Car overheating, replaced most. Maybe fans or short -1995 z28 Lt1
03-31-2018, 06:43 AM
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Car overheating, replaced most. Maybe fans or short -1995 z28 Lt1 Okay so 1.2k miles ago I had a shop replace my waterpump as well as thermostat, And brand new battery. 1 week ago I went for a 10 minute drive and the car within 4 minutes pegged the temp gauge Passed 260 and lost about 3 gal of antifreeze out of the overflow fill.
I assumed they used the wrong thermostat so I swapped the tstat, refilled and purged both lines untill radiator was full and I can see the antifreeze flowing through the radiator which leads me to beleive that the waterpump is working as well as the radiator and tstat.
Still the car at idle (Too afraid to drive and crack the block) is still pegged on overheat after 4 mim at dead idle, side note battery keeps dying (Which again is brand new). I have also checked the 3 relays for the two fans by replacing them and the one 10amp fuse is not burnt out either, Block seems to be holding the antifreeze now. Only thing I can think of is fans on turning on, I cant get under the car to check and too afraid to slice my fingers.
whats next, Im assuming since the battery keeps dying after a day that there is a short somwhere, (but I wouldnt even know where to begin. (No idea how to find a short) Either that or the temp sensor on the back of the water pump needs to be replaced. Am I on the right path? Or any suggestions?
I assumed they used the wrong thermostat so I swapped the tstat, refilled and purged both lines untill radiator was full and I can see the antifreeze flowing through the radiator which leads me to beleive that the waterpump is working as well as the radiator and tstat.
Still the car at idle (Too afraid to drive and crack the block) is still pegged on overheat after 4 mim at dead idle, side note battery keeps dying (Which again is brand new). I have also checked the 3 relays for the two fans by replacing them and the one 10amp fuse is not burnt out either, Block seems to be holding the antifreeze now. Only thing I can think of is fans on turning on, I cant get under the car to check and too afraid to slice my fingers.
whats next, Im assuming since the battery keeps dying after a day that there is a short somwhere, (but I wouldnt even know where to begin. (No idea how to find a short) Either that or the temp sensor on the back of the water pump needs to be replaced. Am I on the right path? Or any suggestions?
Last edited by Garrett Fleming; 03-31-2018 at 07:21 AM. Reason: More info
03-31-2018, 10:10 AM
#2
I'm not up to speed on LT1 cars, but if your temp sensor is bad the fans won't turn on, or may not turn on at the right time/temp.
But when your engine is cold....and you start it up.....you can watch the temp gauge rise and then you can verify if the fans are coming on AROUND the proper temp, according to the gauge. If you're temp gauge keeps climbing way past normal operating temp and the fans never come on.....change that temp sensor.....
Sometimes sensors also fail or go bad when the coolant level drops so low and the sensor is not still wet with coolant. Mine did that once....it was perfect till I did a coolant drain and replace.......Had to go get a new one.
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But when your engine is cold....and you start it up.....you can watch the temp gauge rise and then you can verify if the fans are coming on AROUND the proper temp, according to the gauge. If you're temp gauge keeps climbing way past normal operating temp and the fans never come on.....change that temp sensor.....
Sometimes sensors also fail or go bad when the coolant level drops so low and the sensor is not still wet with coolant. Mine did that once....it was perfect till I did a coolant drain and replace.......Had to go get a new one.
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03-31-2018, 10:56 AM
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I can definately replace the temp sensor, but again whats causing a brand new battery to die everyday I go out there I have to jump it. (keep in mind I know zero about electrical) could a bad temp sensor also be shorting or not grounded or cause that battery to die?
03-31-2018, 02:28 PM
#4
I can definately replace the temp sensor, but again whats causing a brand new battery to die everyday I go out there I have to jump it. (keep in mind I know zero about electrical) could a bad temp sensor also be shorting or not grounded or cause that battery to die?
