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looking for advise 94 heating up thought it was thermostat turned the air on so both fans would run bled both bleeders it idiled in the garage for 40 to 45 min stayed at about 185 drove it then it started running hot again any advice would be appreciated car has 60 thousand miles on it
looking for advise 94 heating up thought it was thermostat turned the air on so both fans would run bled both bleeders it idiled in the garage for 40 to 45 min stayed at about 185 drove it then it started running hot again any advice would be appreciated car has 60 thousand miles on it
What are you calling hot? When you changed the stat did you do a flush? Are you sure the radiator is clear?
First, use your digital read out, not the analoge. The primary fan is on at 228 and the secondary at 230. If it gets to 231/232 and continues to rise, there is an issue.
"....thought it was thermostat turned the air on so both fans would run bled both bleeders"......
The t-stat is just a valve, it doesn't do anything but open and close based on coolant temp.
The digital temp sensor, located in the water pump, works with the ecm to control the fans, not the bleed screws. The bleed screws are manually turned, but are unnecessary in the LT1 engine, as it bleeds itself.
"....thought it was thermostat turned the air on so both fans would run bled both bleeders"......
The t-stat is just a valve, it doesn't do anything but open and close based on coolant temp.
The digital temp sensor, located in the water pump, works with the ecm to control the fans, not the bleed screws. The bleed screws are manually turned, but are unnecessary in the LT1 engine, as it bleeds itself.
red line hot both fans were running at idle and staying around 185
red line hot both fans were running at idle and staying around 185
Things are not consistent ......red line hot (analog gage?) temp around 185 (digital gage?) both fans running and temp at 185?
Fans activate at about 226 primary & 236 both..... fans shut off at
about 217, so your temp cannot be 185. If that reading is from the analog sensor, replace the sensor.
What is the coolant level.... reservoir & overflow bottle?
(don't check expansion reservoir when hot!!!)
185 read out on digital is great! These motors run hot. You are looking at the digital # arent you?
yes I am I guess so how do I check the other one also I was told by a restoration place the second fan doesn't turn on until the air conditioner is on I just don't get it that it was fine at idle and not when driving so 4 core radiator
okay so that's not true the second fan wont turn on until the air is on now what
the second fan is turned on by the ecm when the digital temp sensor reaches about 236f.
Coolant temp is controlled by air flow and coolant flow.... that simple..... block one, or both, and you will
have overheating. If the fans don't reduce the temp from about 236F to 217, then there is either insufficient coolant
in the system, or lack of coolant movement (water pump). You need to ensure that the air passage to the radiator
is clear, there is sufficient (full) coolant in the system, there are no air leaks into the system (split hose ends, radiator
cap gasket distorted or torn, loose clamps). If air enters the system, the pressurization is negated, and the boiling
temp remains at 212, rather than at 260F (16# cap increases boiling temp to about 260 (3deg per#).
the second fan is turned on by the ecm when the digital temp sensor reaches about 236f.
okay cool thanks for the advice now that's the one on the water pump not the one on the right side of motor im also thinking needs flush r just go 4 cor radiator also damn emisions I don't have to have it hear on a 94
First, we need to know the temperature shown on the digital readout, not the analog gauge.
The digital temperature comes from the sensor on the waterpump.
The analog gauge gets its information from the sensor on the right side of the head.
On a 1992 the first fan comes on at 229 and the second fan comes on at 239F. I think that on a 1994 both fans come on at low speed at about 229 and then go to high speed around 239. I do not recall exactly when the change was made.
If you turn on the A/C I think both fans should run even if the engine temp is below 229.
Here is a photo of a sticker that came on all the later C4 Corvettes.
First, we need to know the temperature shown on the digital readout, not the analog gauge.
The digital temperature comes from the sensor on the waterpump.
The analog gauge gets its information from the sensor on the right side of the head.
On a 1992 the first fan comes on at 229 and the second fan comes on at 239F. I think that on a 1994 both fans come on at low speed at about 229 and then go to high speed around 239. I do not recall exactly when the change was made.
If you turn on the A/C I think both fans should run even if the engine temp is below 229.
Here is a photo of a sticker that came on all the later C4 Corvettes.
okay by the gauge on the dash it goes to damn near 260 if the air isn't on only one fan turns on how do I tell what the other temp is
the digital temp gage button is activated but the button near the fuel button.
You may have several problems:
You never mentioned coolant level in either reservoir - expansion reservoir & overflow bottle. Coolant needs to flow when hot and during cool down.
If the t-stat has failed in the shut position, no coolant flow.
If the digital temp sensor has failed, no fan activation.
If you have an Owner's Manual, refer to for gage button info.
I believe the analog gauge will be near the red area when the coolant is around 230 degrees.
It sounds like the first thing you need to do is read the owners manual. If you do not have one you can get one online.
If you press the gauge button it will cycle through functions such as oil temp., generator, water temp., etc. This is the temperature you will rely on.
While the car is cold, check the level of coolant in the main reservoir and in the recovery tank. The main should be full and the recovery tank should be at the cold mark on the dipstick.
Drive the car and watch the digital temp, with the A/C OFF. It should stay around 200 while going down the road. When stopped it will climb until the fans kick on, around 229F. At that point the temps should start dropping. If the temps continue to climb, get off the road, open the hood and verify that the fans are running.
Let us know how it goes. Remember, we need definite facts, not " It got hot".
okay by the gauge on the dash it goes to damn near 260 if the air isn't on only one fan turns on how do I tell what the other temp is
Until you post up what what the "digital" temp gauge is reading, you don't really know if your car is running hot or not.
That analog gauge needle just scares the crap out of new owners.
Look at that gauge real close, and you might notice that the needle doesn't actually reach the 260 mark. The needle stops just before reaching the shaded area.
1994 running hot
