Overheating 93
Thread Starter
Intermediate
Joined: Jul 2003
Posts: 27
Likes: 0
From: Atlanta Georgia
Overheating 93
Hey there,
I am trying to get a friends 93 vette back in order for him and we are having some overheating problems. I have done the normal quick stuff...changed thermostat, cleaned and flushed radiator, and cleaned in between condensor and radiator but the problem persists. I have noticed that the fans are supposed to come on at different temps (from reading other posts) but can not get the second fan to come on ( I know this is a problem) The first fan comes on at 225* and if I kick the A/C on both fans come on. With both fans on the car still runs Hot 240*+ How hot is to hot? I understand the vettes run hotter, but just how hot is it supposed to get, what temp should the second fan (passenger side) kick on and where is the sensor for it.
I know this is long but any help would be greatly appreciated!!!
I am trying to get a friends 93 vette back in order for him and we are having some overheating problems. I have done the normal quick stuff...changed thermostat, cleaned and flushed radiator, and cleaned in between condensor and radiator but the problem persists. I have noticed that the fans are supposed to come on at different temps (from reading other posts) but can not get the second fan to come on ( I know this is a problem) The first fan comes on at 225* and if I kick the A/C on both fans come on. With both fans on the car still runs Hot 240*+ How hot is to hot? I understand the vettes run hotter, but just how hot is it supposed to get, what temp should the second fan (passenger side) kick on and where is the sensor for it.
I know this is long but any help would be greatly appreciated!!!
Safety Car
Joined: Aug 2002
Posts: 3,842
Likes: 230
From: SANTA CRUZ CA
Re: Overheating 93 (newtovettes)
Basics...The ECM will activate the primary cooling fan based on input from the ECT (engine coolant temperature sensor). The fan will turn "on" when the coolant temp exceeds 226 or the oil temp exceeds 228. The fan will remain "on" until the temp has dropped approx. 36 deg. The secondary fan is controlled by the ECM based on inputs from the A/C system, engine coolant temp sensor, vehicle speed sensor and RPMs. The secondary fan will be turned "on" when the coolant temp exceeds 234 or the engine oil at 235, and will remain "on" until the temp drops approx. 36 deg.
Does the vette run 195 -205 normal driving....not stop-and-go?
Does the vette run 195 -205 normal driving....not stop-and-go?
Thread Starter
Intermediate
Joined: Jul 2003
Posts: 27
Likes: 0
From: Atlanta Georgia
Re: Overheating 93 (Oldman)
It runs between 205-220 under normal driving (above 40mph), the second fan does not kick on even up to 240+. The second fan does come on when the A/C is on. The temp has only seemed to rise since summer temps arrived, but even yesterday when temps stayed around 80* the temp went up to 240* but would not rise any higher. The secondary fan never came on. I turned the A/C on and the temp dropped to 218* when the A/C was turned off the primary fan also shut down. Last week when temps were in the 90's it got up to 258* before traffic allowed him to move and the temp came back to normal. That was with the A/C on so both fans were running.
Safety Car
Joined: Aug 2002
Posts: 3,842
Likes: 230
From: SANTA CRUZ CA
Re: Overheating 93 (newtovettes)
If the engine is actually overheating and the gage indicates overheating, but the cooling fan is not coming "on", the Engine Coolant Temperature (ECT) sensor has probably shifted out of calibration and should be replaced. Here is a link for the sensor location: http://www.c4vettes.com/sensorinformation.htm
The sensor may not be the only problem, as 205-220 at "speed" is too high. I just returned from a trip with temps in the mid-90s, and coolant temp was at 200 (stock tstat, etc.). I'll do some more research..........
[Modified by Oldman, 1:54 PM 7/24/2003]
The sensor may not be the only problem, as 205-220 at "speed" is too high. I just returned from a trip with temps in the mid-90s, and coolant temp was at 200 (stock tstat, etc.). I'll do some more research..........
