Overheated
Thread Starter
Instructor
Joined: Apr 2006
Posts: 162
Likes: 0
From: Albany New York
Overheated
Hi guys...today the Vette overheated for no appearnt reason. I was driving on the highway, got off, went into a store. On my way out (maybe 10-15 minutes later) I went to start it and the battery was dead...I thought that was weird, but since my alternator is going out I just figured it was that. So i pop the hood, and notice the trail of coolant coming out of the overflow tank into the parking lot. I opened the cap on the overflow tank and it was to the top, literally boiling. So I let that cool off a little while.
By the time I got the jump start (again, another 10 minutes) the temperature guage was reading about 235. I turned on the heat, and attempted to make it home. About 15 minutes into the drive, it started climbing rapidly at rates of 5 degrees every time the temp. guage refreshes. It went to 275, the red light came on, and I immediatly pulled over and shut it off. Since I have free towing on my insurance, I decided not to take any chances and got it towed home. It sits in my driveway.
Any ideas? Thanks!
By the time I got the jump start (again, another 10 minutes) the temperature guage was reading about 235. I turned on the heat, and attempted to make it home. About 15 minutes into the drive, it started climbing rapidly at rates of 5 degrees every time the temp. guage refreshes. It went to 275, the red light came on, and I immediatly pulled over and shut it off. Since I have free towing on my insurance, I decided not to take any chances and got it towed home. It sits in my driveway.
Any ideas? Thanks!
Team Owner
Joined: Jun 2005
Posts: 46,295
Likes: 2,596
From: Northern, VA
St. Jude Donor '15
"In honor of jpee"
Start at the beginning: car, year, miles, what's been done to the car re replacements, repairs?
Alternator going out, fans working/not working? Battery shot, too? Frozen/slipping pulley? Frozen, you'd hear it. Slipping, you might not. Any charging issues (must be if alt.'s going out) like less than 14?
Then comes a myriad of issues re cooling: belt, fans, hoses, radiator itself., fluid changed recently, temp sending unit, thermo, rad cap, sufficient fluid in reservoir (clear plastic), dirt/gunk/leaves betw. condensor/rad., etc.
Forgot, waterpump? HOw many miles on car? When's last time wp was changed?
Alternator going out, fans working/not working? Battery shot, too? Frozen/slipping pulley? Frozen, you'd hear it. Slipping, you might not. Any charging issues (must be if alt.'s going out) like less than 14?
Then comes a myriad of issues re cooling: belt, fans, hoses, radiator itself., fluid changed recently, temp sending unit, thermo, rad cap, sufficient fluid in reservoir (clear plastic), dirt/gunk/leaves betw. condensor/rad., etc.
Forgot, waterpump? HOw many miles on car? When's last time wp was changed?
Last edited by AORoads; Jun 13, 2006 at 11:22 PM.
Thread Starter
Instructor
Joined: Apr 2006
Posts: 162
Likes: 0
From: Albany New York
1986 Vette, automatic. 130k miles. As far as whats been done to it, I have no records and no way of knowing.
Originally Posted by LT4CompYell
Start at the beginning: car, year, miles, what's been done to the car re replacements, repairs?
Alternator going out,
Advance auto parts told me that it was on its way out, they said it wasnt making enough power, but just the bare minimum.
fans working/not working?
-working
Battery
-new
Frozen/slipping pulley? Frozen, you'd hear it.
Slipping,
-dont hear anything
you might not. Any charging issues (must be if alt.'s going out) like less than 14?
-yes, it is charging less than 14 amps, I beleive he might have said 9?
Then comes a myriad of issues re cooling: belt, fans, hoses,
-belts and hoses look ok...
radiator itself
-radiator looks as if it may have been replaced, there is no sticker on the side where it tells you how to set the timing(I know this because i needed that sticker)
fluid changed recently
-no idea when the fluid was changed, it was looking brown/black in color before this happend( I know its bad, I didnt have enough time to change it and it was running at a steady 180-190 degrees)
, temp sending unit, thermo, rad cap, sufficient fluid in reservoir (clear plastic), dirt/gunk/leaves betw. condensor/rad., etc.
Forgot, waterpump? HOw many miles on car? When's last time wp was changed?
