96 Running Hot
Thread Starter
Cruising
Joined: Sep 2006
Posts: 13
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From: Katy Texas
96 Running Hot
I'm sorry, I searched and I can't find the answer I'm looking for. My brother just bought a 96 Vette and the fans are not coming on by themselves. They will come on with the a/c on but otherwise he says it will go up close to 260 before he has to shut it down with no reaction from the fans...would the a/c still kick the fans on if the relays were bad?
I have found this and from this I have made that assumption. Please correct me if I'm wrong...
"From the 1996 GM manual
"the PCMwill command low speed fans ON at 219F and OFF at 207F and, high speed ON at 228F and OFF at 214F"
....when relay 1 is energized both fans run in low speed, when all three relays are energized both fans run at high speed...
also fans run with a/c on
There are two fans, they are either both on or off, if on they run either low speed or high speed... "
http://forums.corvetteforum.com/show....php?t=1689029
I really appreciate any suggestion or advice.
Thanks!
Shawn
I have found this and from this I have made that assumption. Please correct me if I'm wrong...
"From the 1996 GM manual
"the PCMwill command low speed fans ON at 219F and OFF at 207F and, high speed ON at 228F and OFF at 214F"
....when relay 1 is energized both fans run in low speed, when all three relays are energized both fans run at high speed...
also fans run with a/c on
There are two fans, they are either both on or off, if on they run either low speed or high speed... "
http://forums.corvetteforum.com/show....php?t=1689029
I really appreciate any suggestion or advice.
Thanks!
Shawn
Safety Car
Joined: Sep 2000
Posts: 3,524
Likes: 4
From: Hinckley Ohio
I tied to respond to your PM and I get message saying I can't send you a PM???
The description is a direct quote from my 1996 GM Corvette Service Manual and accordingly ought to be correct..
My first quick thought is to verify the temperature sensors.....are both the analog and digital readouts functioning and in agreement with each other???? Where is the 260 reading?? digital or analog??? I would start here first and make sure the PCM is getting a correct temperature signal.
Good luck...
The description is a direct quote from my 1996 GM Corvette Service Manual and accordingly ought to be correct..
My first quick thought is to verify the temperature sensors.....are both the analog and digital readouts functioning and in agreement with each other???? Where is the 260 reading?? digital or analog??? I would start here first and make sure the PCM is getting a correct temperature signal.
Good luck...
Race Director
Joined: Oct 2005
Posts: 11,771
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From: Rolla Missouri
2021 C4 of the Year - Unmodified Finalist
St. Jude Donor '10 thru '25
I'd verify that's it's really getting to 260 first. If you are looking at the analog temp gauge, you will think it's at 260 when in fact the temp is closer to 230.
What does the digital temp gauge read?
Look close at the analog gauge, and you'll notice the shaded area at the upper end.
The needle will be just about to enter the shaded area with the digital gauge reading in the upper 220's.
The fans will not come on until you reach approx. 228 F.
So, before you panic make sure it's really getting too hot. All new Corvette owners go through this same learning experience.
These cars just run hotter than any other car your used to.
Of course if your really getting that hot, then you have a problem. But check your digital gauge first.
What does the digital temp gauge read?
Look close at the analog gauge, and you'll notice the shaded area at the upper end.
The needle will be just about to enter the shaded area with the digital gauge reading in the upper 220's.
The fans will not come on until you reach approx. 228 F.
So, before you panic make sure it's really getting too hot. All new Corvette owners go through this same learning experience.
These cars just run hotter than any other car your used to.
Of course if your really getting that hot, then you have a problem. But check your digital gauge first.
Thread Starter
Cruising
Joined: Sep 2006
Posts: 13
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From: Katy Texas
I appreciate all of the feedback. My brother is going to try comparing the two readings on his way home this afternoon now that we've realized what everybody was talking about with the digital gauge. I thought everybody has been refering to a handheld diagnostics tool or something. I didn't know the Vette had the digital guage. I will post our findings.
Thanks,
Shawn
Thanks,
Shawn
Race Director
Joined: Oct 2005
Posts: 11,771
Likes: 177
From: Rolla Missouri
2021 C4 of the Year - Unmodified Finalist
St. Jude Donor '10 thru '25
I appreciate all of the feedback. My brother is going to try comparing the two readings on his way home this afternoon now that we've realized what everybody was talking about with the digital gauge. I thought everybody has been refering to a handheld diagnostics tool or something. I didn't know the Vette had the digital guage. I will post our findings.
Thanks,
Shawn
Thanks,
Shawn
Unless the car is moving, there is no airflow across the radiator.
At any speed above approx. 40mph, you should see normal temps. in the 190-195 range.
