Yet another heating/cooling issue...
kidd94
10-07-2005, 12:37 PM
Ok, I have a 96. The other day the upper radiator developed a leak.
When I stopped the car, I did releive the pressure in the system by slowly turning the resevoir cap. Later that evening, after it had cooled down considerably, (never overheated), I drove about 15 mins. to pick up the new hose for the car. While I drove to autozone, the temp never went above 200 degrees. Prior to the hose, the car would typically always run in the city btween the hash's below the redzone. Only on cool days and highway driving would the car go below 200 degrees. I noticed that with the low coolant indicator going that the fans now run continuously the temperature is perfect. I replaced the hose and topped off the fluid so that it is just at the level where I get the indicator to come on, so that the fans blow all the time. Temperature is perfect.
I also replaced the overflow resevoir cap as well. I thought maybe the cap was not releiving the pressure in the system thus causing 2 radiators in 2 years (I know, I should have done the cap along time ago) and now a upper hose.
Right now the temp has never been better. No leaks and no overheating.
I am afraid that if I top off the coolant bottle that the fans will not kick on again (which I don't think they have been coming on soon enough anyways).
Will a bad cap cause the car to overheat or run too hot if it is not relieving pressure and cause hoses and even radiators to crack.
When I stopped the car, I did releive the pressure in the system by slowly turning the resevoir cap. Later that evening, after it had cooled down considerably, (never overheated), I drove about 15 mins. to pick up the new hose for the car. While I drove to autozone, the temp never went above 200 degrees. Prior to the hose, the car would typically always run in the city btween the hash's below the redzone. Only on cool days and highway driving would the car go below 200 degrees. I noticed that with the low coolant indicator going that the fans now run continuously the temperature is perfect. I replaced the hose and topped off the fluid so that it is just at the level where I get the indicator to come on, so that the fans blow all the time. Temperature is perfect.
I also replaced the overflow resevoir cap as well. I thought maybe the cap was not releiving the pressure in the system thus causing 2 radiators in 2 years (I know, I should have done the cap along time ago) and now a upper hose.
Right now the temp has never been better. No leaks and no overheating.
I am afraid that if I top off the coolant bottle that the fans will not kick on again (which I don't think they have been coming on soon enough anyways).
Will a bad cap cause the car to overheat or run too hot if it is not relieving pressure and cause hoses and even radiators to crack.
tjm
10-07-2005, 04:05 PM
the system NEEDs the pressure to keep cool as liquid under pressure has a significantly higher boiling point.
Too much pressure blows hoses, radiator and gaskets. Not enough pressure will allow expansion of the coolant, overflow, end up with not enough coolant and then make the car run hot.
Too much pressure blows hoses, radiator and gaskets. Not enough pressure will allow expansion of the coolant, overflow, end up with not enough coolant and then make the car run hot.
kidd94
10-07-2005, 08:44 PM
the system NEEDs the pressure to keep cool as liquid under pressure has a significantly higher boiling point.
Too much pressure blows hoses, radiator and gaskets. Not enough pressure will allow expansion of the coolant, overflow, end up with not enough coolant and then make the car run hot.
Is it possible then that the cooling fans are keeping the car running that much cooler?
Prior to replacing the upper radiator hose when the fans kicked in, they never really seemed to drop the temp, only kept it stable.
Is the cap the only device (if that is the correct word to define the cap) that relieves the pressure.
After I replaced the hose and topped of the coolant I let the car run for about 20 mins with the cap off. Then I put the cap on and took the car for a spin. During the drive the car started to heat up like it normally would in the past and was running inbetween the hashes just below the red zone. Then I am assuming that the thermostat opened and took coolant from the resevoir. As soon as it did that, the "low coolant indicator" came on, and then the temp dropped real fast and then ran below 200 degrees with the fans running. The car ran all day below 200 degrees for the first time since owning the car 4 1/2 years. I have not topped off the coolant resevoir to where it should be. There is coolant in their but it is below the sensor to get the low coolant reading.