Alternator going out,
Advance auto parts told me that it was on its way out, they said it wasnt making enough power, but just the bare minimum.
fans working/not working?
-working
Battery
-new
Frozen/slipping pulley? Frozen, you'd hear it.
Slipping,
-dont hear anything
you might not. Any charging issues (must be if alt.'s going out) like less than 14?
-yes, it is charging less than 14 amps, I beleive he might have said 9?
Then comes a myriad of issues re cooling: belt, fans, hoses,
-belts and hoses look ok...
radiator itself
-radiator looks as if it may have been replaced, there is no sticker on the side where it tells you how to set the timing(I know this because i needed that sticker)
fluid changed recently
-no idea when the fluid was changed, it was looking brown/black in color before this happend( I know its bad, I didnt have enough time to change it and it was running at a steady 180-190 degrees)
, temp sending unit, thermo, rad cap, sufficient fluid in reservoir (clear plastic), dirt/gunk/leaves betw. condensor/rad., etc.
Forgot, waterpump? HOw many miles on car? When's last time wp was changed?
Thread Starter
Instructor
Joined: Apr 2006
Posts: 162
Likes: 0
From: Albany New York
Also, I assume the max temperature it allows is 275 correct? Because thats when the red light came on. It ran for possibly 5 seconds with the red light on, before I shut it off. Should I worry about having warped anything?
Le Mans Master
Joined: May 2006
Posts: 9,226
Likes: 9
From: Irvine Ca
Fluctuating temps while driving usually means the water pump took a dump. The WP is one of those things that nobody touches until it stops working so the chances that yours is the stocker is pretty good.
If your changing that WP then get the hoses, thermostat, Belt and a new Radiator cap and flush the radiator at the same time.
If your changing that WP then get the hoses, thermostat, Belt and a new Radiator cap and flush the radiator at the same time.
Le Mans Master
Joined: May 2005
Posts: 7,354
Likes: 2,279
From: Central Maryland
Originally Posted by SteveJG
Hi guys...today the Vette overheated for no appearnt reason. I was driving on the highway, got off, went into a store. On my way out (maybe 10-15 minutes later) I went to start it and the battery was dead...I thought that was weird, but since my alternator is going out I just figured it was that. So i pop the hood, and notice the trail of coolant coming out of the overflow tank into the parking lot. I opened the cap on the overflow tank and it was to the top, literally boiling. So I let that cool off a little while.
By the time I got the jump start (again, another 10 minutes) the temperature guage was reading about 235. I turned on the heat, and attempted to make it home. About 15 minutes into the drive, it started climbing rapidly at rates of 5 degrees every time the temp. guage refreshes. It went to 275, the red light came on, and I immediatly pulled over and shut it off. Since I have free towing on my insurance, I decided not to take any chances and got it towed home. It sits in my driveway.
Any ideas? Thanks!
By the time I got the jump start (again, another 10 minutes) the temperature guage was reading about 235. I turned on the heat, and attempted to make it home. About 15 minutes into the drive, it started climbing rapidly at rates of 5 degrees every time the temp. guage refreshes. It went to 275, the red light came on, and I immediatly pulled over and shut it off. Since I have free towing on my insurance, I decided not to take any chances and got it towed home. It sits in my driveway.
Any ideas? Thanks!
Be well,
SJW
Race Director
Joined: Jun 1999
Posts: 14,924
Likes: 9
From: Merritt Ils Fl
FWIW: If you had been seeing normal temps and suddenly have an overheat condition something in the cooling system failed. I would start by making sure all the easy fixes are in place, rad flush,clean coolant, rad clean(between the rad and A/C condenser), hoses in good condition. Pay close attention to the lower hose, when old and weak,especially if the inner wire coil has rusted away, the hose can collapse starving the water pump. Take a close look at your belt. Hard,glazed, could be the cause of your alternator issue. If this preventive maintenance doesn't do the trick swap the stat to a 180 deg. If you still have a problem swap the water pump. A water pump is a very simple impeller type pump. Failure usually comes from the seal or bearing. I have seen one and only one broken impeller in my life. A check on pump action is to watch for water flowing in the rad after the stat has opened.
Good luck.
Good luck.