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Thread Starter
Cruising
Joined: Sep 2006
Posts: 13
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From: Katy Texas
Fans came on at 228 as said (according to the digital gauge). Thank you all so much. The analog gauge was reading about 250 or so. I don't know if it would help to change out the temp sensors to make this one read a little more accurate but at least we know for sure the fans are coming on.
Thanks again,
Shawn
Thanks again,
Shawn
Race Director
Joined: Oct 2005
Posts: 11,771
Likes: 177
From: Rolla Missouri
2021 C4 of the Year - Unmodified Finalist
St. Jude Donor '10 thru '25
Fans came on at 228 as said (according to the digital gauge). Thank you all so much. The analog gauge was reading about 250 or so. I don't know if it would help to change out the temp sensors to make this one read a little more accurate but at least we know for sure the fans are coming on.
Thanks again,
Shawn
Thanks again,
Shawn
That analog temp gauge causes more concern than just about any part on the Corvette (excluding the OptiSpark). We'll save that issue for later.
Safety Car
Joined: Sep 2000
Posts: 3,524
Likes: 4
From: Hinckley Ohio
I am shocked!!!!
What we are saying is that the GM service manual is incorrect!!!! I doubt it!!
I wonder if the fans came on at high speed or low speed???
Per the book they should have come on low speed at 219 and then jumped to high speed at 228.
Don't have time to dig in to it now, but I suspect there is a problem with the low speed fan operation!!!!!
Probably a bad relay contact..there are three relays involved in the cooling fan control.
BTW my car has never seen a temperature anywhere near 228...
What we are saying is that the GM service manual is incorrect!!!! I doubt it!!
I wonder if the fans came on at high speed or low speed???
Per the book they should have come on low speed at 219 and then jumped to high speed at 228.
Don't have time to dig in to it now, but I suspect there is a problem with the low speed fan operation!!!!!
Probably a bad relay contact..there are three relays involved in the cooling fan control.
BTW my car has never seen a temperature anywhere near 228...
Last edited by LT4BUD; Sep 11, 2008 at 10:01 AM.
Le Mans Master
Joined: Feb 2000
Posts: 9,715
Likes: 27
From: Kempner Texas
Remember, too, that the analog (needle) gauge is NOT linear. So, with only a couple of exceptions, you really can't tell what the actual coolant temperature is by looking at the analog gauge.
The Owner's Manual addresses the non-linear point.
Jake
The Owner's Manual addresses the non-linear point.
Jake
Safety Car
Joined: Sep 2000
Posts: 3,524
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From: Hinckley Ohio
Remember the fans are on anytime the A/C is on......I almost always have either the A/C, the vent or the defrost/heat on----the A/C is running in all these modes so the cooling fans are always on so the temperature should rarely get much above the thermostat opening..
Plus about a year after I got the car I changed to a 160 stat and reprogrammed fans----personally I have never looked back regarding the lower temperatures
BTW I still think his fans are malfunctioning since they didn't come on until 228, they should have come on low speed at 219???
Plus about a year after I got the car I changed to a 160 stat and reprogrammed fans----personally I have never looked back regarding the lower temperatures
BTW I still think his fans are malfunctioning since they didn't come on until 228, they should have come on low speed at 219???
Le Mans Master
Joined: Feb 2000
Posts: 9,715
Likes: 27
From: Kempner Texas
All three 96s I've had - the one I have now, one I previously owned and my son's - all showed the same analog temp readings and performance.
Without the A/C 'On' the analog gauge, under certain conditions, would show readings with the needle very close to the little hash-marked box area on the gauge. This would lead one to assume that the coolant temp was closing in on 250F (+/-) since the needle would be very close to the 260 hash mark box, but this isn't the case.
Remember, the gauge isn't linear so even though the needle is very close to the little hash-marked box, the actual temp isn't out of the acceptable range. If all's working as it should, you'll get a red Check Gauges light once the coolant temp gets too high, which I believe is at 260F.
Also, my 96 Owner's Manual cautions that the gauges are designed based on an assumed 50/50 mixture of anti-freeze/water. If that ratio is altered to, say, something like 60/40, the temp readings could/would be inaccurate.
Jake
Without the A/C 'On' the analog gauge, under certain conditions, would show readings with the needle very close to the little hash-marked box area on the gauge. This would lead one to assume that the coolant temp was closing in on 250F (+/-) since the needle would be very close to the 260 hash mark box, but this isn't the case.
Remember, the gauge isn't linear so even though the needle is very close to the little hash-marked box, the actual temp isn't out of the acceptable range. If all's working as it should, you'll get a red Check Gauges light once the coolant temp gets too high, which I believe is at 260F.
Also, my 96 Owner's Manual cautions that the gauges are designed based on an assumed 50/50 mixture of anti-freeze/water. If that ratio is altered to, say, something like 60/40, the temp readings could/would be inaccurate.
Jake