Maybe charge it full....disconnect it from the car completely. Just let it sit by itself. See if it still loses its charge overnight. If it does...its a bad (new) battery.
Because a fully charged battery should NOT die in just one night from something drawing a little bit of power from it all night. Unless maybe the fans are kicking on and running for a few hours....
.
03-31-2018, 04:57 PM
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No. But a bad (new) battery sure can drain in one night. If I were you I would take it back there and have it tested for free. Or take it to an auto parts store...testing is usually free. See if its discharging.....
Maybe charge it full....disconnect it from the car completely. Just let it sit by itself. See if it still loses its charge overnight. If it does...its a bad (new) battery.
Because a fully charged battery should NOT die in just one night from something drawing a little bit of power from it all night. Unless maybe the fans are kicking on and running for a few hours....
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Maybe charge it full....disconnect it from the car completely. Just let it sit by itself. See if it still loses its charge overnight. If it does...its a bad (new) battery.
Because a fully charged battery should NOT die in just one night from something drawing a little bit of power from it all night. Unless maybe the fans are kicking on and running for a few hours....
.
Now just gotta figure out my overheating issue. Which im confident has to be the water pump sensor. Without having to drain the coolant from the block how easy would it be to unscrew the sensor and put the new one in fast so I dont need to yet again buy antifreeze and purge repeatedly. I imagine with quick hands maybe an ounce will come out?
Last edited by Garrett Fleming; 03-31-2018 at 05:03 PM.
03-31-2018, 06:05 PM
#6
Figured out the battery issue, its the negative Bolt is stripped, it only goes in Half way any further and it just losens back to off. Thats my short. My issue is theres no way to remove the bolt from the black housing is there? Correct me if im wrong but I need a whole new negative battery cable with new bolt. I tried everything to remove the old bolt hoping I could just buy a new one.
Now just gotta figure out my overheating issue. Which im confident has to be the water pump sensor. Without having to drain the coolant from the block how easy would it be to unscrew the sensor and put the new one in fast so I dont need to yet again buy antifreeze and purge repeatedly. I imagine with quick hands maybe an ounce will come out?
For the overheating issue, I had a 95 Z28 as my very first F-Body and out of nowhere it just started overheating, temp gauge pegged to the red line, fans weren't kicking on and we just could not figure out what was wrong. Turned out to be the water temperature sensor. I believe its installed right in the front of the block on the drivers side.. 15 minute fix and never had that problem again... I'm about 90% sure this is your problem.
04-01-2018, 08:40 AM
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This is very incorrect, I have had to replace them on F-Bodies before. They are available at Wal-Mart, you use pliers and just pull it back while wiggling it out so the threads one at a time wiggle out of the metal housing, then push the replacement back in... you do NOT need a new battery cable... ...but you may need a new battery since its drained so many times, Batteries are typically cooked if they are fully discharged .. they typically never hold a full charge or their life span is massacred.
For the overheating issue, I had a 95 Z28 as my very first F-Body and out of nowhere it just started overheating, temp gauge pegged to the red line, fans weren't kicking on and we just could not figure out what was wrong. Turned out to be the water temperature sensor. I believe its installed right in the front of the block on the drivers side.. 15 minute fix and never had that problem again... I'm about 90% sure this is your problem.
For the overheating issue, I had a 95 Z28 as my very first F-Body and out of nowhere it just started overheating, temp gauge pegged to the red line, fans weren't kicking on and we just could not figure out what was wrong. Turned out to be the water temperature sensor. I believe its installed right in the front of the block on the drivers side.. 15 minute fix and never had that problem again... I'm about 90% sure this is your problem.
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04-01-2018, 09:26 AM
#8
If its your first time, you're going to loose alittle bit of coolant, but not alot, nothing that you won't be able to top off with a jug of premixed antifreeze.
So basically you'll unplug it, unscrew it, coolant is going to leak for about 20 seconds on average if you can have the new sensor ready to go right in...DONT DROP IT... and just rescrew and tighten it back in. Coolant loss will be minimal, but there will be some.