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Le Mans Master
Joined: May 2005
Posts: 7,354
Likes: 2,279
From: Central Maryland
Originally Posted by SteveJG
Will do today. How hard is it to get to the waterpump on the vette? My other car, the Range Rover, is a full day job.
A sudden overheating condition, where the car previously ran nice and cool, is almost always a result of a broken drive belt, stuck thermostat, inoperative electric cooling fan, obstruction of air flow through the radiator, or loss of coolant. If we toss out the broken belt and loss of coolant (you did say that it didn't leak coolant and that the belt was in place, correct?), that leaves us with the fans, thermostat or obstruction of air flow. Check to see if you sucked a plastic bag, etc up in front of the radiator (C4s are bottom-feeders and will vacuum all sorts of stuff up from the road). If nothing is obstructing air flow, do the fans run? If so, replace the thermostat and see what happens.
Be well,
SJW
Last edited by SJW; Jun 14, 2006 at 10:04 AM.
Le Mans Master
Joined: Oct 2003
Posts: 6,130
Likes: 2
From: seattle WA
I'd definetly check between the radiator and condensor..these C4s are like a Hoover vacumn, they suck up anything and everything. Next, I'd be checking the oil, make sure there's no coolant in it.
Le Mans Master
Joined: May 2006
Posts: 9,226
Likes: 9
From: Irvine Ca
Originally Posted by SJW
If the water pump isn't leaking or showing signs of bearing failure, it would be the last thing I'd look at. Impeller failures on water pumps are exceedingly rare if the pump has been in service for a while.
Le Mans Master
Joined: Aug 2005
Posts: 5,002
Likes: 5
From: No Opti Here Tn
St. Jude Donor '06
Originally Posted by jhammons01
Fluctuating temps while driving usually means the water pump took a dump. The WP is one of those things that nobody touches until it stops working so the chances that yours is the stocker is pretty good.
If your changing that WP then get the hoses, thermostat, Belt and a new Radiator cap and flush the radiator at the same time.
If your changing that WP then get the hoses, thermostat, Belt and a new Radiator cap and flush the radiator at the same time.
Burning Brakes
Joined: Oct 2005
Posts: 798
Likes: 116
From: OAKLEY CA
overheating
My thermostat was stuck in the open position (88 A4, 170 k miles). It could have stuck in the closed position just as well. For your temperature to climb that fast with a full radiator and the belt in place, I would bet on the thermostat. The space between the condenser and radiator is probably full of crap as well. I just posted photos of my fix, if you search for posts under my name you will see it.
Also, as mentioned, check your oil for water, it will be milky if present. If it is normal, you dodged a bullet (new motor). You need to take this baby off the road until you can find the time and money for an alternator, thermostat, belts and hoses, coolant, oil and filter since you do not know when any of this was done. This will be cheaper in the long run. Then you can enjoy your Corvette.
Also, as mentioned, check your oil for water, it will be milky if present. If it is normal, you dodged a bullet (new motor). You need to take this baby off the road until you can find the time and money for an alternator, thermostat, belts and hoses, coolant, oil and filter since you do not know when any of this was done. This will be cheaper in the long run. Then you can enjoy your Corvette.
Le Mans Master
Joined: May 2006
Posts: 9,226
Likes: 9
From: Irvine Ca
Read his first post again.
It said that he was driving with all being well. Stopped for a sanck and when he returned to driving then the temp started fluctuating. A thermostat is not going to move while you are in a 7-11 for a soda. I agree that a thermostat causes most porblems...but they are a light switch on/off.....open/closed.
A slow pumping Water pump would allow higher temps that upon stopping the radiator would begin to boil as the water has now stopped yet the heat exchange/thermal transfer has continued to take place.....the system will then begin to obtain temps that are great enough to start forcing compressed/heated water into the resoivoir and once it reaches atmosphear it begins to boil.
It said that he was driving with all being well. Stopped for a sanck and when he returned to driving then the temp started fluctuating. A thermostat is not going to move while you are in a 7-11 for a soda. I agree that a thermostat causes most porblems...but they are a light switch on/off.....open/closed.
A slow pumping Water pump would allow higher temps that upon stopping the radiator would begin to boil as the water has now stopped yet the heat exchange/thermal transfer has continued to take place.....the system will then begin to obtain temps that are great enough to start forcing compressed/heated water into the resoivoir and once it reaches atmosphear it begins to boil.
Pro
Joined: Aug 2001
Posts: 617
Likes: 14
From: Loudon, TN
As stated earlier, in the vast majority of cases the only thing that fails on a water pump in the bearing or seal. I've worked on cars and trucks for over 40 years and have never seen an impeller on a water pump fail. Don't waste your time/money replacing the pump unless it's leaking. For the temp to get so hot so fast indicates only a couple things to me, a faulty thermostat or a blown headgasket. Replace the thermostat first because it's less than $10.00 and only a few minutes work. If it still overheats then it's time to check for a blown headgasket.
Le Mans Master
Joined: May 2005
Posts: 7,354
Likes: 2,279
From: Central Maryland
Originally Posted by jhammons01
Read his first post again.
It said that he was driving with all being well. Stopped for a sanck and when he returned to driving then the temp started fluctuating. A thermostat is not going to move while you are in a 7-11 for a soda. I agree that a thermostat causes most porblems...but they are a light switch on/off.....open/closed.
A slow pumping Water pump would allow higher temps that upon stopping the radiator would begin to boil as the water has now stopped yet the heat exchange/thermal transfer has continued to take place.....the system will then begin to obtain temps that are great enough to start forcing compressed/heated water into the resoivoir and once it reaches atmosphear it begins to boil.
It said that he was driving with all being well. Stopped for a sanck and when he returned to driving then the temp started fluctuating. A thermostat is not going to move while you are in a 7-11 for a soda. I agree that a thermostat causes most porblems...but they are a light switch on/off.....open/closed.
A slow pumping Water pump would allow higher temps that upon stopping the radiator would begin to boil as the water has now stopped yet the heat exchange/thermal transfer has continued to take place.....the system will then begin to obtain temps that are great enough to start forcing compressed/heated water into the resoivoir and once it reaches atmosphear it begins to boil.
First thing I'd look for would be an airflow obstruction, or inop cooling fan(s).
I still don't think it's the pump...
Be well,
SJW
Thread Starter
Instructor
Joined: Apr 2006
Posts: 162
Likes: 0
From: Albany New York
Wow...thanks for all the replies! I am just about to go insepct it, I have been busy since yesterday, and now I finally have free time. First thing I will do is check for obstructions, then flush the coolant and top off with new. I did think to check the oil yesterday after it happened, and it was fine (no coolant).
I bet headgaskets are a bitch on a v8...ive only done one on a 4 cylinder. I really dont beleive that is my problem though. I do have a question. GM must have said its ok for the motor to run all the way up to 275..because thats when the red light came on. Obvioulsy it is not good, but you think that what seems like GM's maximum number (275) could have blown a HG?
I bet headgaskets are a bitch on a v8...ive only done one on a 4 cylinder. I really dont beleive that is my problem though. I do have a question. GM must have said its ok for the motor to run all the way up to 275..because thats when the red light came on. Obvioulsy it is not good, but you think that what seems like GM's maximum number (275) could have blown a HG?
Le Mans Master
Joined: May 2005
Posts: 7,354
Likes: 2,279
From: Central Maryland
Originally Posted by SteveJG
Wow...thanks for all the replies! I am just about to go insepct it, I have been busy since yesterday, and now I finally have free time. First thing I will do is check for obstructions, then flush the coolant and top off with new. I did think to check the oil yesterday after it happened, and it was fine (no coolant).
I bet headgaskets are a bitch on a v8...ive only done one on a 4 cylinder. I really dont beleive that is my problem though. I do have a question. GM must have said its ok for the motor to run all the way up to 275..because thats when the red light came on. Obvioulsy it is not good, but you think that what seems like GM's maximum number (275) could have blown a HG?
I bet headgaskets are a bitch on a v8...ive only done one on a 4 cylinder. I really dont beleive that is my problem though. I do have a question. GM must have said its ok for the motor to run all the way up to 275..because thats when the red light came on. Obvioulsy it is not good, but you think that what seems like GM's maximum number (275) could have blown a HG?
I would proceed exactly as you've planned, with the possible exception of also swapping out the thermostat while you've got the cooling system opened up anyway.
Let us know what you find.
Be well,
SJW