1997 Aurora--Running very Hot--tried several things __HELP

[LarsBars]

OK!

Still having problems witht he system getting very hot. Very close to danger zone. This is what I have don to date.

1. Replaced Thermostat, twice.
2. Checked water pump belt (have new one but not replaced) has plenty of tension.
3. Full flush with Prestone Super Flush, including installing the flush kit. So as to flush under pressure and not just draining radiator.
4. Replaced resvoir cap with new one. The old one said 15 PSI. Dealer said the computer calls for 18 PSI.

System builds pressure, (upper and lower hoses bet very stiff when operating temp is reached) so am I ok to assume the water pump is circulating coolant through the system? What about the fans, is there a switch or relay that says when they are supposed to run. They do not seem to run consisitenly when running above normal temps. Would this be enough to get the engine so hot? Please, any input would be greatly appreciated. Have been renting a car for past week to get this done and I am about at wits end.

[maxwedge]

Gets hot driving, at idle, do the hoses get hard very soon after starting? Are you loosing any coolant?

[LarsBars]

Originally Posted by maxwedge

Gets hot driving, at idle, do the hoses get hard very soon after starting? Are you loosing any coolant?

Gets hot driving quicker, but gets hot at idle too.

Hoses get hard at or near operating temp.

Not loosing any coolant, if I am it is not noticeable.

[Chris Stewart]

Do the hoses get tight while the motor is still cold?

[LarsBars]

Originally Posted by Chris Stewart

Do the hoses get tight while the motor is still cold?

Hoses get tight when at or near normal operating temperature. The fans come on high at or above 240 degrees(with A/C off). However they seem to be intermitment, they don't stay on until the engine is cooler. They seem to cycle on and off.

[GTP Dad]

It sounds like you may have air in the system. Getting hot quickly like that even at idle indicates there is a problem with the coolant circulating. Try opening the bleeder screw on the top of the thermostat housing and see if you get air or coolant. If you get air continue to bleed until all the air is out. Also make sure to turn the heater on high while doing this. Sometimes air gets trapped in the heater core and causes these issues.

[LarsBars]

Just ran a test.

Outside temp is 65.

Engine cold, not ran since yesterday.

Started car and let idle, and it took 17 minutes to reach 200. Then it took another 10 minutes to reach just below the next white line. Where it has been holding for 30minutes. Does this sound like a normal amount of time?

Water pump tensioner can be moved with little effort. Two fingers on a 6" socket handle. This seems too easy.

Do not see a bleeder screw near the thermostat. any one got a pic of this?

[fear reborn]

Our cars run hot, Running on the highway mine stays at about 200. Sitting in traffic it will reach 225-230 before fans kick on. We have a aluminum block with no grill and cramped engine bay. It's normal as long as it dose not get over 230.

[LarsBars]

Originally Posted by fear reborn

Our cars run hot, Running on the highway mine stays at about 200. Sitting in traffic it will reach 225-230 before fans kick on. We have a aluminum block with no grill and cramped engine bay. It's normal as long as it dose not get over 230.

Understood, That is what it used to do. But now it has been going over the 230 mark. and on several times just below the red danger marks.

I never did find a bleeder valve. But have tried to bleed through cap. Car seem to be holding at 200. But have not been up any big hills etc.

[kiway22]

Is your fan coming on around 220 degrees???

[tjm]

your thermostat isnt installed backwards is it? your anti-freeze is mixed 50% with water, right?

#1 - be sure all the air deflectors are in place under the car, then...

#2 - be sure you dont have a plastic bag or other debris up in front of the radiator, then...

#3 - replace sendy, then...

#4 - do a compression check to test for head gasket failure, then...

#5 - replace radiator

[LarsBars]

Originally Posted by kiway22

Is your fan coming on around 220 degrees???

disconnected the coolant level sensor and fan come on at 190 degrees.

[LarsBars]

Originally Posted by tjm

your thermostat isnt installed backwards is it? your anti-freeze is mixed 50% with water, right?

#1 - be sure all the air deflectors are in place under the car, then...

#2 - be sure you dont have a plastic bag or other debris up in front of the radiator, then...

#3 - replace sendy, then...

#4 - do a compression check to test for head gasket failure, then...

#5 - replace radiator

No the thermostat was replaced in the same manner as that was in there and yes coolant mixed to 50/50.

Bought new deflectors and have replaced. Airflow to radiator is clear of obstructions. What is sendy?

About a week ago I flushed the system again. And put new 50/50 mix in again. As car got near operating temperature release the coolant tank cap to let air out. Repeated this several times.

I have been driving the car on short neighorhood trips and the car has been holding right at 200 degrees.

Then today i take it for a longer trip, about 15 miles. Almost all down hill on the way there. Still holding right at 200. Then on the way home there is a steep hill, about 14 degree incline. Car goes right up the hill as it should. But as I crest the hill temp goes up quick. Warning hot turn A/C off comes on. A/C was not on. Pull the car over, turn heat on, and rev the car to about 2300 rpm. Temp goes down just as quick as it cam up. Only half way home. The temp did not drop back to 200 but closer to 225. And seemed to hold there, untill just about onto my street, and the temp starts to go up again. This is driving me nuts.

[ghutchin]

Maybe you have an intermittant problem with one of your fans or the fan relays.
Is it possible with our cars to see if the fans are running? I've never checked.

[LarsBars]

Yes you can not only see them but hear them. They come on low speed when you turn the A/C on. When the temp get hot they come on at high speed.