04-01-2018, 09:44 AM
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This is very incorrect, I have had to replace them on F-Bodies before. They are available at Wal-Mart, you use pliers and just pull it back while wiggling it out so the threads one at a time wiggle out of the metal housing, then push the replacement back in... you do NOT need a new battery cable... ...but you may need a new battery since its drained so many times, Batteries are typically cooked if they are fully discharged .. they typically never hold a full charge or their life span is massacred.
For the overheating issue, I had a 95 Z28 as my very first F-Body and out of nowhere it just started overheating, temp gauge pegged to the red line, fans weren't kicking on and we just could not figure out what was wrong. Turned out to be the water temperature sensor. I believe its installed right in the front of the block on the drivers side.. 15 minute fix and never had that problem again... I'm about 90% sure this is your problem.
For the overheating issue, I had a 95 Z28 as my very first F-Body and out of nowhere it just started overheating, temp gauge pegged to the red line, fans weren't kicking on and we just could not figure out what was wrong. Turned out to be the water temperature sensor. I believe its installed right in the front of the block on the drivers side.. 15 minute fix and never had that problem again... I'm about 90% sure this is your problem.
Always remember to take your time when working anything automotive, nothing is worth rushing.
If its your first time, you're going to loose alittle bit of coolant, but not alot, nothing that you won't be able to top off with a jug of premixed antifreeze.
So basically you'll unplug it, unscrew it, coolant is going to leak for about 20 seconds on average if you can have the new sensor ready to go right in...DONT DROP IT... and just rescrew and tighten it back in. Coolant loss will be minimal, but there will be some.
If its your first time, you're going to loose alittle bit of coolant, but not alot, nothing that you won't be able to top off with a jug of premixed antifreeze.
So basically you'll unplug it, unscrew it, coolant is going to leak for about 20 seconds on average if you can have the new sensor ready to go right in...DONT DROP IT... and just rescrew and tighten it back in. Coolant loss will be minimal, but there will be some.
04-01-2018, 06:17 PM
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Last update, I fixed the neg battery cable with a new bolt so thats fixed. However I replaced the water pump temp sensor and car still (at idle) pegs to 260 after 5 minutes. I noticed BOTH fans are on *only when A/C is turned on (still overheats though) I pulled pcm fuse for 30 seconds to reset, no luck there either.
So to recap. Waterpump replaced 1.2k miles ago. Then around 10 days ago overheated and poured antifreeze everywhere. Since then I have replaced the thermostat (correct one) refilled with coolant and purged lines, replaced water pump temp sensor, pulled fan fuse (which is not burnt) and tested all 3 fan relays under fuse box by replacing each with fog lamps (all turn fog lamps on). Fans only come on when A/C on. But still overheats. At this point im ready to flatbed the car and have it taken somewhere. Unless anyone has any other ideas to look for?
So to recap. Waterpump replaced 1.2k miles ago. Then around 10 days ago overheated and poured antifreeze everywhere. Since then I have replaced the thermostat (correct one) refilled with coolant and purged lines, replaced water pump temp sensor, pulled fan fuse (which is not burnt) and tested all 3 fan relays under fuse box by replacing each with fog lamps (all turn fog lamps on). Fans only come on when A/C on. But still overheats. At this point im ready to flatbed the car and have it taken somewhere. Unless anyone has any other ideas to look for?
04-01-2018, 09:39 PM
#11
Last update, I fixed the neg battery cable with a new bolt so thats fixed. However I replaced the water pump temp sensor and car still (at idle) pegs to 260 after 5 minutes. I noticed BOTH fans are on *only when A/C is turned on (still overheats though) I pulled pcm fuse for 30 seconds to reset, no luck there either.
So to recap. Waterpump replaced 1.2k miles ago. Then around 10 days ago overheated and poured antifreeze everywhere. Since then I have replaced the thermostat (correct one) refilled with coolant and purged lines, replaced water pump temp sensor, pulled fan fuse (which is not burnt) and tested all 3 fan relays under fuse box by replacing each with fog lamps (all turn fog lamps on). Fans only come on when A/C on. But still overheats. At this point im ready to flatbed the car and have it taken somewhere. Unless anyone has any other ideas to look for?
So to recap. Waterpump replaced 1.2k miles ago. Then around 10 days ago overheated and poured antifreeze everywhere. Since then I have replaced the thermostat (correct one) refilled with coolant and purged lines, replaced water pump temp sensor, pulled fan fuse (which is not burnt) and tested all 3 fan relays under fuse box by replacing each with fog lamps (all turn fog lamps on). Fans only come on when A/C on. But still overheats. At this point im ready to flatbed the car and have it taken somewhere. Unless anyone has any other ideas to look for?
Defective water pumps aren't uncommon, here's one I got right out the box BRAND NEW:
Not saying thats your problem, just saying don't rule it out.
Thermostats usually fail stuck open which usually leads the car to running to cold instead of overheating.
You say both fans are only coming on when the Air Conditioner is on?
Here is a test for you, try to get the car to a interstate or any road where the speed limit is 55 MPH or greater with no stops for a significant distance...run it at atleast 55 MPH or higher... see if it still tries to overheat with the A/C OFF... if it DOESN'T overheat, there is a problem with the fans and the PCM triggering them... as the speed of 55+ MPH will keep the radiator cool enough where the fans running or not are irrelevant. The temp sensor is what tells the PCM when to turn the fans on, not sure if its possible it could be a wiring issue or if the A/C uses a different circuit to trigger than fans or not... but there's a possibility.
If it DOES overheat, the only other things I can think of is possibly head-gaskets ASSUMING its properly bled that is.
04-02-2018, 12:03 PM
#12
OP
you did bleed the coolant system...right?
LT1 motors require this unlike other SBC
The temp sensor on the head is for the gauge. The one on front of the WP is for the PCM/fans. If you disconnect that sensor with engine running both fans should start. If not you have a wiring issue with the fans or fan motors are burned out
also the T stat is specific to the LT1...you have the correct one??
letting the engine get so hot the temp gauge pegs is a VERY bad idea. You can seriously damage motor and at the very least lose a head gasket
you did bleed the coolant system...right?
LT1 motors require this unlike other SBC
The temp sensor on the head is for the gauge. The one on front of the WP is for the PCM/fans. If you disconnect that sensor with engine running both fans should start. If not you have a wiring issue with the fans or fan motors are burned out
also the T stat is specific to the LT1...you have the correct one??
letting the engine get so hot the temp gauge pegs is a VERY bad idea. You can seriously damage motor and at the very least lose a head gasket
04-02-2018, 01:48 PM
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I did read that on shbox, but im fed up.(and on limited budget) I had the car flatbedded this morning to a shop who is experienced with Fbodies and chevys, z06. Im thinking its a short/ground, as the brand new battery keeps dying. I have a relative who will pay up to 500$ or less for the shop to fix it (inbetween jobs) if its a head gasket im screwed. I got over 10k in this car already. Which means ill have to part the car out as im sure theyll want more than 500$ to replace gasket. But they have the scan tools so hopefully its some dumb short/ground. This was my dream car too. Ah well
04-02-2018, 02:33 PM
#16
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Are you sure the coolant return line from the back of the heads is connected in the correct radiator port? If they are mixed up it'll do what you described. Also, as stated, you must use the bleeder screws to your advantage. A final note, please do not keep the engine running until it maxes out the temp gauge. You could be looking at warped cylinder heads and/or blown head gasket(s).
Also, if the water pump temp sensor is not reading within parameters the PCM will go into open loop and the fans will engage since it has no temperature information. You should be able to hear the fans easily if they are operational especially if you are pegging the temp gauge. The sensor in the head is only connected to the temp gauge in the cluster.
Also, if the water pump temp sensor is not reading within parameters the PCM will go into open loop and the fans will engage since it has no temperature information. You should be able to hear the fans easily if they are operational especially if you are pegging the temp gauge. The sensor in the head is only connected to the temp gauge in the cluster.
04-02-2018, 07:54 PM
#18
Okay so 1.2k miles ago I had a shop replace my waterpump as well as thermostat, And brand new battery. 1 week ago I went for a 10 minute drive and the car within 4 minutes pegged the temp gauge Passed 260 and lost about 3 gal of antifreeze out of the overflow fill.
I assumed they used the wrong thermostat so I swapped the tstat, refilled and purged both lines untill radiator was full and I can see the antifreeze flowing through the radiator which leads me to beleive that the waterpump is working as well as the radiator and tstat.
Still the car at idle (Too afraid to drive and crack the block) is still pegged on overheat after 4 mim at dead idle, side note battery keeps dying (Which again is brand new). I have also checked the 3 relays for the two fans by replacing them and the one 10amp fuse is not burnt out either, Block seems to be holding the antifreeze now. Only thing I can think of is fans on turning on, I cant get under the car to check and too afraid to slice my fingers.
whats next, Im assuming since the battery keeps dying after a day that there is a short somwhere, (but I wouldnt even know where to begin. (No idea how to find a short) Either that or the temp sensor on the back of the water pump needs to be replaced. Am I on the right path? Or any suggestions?
I assumed they used the wrong thermostat so I swapped the tstat, refilled and purged both lines untill radiator was full and I can see the antifreeze flowing through the radiator which leads me to beleive that the waterpump is working as well as the radiator and tstat.
Still the car at idle (Too afraid to drive and crack the block) is still pegged on overheat after 4 mim at dead idle, side note battery keeps dying (Which again is brand new). I have also checked the 3 relays for the two fans by replacing them and the one 10amp fuse is not burnt out either, Block seems to be holding the antifreeze now. Only thing I can think of is fans on turning on, I cant get under the car to check and too afraid to slice my fingers.
whats next, Im assuming since the battery keeps dying after a day that there is a short somwhere, (but I wouldnt even know where to begin. (No idea how to find a short) Either that or the temp sensor on the back of the water pump needs to be replaced. Am I on the right path? Or any suggestions?
This solved the problem until I developed a leak near my reservoir. I discovered a few days ago in preparation for replacing my optispark that the damn sensor literally blew out from the back. The remanufactured sensor was glued back together and the damn back blew out from coolant pressure! I found my old GM sensor that I never threw out, swapped the newer seals over to it, teflon taped it for snug fit, and hopefully the sensor won't give off that dreaded low coolant light because it is shorted out or something!
Check your hoses for any possible bubbling of coolant, rubber does go bad, if your water pump was leaking I am sure you would know, the reservoir tubing may be leaking but if you already removed your battery, you would discover the pooling of coolant.
I would also check your radiator tanks for any cracks. Mine blew out one winter and I overheated my motor, on top of other dumb things I did with that stock motor, DIY no-nos. When I get my car overhauled to like new in several years, she is getting a full metal radiator, no cheap half-plastic/half-metal crap.
Last edited by Phoenix'97; 04-02-2018 at 08:12 PM.
04-05-2018, 11:54 AM
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I would also check your radiator tanks for any cracks. Mine blew out one winter and I overheated my motor, on top of other dumb things I did with that stock motor, DIY no-nos. When I get my car overhauled to like new in several years, she is getting a full metal radiator, no cheap half-plastic/half-metal crap.
On to the overheating, they said the fans ARE kicking on but that its the Radiator that needs to be replaced. With labor on finding that which was killing my battery and replacing radiator and temp gauge sensor, They said I should get the car back tomorrow . Cost: 699.99 although he would take 10% off labor cost for being a veteran. I just hope they are right about it.