[Modified by Oldman, 1:54 PM 7/24/2003]
Thread Starter
Intermediate
Joined: Jul 2003
Posts: 27
Likes: 0
From: Atlanta Georgia
Re: Overheating 93 (Oldman)
Thanks, that will be a very valuable link.
I thought that was to high as well, but I was told vettes run a lot hotter than "normal" cars. Who knows, seems like if Chevy wanted to keep the temp below 205 the fan/ fans would kick on sooner than 225/238 but then again I am not an engineer :D
Thanks again for the help. I think the next thing for me to do is remove the radiator and clean it good.
I thought that was to high as well, but I was told vettes run a lot hotter than "normal" cars. Who knows, seems like if Chevy wanted to keep the temp below 205 the fan/ fans would kick on sooner than 225/238 but then again I am not an engineer :D
Thanks again for the help. I think the next thing for me to do is remove the radiator and clean it good.
Safety Car
Joined: Aug 2002
Posts: 3,842
Likes: 230
From: SANTA CRUZ CA
Re: Overheating 93 (newtovettes)
Vettes run a little hotter for smog purposes..........
A failure in the ECT circuit should set either a DTC (diagnostic trouble code) 14 or 15. Use that same link I sent you for retrieving trouble codes.
A note: the cooling system must be bled after draining and refilling. There are two brass bleed screws located on the passenger side of the engine just below the air intake. When bleeding the coolant system, be sure and pack that area with rags to prevent any spillage of coolant onto/into the opit-spark unit. If you need a pic of the screws, I can email it to you.
[Modified by Oldman, 2:15 PM 7/24/2003]
A failure in the ECT circuit should set either a DTC (diagnostic trouble code) 14 or 15. Use that same link I sent you for retrieving trouble codes.
A note: the cooling system must be bled after draining and refilling. There are two brass bleed screws located on the passenger side of the engine just below the air intake. When bleeding the coolant system, be sure and pack that area with rags to prevent any spillage of coolant onto/into the opit-spark unit. If you need a pic of the screws, I can email it to you.
[Modified by Oldman, 2:15 PM 7/24/2003]
Thread Starter
Intermediate
Joined: Jul 2003
Posts: 27
Likes: 0
From: Atlanta Georgia
Re: Overheating 93 (Oldman)
Actually the guy took it to a shop who charged him $90 to flush the system and another $180 to change the thermostat and belt. I was just advising him at that point, now that he got screwed he decided I might be better than the shop. I will check those bleed screws though, a picture would be great if you have one handy.
There is not a check engine light on...should there be for this problem or does it just store the codes?
Thanks
There is not a check engine light on...should there be for this problem or does it just store the codes?
Thanks
Safety Car
Joined: Aug 2002
Posts: 3,842
Likes: 230
From: SANTA CRUZ CA
Re: Overheating 93 (newtovettes)
The "check engine" light should be displayed when a fault code is detected. But it may not remain "on". Also, we are assuming that the temp gage is accurate. The gage accuracy can be checked by comparing the ECT sensor reading using a scan tool and comparing its' reading with the gage reading.
Bleed screw location pic is from the owners manual, page 219, which is not very clear. If that manual is available, the original may be more clear than the pic I am sending you.
Bleed screw location pic is from the owners manual, page 219, which is not very clear. If that manual is available, the original may be more clear than the pic I am sending you.
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Thread Starter
Intermediate
Joined: Jul 2003
Posts: 27
Likes: 0
From: Atlanta Georgia
Re: Overheating 93 (Oldman)
Owners manual has been lost, that pick will definitely help. I will have a chance to take a look at the car again on Saturday. I believe iut to be an accurate reading, because fan 1 comes on dead on 225*...or is the same sensor running both. Well if thats the case I guess I really dont know. :D
Than ks again for the help I'll keep you posted if...ummm when I get it worked out!!! :D :D :cheers:
Than ks again for the help I'll keep you posted if...ummm when I get it worked out!!! :D :D :cheers:
