a switch be a sensor? it's can't. Even IF the sensor in the water pump was ONLY there for fan control it would still not be called a switch. Autozone is filled with morons that don't know a ECT from an ICM. Just because they call it something wrong doesn't mean that it's right for you to assume that they are.
All you have to do is think about it. They have been caling them coolant temp sensors for years. A switch requires a set of contacts that will move. A sensor has no such construction. how can a switch be a sensor? it's can't. Even IF the sensor in the water pump was ONLY there for fan control it would still not be called a switch. Autozone is filled with morons that don't know a ECT from an ICM. Just because they call it something wrong doesn't mean that it's right for you to assume that they are.
LS1 Tech Stories
The Best V8 Stories One Small Block at Time
6 Common C5 Corvette Failures and What's Involved In Repairing Them
Pouria Savadkouei
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph
Verdad Gallardo
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked
Pouria Savadkouei
Top 10 Most Powerful Chevy Trucks Ever Made!
Hennessey's New Supercharged Silverado ZR2 Has 700 HP
Verdad Gallardo
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes
Verdad Gallardo
Awesome K5 Blazer Restomod Comes With C7 Corvette Power
Verdad Gallardo
10 Camaros You Should Never Buy
10 LS Engine Myths That Refuse to Die
Verdad Gallardo
Thread Starter
TECH Apprentice
iTrader: (15)
Joined: Nov 2003
Posts: 399
Likes: 0
From: Junction City, Kansas
I didn't confuse the temp switch with the coolant sensor. I had the right one but called it the wrong thing from Autozone. The name is corrected. The temperature sensor does feed to the pcm, how else is the computer going to get its temperature when the coolant sensor in the water pump was bad? I have ordered the dealer manuals for this year car and will check out the wiring diagram and proper names to ensure we are all correct.
TECH Enthusiast
Joined: Sep 2004
Posts: 595
Likes: 0
From: Clarksville,Tn
Checked the Haynes manual and it doesn't show the sending unit, just the sensor on the water pump so I did a lil test yesterday. I unplugged the sending unit on the head and drove it to work and back home like that. To clear up my side of the discussion, I will concede that the sending unit is only for the guage. Sure would like to know why it made my car run like **** when I broke it the first time.
Thread Starter
TECH Apprentice
iTrader: (15)
Joined: Nov 2003
Posts: 399
Likes: 0
From: Junction City, Kansas
HR, riddle me this then. The PCM knew the temperature because of the temperature sending unit. I verified that with a scanner that gave me all the info that the PCM was reading. The fans didn't come on with sending unit plugged in, but unplugged they did regardless of the temperature. If the sending unit didn't tell the pcm anything, then why did the fans default to on?
TECH Enthusiast
Joined: Sep 2004
Posts: 595
Likes: 0
From: Clarksville,Tn
Are you confusing the sending unit in the head with the coolant temp sensor in the water pump?? Which did you unplug?? If yer talkin about the sensor in the water pump I can see why it would default to fans on if it was unplugged. That would keep you from overheating the motor since the ecm cant tell wha the temp is and when to turn them on.
TECH Enthusiast
Joined: May 2005
Posts: 669
Likes: 0
From: Charlotte, NC
^ exactly. just to clear this up.
The Coolant temp SENSOR is in the water pump. It's a 2 wire connector, one side ground the other a 5 volt reffernece. the signal is fed to the computer. As temp goes up resistence goes down which in turn means that the voltage will increese. This is used for fan operation, minor timing adjustments, cold start ect ect.
The coonat temp SENDING UNIT is the single wire connector and mounted in the head between the 1 and 3 ports. It gets a ground from the head and is a simple thermister. As temp goes up resistence goes down which means more ground gets to the gauge, the more ground the hotter it reads.
When you unplug the coolant temp sensor it will (usualy) trip the fans on based on failsafe and set a code.
The Coolant temp SENSOR is in the water pump. It's a 2 wire connector, one side ground the other a 5 volt reffernece. the signal is fed to the computer. As temp goes up resistence goes down which in turn means that the voltage will increese. This is used for fan operation, minor timing adjustments, cold start ect ect.
The coonat temp SENDING UNIT is the single wire connector and mounted in the head between the 1 and 3 ports. It gets a ground from the head and is a simple thermister. As temp goes up resistence goes down which means more ground gets to the gauge, the more ground the hotter it reads.
When you unplug the coolant temp sensor it will (usualy) trip the fans on based on failsafe and set a code.