I don't get this car. You would think that it would run under 200 degrees with a full resevoir. But it does not.
Is there a way to check to see at what temp the fans kick on. And do you think it would be a good idea to replaced the Coolant Temp Senor, and does the sensor run the fans.
Too much pressure blows hoses, radiator and gaskets. Not enough pressure will allow expansion of the coolant, overflow, end up with not enough coolant and then make the car run hot.
Is it possible then that the cooling fans are keeping the car running that much cooler?
Prior to replacing the upper radiator hose when the fans kicked in, they never really seemed to drop the temp, only kept it stable.
Is the cap the only device (if that is the correct word to define the cap) that relieves the pressure.
After I replaced the hose and topped of the coolant I let the car run for about 20 mins with the cap off. Then I put the cap on and took the car for a spin. During the drive the car started to heat up like it normally would in the past and was running inbetween the hashes just below the red zone. Then I am assuming that the thermostat opened and took coolant from the resevoir. As soon as it did that, the "low coolant indicator" came on, and then the temp dropped real fast and then ran below 200 degrees with the fans running. The car ran all day below 200 degrees for the first time since owning the car 4 1/2 years. I have not topped off the coolant resevoir to where it should be. There is coolant in their but it is below the sensor to get the low coolant reading.
I don't get this car. You would think that it would run under 200 degrees with a full resevoir. But it does not.
Is there a way to check to see at what temp the fans kick on. And do you think it would be a good idea to replaced the Coolant Temp Senor, and does the sensor run the fans.
tjm
10-07-2005, 09:26 PM
the cap is the only NORMAL place for pressure to be released.
what happens when you warm up the car with the cap of is that the coolant heats up and expands and "falsely" fills the system. then you put the cap on and the therm opens and any trapped air is pushed into the res.
Do this - when the car is cold, top it off only to the mark on the side of the res, put the cap on and run till hot. overnight the car will cool and the coolant will contract. the cap will allow air into the system as it cools. when the engine is cold again top off the system once more to the mark on the side of the res. possibly one more time and you should be good.
The fans are regulated by coolant temp and not coolant level so .... keeping the coolant low just to make the low coolant light come on does nothing control the fans but will make you low on coolant.
replacing the coolant temp sensor may not be a bad idea. typically the first fan will come on at about 230 and the second comes on at about 240 and also when the AC hi, max, rec is on. do what i mentioned above first i think and see if thats all ya need.
my 97 197,000 miles, usually runs just over 200 and will go just above the next line in traffic.
if your thermostat is good OEM or Stant and new and your cap is new and the water pump doesnt leak or make noise and you still have temp probs then ya may need a new rad.
what happens when you warm up the car with the cap of is that the coolant heats up and expands and "falsely" fills the system. then you put the cap on and the therm opens and any trapped air is pushed into the res.
Do this - when the car is cold, top it off only to the mark on the side of the res, put the cap on and run till hot. overnight the car will cool and the coolant will contract. the cap will allow air into the system as it cools. when the engine is cold again top off the system once more to the mark on the side of the res. possibly one more time and you should be good.
The fans are regulated by coolant temp and not coolant level so .... keeping the coolant low just to make the low coolant light come on does nothing control the fans but will make you low on coolant.
replacing the coolant temp sensor may not be a bad idea. typically the first fan will come on at about 230 and the second comes on at about 240 and also when the AC hi, max, rec is on. do what i mentioned above first i think and see if thats all ya need.
my 97 197,000 miles, usually runs just over 200 and will go just above the next line in traffic.
if your thermostat is good OEM or Stant and new and your cap is new and the water pump doesnt leak or make noise and you still have temp probs then ya may need a new rad.
apollo7879
10-08-2005, 05:32 PM
I have read in this forum previously, that you can disconnect the elec connector at the coolant level sensor (bottom of the resevoir) & the fans will run continuously. Good to know, but probably not a good idea to leave disconnected.
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